diff --git a/Bonus.h b/Bonus.h
index 27aafc0..bccc4e1 100755
--- a/Bonus.h
+++ b/Bonus.h
@@ -8,7 +8,7 @@
 #include "World.h"
 #include "Player.h"
 
-class Bonus : public Mesh {
+class Bonus : public RigidBody {
 protected:
     std::string _name;
 public:
diff --git a/Client.cpp b/Client.cpp
index e15e47e..fb50a9a 100755
--- a/Client.cpp
+++ b/Client.cpp
@@ -15,27 +15,27 @@ void Client::updatePacket() {
 void Client::spawnPlayer(sf::Uint16 id) {
     std::string name = "Player_" + std::to_string(id);
     _players.insert({ id, std::make_shared<Player>() });
-    (*_world).addMesh(_players[id], name);
+    (*_world).addBody(_players[id], name);
     _players[id]->setVisible(true);
     _players[id]->setAcceleration(Point4D{0, 0, 0});
 
     // add head and other stuff:
-    _world->loadObj(name + "_head", "../obj/cube.obj", "",Point4D{0.7, 0.7, 0.7});
-    (*_world)[name + "_head"]->translate(Point4D{0, 2, 0});
-    (*_world)[name + "_head"]->setCollider(false);
-    _players[id]->attach((*_world)[name + "_head"]);
+    _world->loadBody(name + "_head", "../obj/cube.obj", "", Point4D{0.7, 0.7, 0.7});
+    _world->body(name + "_head")->translate(Point4D{0, 2, 0});
+    _world->body(name + "_head")->setCollider(false);
+    _players[id]->attach(_world->body(name + "_head"));
 
-    _world->loadObj(name + "_eye1", "../obj/cube.obj", "",Point4D{0.2, 0.2, 0.05});
-    (*_world)[name + "_eye1"]->translate(Point4D{0.3, 2.1, 0.7});
-    (*_world)[name + "_eye1"]->setCollider(false);
-    (*_world)[name + "_eye1"]->setColor({147, 159, 255});
-    (*_world)[name + "_head"]->attach((*_world)[name + "_eye1"]);
+    _world->loadBody(name + "_eye1", "../obj/cube.obj", "", Point4D{0.2, 0.2, 0.05});
+    _world->body(name + "_eye1")->translate(Point4D{0.3, 2.1, 0.7});
+    _world->body(name + "_eye1")->setCollider(false);
+    _world->body(name + "_eye1")->setColor({147, 159, 255});
+    _world->body(name + "_head")->attach(_world->body(name + "_eye1"));
 
-    _world->loadObj(name + "_eye2", "../obj/cube.obj", "",Point4D{0.2, 0.2, 0.05});
-    (*_world)[name + "_eye2"]->translate(Point4D{-0.3, 2.1, 0.7});
-    (*_world)[name + "_eye2"]->setCollider(false);
-    (*_world)[name + "_eye2"]->setColor({147, 159, 255});
-    (*_world)[name + "_head"]->attach((*_world)[name + "_eye2"]);
+    _world->loadBody(name + "_eye2", "../obj/cube.obj", "", Point4D{0.2, 0.2, 0.05});
+    _world->body(name + "_eye2")->translate(Point4D{-0.3, 2.1, 0.7});
+    _world->body(name + "_eye2")->setCollider(false);
+    _world->body(name + "_eye2")->setColor({147, 159, 255});
+    _world->body(name + "_head")->attach(_world->body(name + "_eye2"));
 }
 
 void Client::processInit(sf::Packet& packet) {
@@ -64,7 +64,7 @@ void Client::processUpdate(sf::Packet& packet) {
             _players[targetId]->setHealth(buf[3]);
             _players[targetId]->rotateToAngle(Point4D{0, buf[4], 0});
 
-            (*_world)[name + "_head"]->rotate(Matrix4x4::RotationY(buf[4]) * Point4D{1, 0, 0},
+            _world->body(name + "_head")->rotate(Matrix4x4::RotationY(buf[4]) * Point4D{1, 0, 0},
                                               buf[5] - _players[targetId]->headAngle());
             _players[targetId]->setHeadAngle(buf[5]);
         } else if (targetId == _socket.ownId()) {
@@ -84,10 +84,10 @@ void Client::processNewClient(sf::Packet& packet) {
 void Client::processDisconnect(sf::Uint16 targetId) {
     if (targetId != _socket.ownId() && _players.count(targetId)) {
         std::string name = "Player_" + std::to_string(targetId);
-        _world->removeMesh(name);
-        _world->removeMesh(name + "_head");
-        _world->removeMesh(name + "_eye1");
-        _world->removeMesh(name + "_eye2");
+        _world->removeBody(name);
+        _world->removeBody(name + "_head");
+        _world->removeBody(name + "_eye1");
+        _world->removeBody(name + "_eye2");
 
         _players.erase(targetId);
     }
@@ -128,18 +128,19 @@ void Client::processCustomPacket(MsgType type, sf::Packet& packet) {
             p2 = Point4D(dbuff[3], dbuff[4], dbuff[5]);
 
             tmp = "Client_fireTraces_" + std::to_string(fireTraces++);
-            _world->addMesh(std::make_shared<Mesh>(Mesh::LineTo(p1, p2, 0.05)), tmp);
-            (*_world)[tmp]->setCollider(false);
+            _world->addBody(std::make_shared<RigidBody>(RigidBody(Mesh::LineTo(p1, p2, 0.05))), tmp);
+            _world->body(tmp)->setCollider(false);
 
-            (*_world)[tmp]->a_color(tmp + "_fadeOut", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
-            (*_world)["Player_im"]->a_function(tmp + "delete", [this, tmp](){ deleteTrace(_world, tmp); }, 1, 2);
+            _world->body(tmp)->a_color(tmp + "_fadeOut", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
+            _world->body("Player_im")->a_function(tmp + "delete", [this, tmp](){ deleteTrace(_world, tmp); }, 1, 2);
 
             break;
         case MsgType::InitBonuses:
             while (packet >> tmp >> dbuff[0] >> dbuff[1] >> dbuff[2]) {
                 tmp2 = tmp.substr(6, tmp.size()-3-5);
-                _world->addMesh(std::make_shared<Bonus>(tmp, "../obj/" + tmp2 + ".obj", "../obj/" + tmp2 + "_mat.txt", Point4D{3, 3, 3}), tmp);
-                (*_world)[tmp]->translateToPoint(Point4D(dbuff[0], dbuff[1], dbuff[2]));
+                _world->addBody(std::make_shared<Bonus>(tmp, "../obj/" + tmp2 + ".obj", "../obj/" + tmp2 + "_mat.txt",
+                                                        Point4D{3, 3, 3}), tmp);
+                _world->body(tmp)->translateToPoint(Point4D(dbuff[0], dbuff[1], dbuff[2]));
             }
             break;
 
@@ -147,13 +148,14 @@ void Client::processCustomPacket(MsgType type, sf::Packet& packet) {
             packet >> tmp >> dbuff[0] >> dbuff[1] >> dbuff[2];
 
             tmp2 = tmp.substr(6, tmp.size()-3-5);
-            _world->addMesh(std::make_shared<Bonus>(tmp, "../obj/" + tmp2 + ".obj", "../obj/" + tmp2 + "_mat.txt", Point4D{3, 3, 3}), tmp);
-            (*_world)[tmp]->translateToPoint(Point4D(dbuff[0], dbuff[1], dbuff[2]));
+            _world->addBody(std::make_shared<Bonus>(tmp, "../obj/" + tmp2 + ".obj", "../obj/" + tmp2 + "_mat.txt",
+                                                    Point4D{3, 3, 3}), tmp);
+            _world->body(tmp)->translateToPoint(Point4D(dbuff[0], dbuff[1], dbuff[2]));
 
             break;
         case MsgType::RemoveBonus:
             packet >> tmp;
-            _world->removeMesh(tmp);
+            _world->removeBody(tmp);
             break;
     }
 }
@@ -162,10 +164,10 @@ void Client::processDisconnected() {
     for (auto it = _players.begin(); it != _players.end();) {
         std::string name = "Player_" + std::to_string(it->first);
 
-        _world->removeMesh(name);
-        _world->removeMesh(name + "_head");
-        _world->removeMesh(name + "_eye1");
-        _world->removeMesh(name + "_eye2");
+        _world->removeBody(name);
+        _world->removeBody(name + "_head");
+        _world->removeBody(name + "_eye1");
+        _world->removeBody(name + "_eye2");
         _players.erase(it++);
     }
 }
@@ -187,7 +189,7 @@ void Client::addTrace(const Point4D& from, const Point4D& to) {
 }
 
 void Client::deleteTrace(std::shared_ptr<World> world, const std::string &traceName) {
-    world->removeMesh(traceName);
+    world->removeBody(traceName);
 }
 
 void Client::takeBonus(const std::string& bonusName) {
diff --git a/Client.h b/Client.h
index 9350cb6..ee517c8 100755
--- a/Client.h
+++ b/Client.h
@@ -21,7 +21,7 @@ private:
 
     void spawnPlayer(sf::Uint16 id);
 public:
-    Client(std::shared_ptr<Player>  player, std::shared_ptr<World>  world) : _player(std::move(player)), _world(std::move(world)) {};
+    Client(std::shared_ptr<Player>  player, std::shared_ptr<World>  world) : _player(player), _world(world) {};
 
     void updatePacket() override;
 
diff --git a/Player.cpp b/Player.cpp
index 2254028..8427d90 100755
--- a/Player.cpp
+++ b/Player.cpp
@@ -11,28 +11,28 @@ void Player::update() {
 
     // friction
     if(inCollision())
-        p_velocity = p_velocity - p_velocity*Time::deltaTime()*2;
+        _velocity = _velocity - _velocity * Time::deltaTime() * 2;
 
-    if(isInSlowMo) {
+    if(_isInSlowMo) {
         if(_ability > 0)
             _ability -= Time::deltaTime();
         else {
             _ability = 0;
-            isInSlowMo = false;
-            setVelocity(velocity()*slowMoCoefficient);
-            setAcceleration(p_acceleration*slowMoCoefficient*slowMoCoefficient);
-            slowMoSound.stop();
-            unSlowMoSound.play();
+            _isInSlowMo = false;
+            setVelocity(velocity() * _slowMoCoefficient);
+            setAcceleration(_acceleration * _slowMoCoefficient * _slowMoCoefficient);
+            _slowMoSound.stop();
+            _unSlowMoSound.play();
         }
     }
 
-    double coeff = isInSlowMo ? 1.0/slowMoCoefficient : 1.0;
+    double coeff = _isInSlowMo ? 1.0 / _slowMoCoefficient : 1.0;
 
-    bool inRunning_old = inRunning;
-    inRunning = _screen != nullptr && (Screen::isKeyPressed(sf::Keyboard::A) || Screen::isKeyPressed(sf::Keyboard::D) ||Screen::isKeyPressed(sf::Keyboard::W) || Screen::isKeyPressed(sf::Keyboard::S));
+    bool inRunning_old = _inRunning;
+    _inRunning = _screen != nullptr && (Screen::isKeyPressed(sf::Keyboard::A) || Screen::isKeyPressed(sf::Keyboard::D) || Screen::isKeyPressed(sf::Keyboard::W) || Screen::isKeyPressed(sf::Keyboard::S));
 
     // in case when the camera is attached we make some animation during running
-    if(_camera != nullptr && inRunning && !_camera->isInAnim()) {
+    if(_camera != nullptr && _inRunning && !_camera->isInAnim()) {
         _camera->a_translate("hor_oscil", -_camera->left()/12, 0.3/coeff, Animation::LoopOut::None, Animation::cos);
         _camera->a_wait("hor_oscil", 0);
         _camera->a_translate("hor_oscil", _camera->left()/12, 0.3/coeff, Animation::LoopOut::None, Animation::cos);
@@ -47,7 +47,7 @@ void Player::update() {
 
         _camera->a_translateToPoint("init", position() + Point4D{0, 1.8, 0}, 0.3/coeff, Animation::None, Animation::cos);
 
-    } else if(_camera != nullptr && inRunning_old && !inRunning) {
+    } else if(_camera != nullptr && inRunning_old && !_inRunning) {
         _camera->a_stopAllAnimations();
 
         _camera->a_translateToPoint("init", position() + Point4D{0, 1.8, 0}, 0.15/coeff, Animation::None, Animation::cos);
@@ -58,55 +58,55 @@ void Player::update() {
     if(_world != nullptr && _screen != nullptr && _camera != nullptr) {
         // Left and right
         if (Screen::isKeyPressed(sf::Keyboard::A)) {
-            translate(_camera->left() * Time::deltaTime() * walkSpeed * coeff);
+            translate(_camera->left() * Time::deltaTime() * _walkSpeed * coeff);
             if(inCollision())
                 setVelocity(Point4D{0,0,0});
         }
         if (Screen::isKeyPressed(sf::Keyboard::D)) {
-            translate(-_camera->left() * Time::deltaTime() * walkSpeed * coeff);
+            translate(-_camera->left() * Time::deltaTime() * _walkSpeed * coeff);
             if(inCollision())
                 setVelocity(Point4D{0,0,0});
         }
 
         // Forward and backward
         if (Screen::isKeyPressed(sf::Keyboard::W)) {
-            translate(_camera->left().cross3D(Point4D{0, 1, 0}) * Time::deltaTime() * walkSpeed * coeff);
+            translate(_camera->left().cross3D(Point4D{0, 1, 0}) * Time::deltaTime() * _walkSpeed * coeff);
             if(inCollision())
                 setVelocity(Point4D{0,0,0});
         }
 
         if (Screen::isKeyPressed(sf::Keyboard::S)) {
-            translate(-_camera->left().cross3D(Point4D{0, 1, 0}) * Time::deltaTime() * walkSpeed * coeff);
+            translate(-_camera->left().cross3D(Point4D{0, 1, 0}) * Time::deltaTime() * _walkSpeed * coeff);
 
             if(inCollision())
                 setVelocity(Point4D{0,0,0});
         }
 
-        if (_ability > 0 && !isInSlowMo && Screen::isKeyPressed(sf::Keyboard::LShift)) {
+        if (_ability > 0 && !_isInSlowMo && Screen::isKeyPressed(sf::Keyboard::LShift)) {
             // slow mo
-            isInSlowMo = true;
-            setVelocity(velocity()/slowMoCoefficient);
-            setAcceleration(p_acceleration/(slowMoCoefficient*slowMoCoefficient));
-            unSlowMoSound.stop();
-            slowMoSound.play();
-        } else if (isInSlowMo && !Screen::isKeyPressed(sf::Keyboard::LShift)) {
-            isInSlowMo = false;
-            setVelocity(velocity()*slowMoCoefficient);
-            setAcceleration(p_acceleration*slowMoCoefficient*slowMoCoefficient);
-            slowMoSound.stop();
-            unSlowMoSound.play();
+            _isInSlowMo = true;
+            setVelocity(velocity() / _slowMoCoefficient);
+            setAcceleration(_acceleration / (_slowMoCoefficient * _slowMoCoefficient));
+            _unSlowMoSound.stop();
+            _slowMoSound.play();
+        } else if (_isInSlowMo && !Screen::isKeyPressed(sf::Keyboard::LShift)) {
+            _isInSlowMo = false;
+            setVelocity(velocity() * _slowMoCoefficient);
+            setAcceleration(_acceleration * _slowMoCoefficient * _slowMoCoefficient);
+            _slowMoSound.stop();
+            _unSlowMoSound.play();
         }
 
         if (Screen::isKeyPressed(sf::Keyboard::Space) && inCollision()) {
-            addVelocity(Point4D{0, std::abs(_collisionNormal.y())*sqrt(2 * g * jumpHeight)*coeff, 0});
-            translate(Point4D{0, Time::deltaTime() * walkSpeed * 2 * coeff, 0});
+            addVelocity(Point4D{0, std::abs(_collisionNormal.y()) * sqrt(2 * _g * _jumpHeight) * coeff, 0});
+            translate(Point4D{0, Time::deltaTime() * _walkSpeed * 2 * coeff, 0});
         }
 
         // Mouse movement
         Point4D disp = _screen->getMouseDisplacement();
 
         rotate(Point4D{0, -disp.x() / 1000.0, 0});
-        p_velocity = Matrix4x4::RotationY(-disp.x() / 1000.0)*p_velocity;
+        _velocity = Matrix4x4::RotationY(-disp.x() / 1000.0) * _velocity;
 
         double rotationLeft = disp.y() / 1000.0;
 
@@ -126,7 +126,7 @@ void Player::update() {
                 _selectedWeapon = (_selectedWeapon + 1) % _weapons.size();
                 _weapons[_selectedWeapon]->addToWorld(_world);
                 Log::log("selected _selectedWeapon " + std::to_string(_selectedWeapon));
-                changeWeaponSound.play();
+                _changeWeaponSound.play();
             }
         }
 
@@ -140,7 +140,7 @@ void Player::update() {
                     _selectedWeapon = _weapons.size() - 1;
                 _weapons[_selectedWeapon]->addToWorld(_world);
                 Log::log("selected _selectedWeapon " + std::to_string(_selectedWeapon));
-                changeWeaponSound.play();
+                _changeWeaponSound.play();
             }
         }
 
@@ -148,7 +148,7 @@ void Player::update() {
             auto damagedPlayers = _weapons[_selectedWeapon]->fire(_world, _camera);
             for(auto& damagedPlayer : damagedPlayers) {
                 sf::Uint16 targetId = std::stoi(damagedPlayer.first.substr(7));
-                damagePlayerCallBack(targetId, damagedPlayer.second);
+                _damagePlayerCallBack(targetId, damagedPlayer.second);
             }
         }
 
@@ -156,11 +156,11 @@ void Player::update() {
             _weapons[_selectedWeapon]->reload();
         }
 
-        if (inRunning && inCollision() && walkSound.getStatus() != sf::Sound::Status::Playing) {
+        if (_inRunning && inCollision() && _walkSound.getStatus() != sf::Sound::Status::Playing) {
             if ((position() - rayToFloor.first).abs() < 2) {
                 int soundNum = round((double) rand() / RAND_MAX * 5) + 1;
-                walkSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/stonestep" + std::to_string(soundNum) + ".ogg"));
-                walkSound.play();
+                _walkSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/stonestep" + std::to_string(soundNum) + ".ogg"));
+                _walkSound.play();
             }
         }
     }
@@ -248,7 +248,7 @@ void Player::drawStats() {
     text_ammo2.setFillColor(sf::Color(0, 0, 0, 70));
     _screen->window.draw(text_ammo2);
 
-    // text killSound/deathSound stats
+    // text _killSound/_deathSound stats
     sf::Text text_kills(text_health);
     text_kills.setStyle(sf::Text::Bold);
     text_kills.setString("KILLS: " + std::to_string((int)_kills) + " | " + "DEATHS: " + std::to_string((int)_deaths));
@@ -267,16 +267,16 @@ void Player::drawStats() {
 }
 
 void Player::playDeath() {
-    deathSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/classic_hurt.ogg"));
-    deathSound.play();
+    _deathSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/classic_hurt.ogg"));
+    _deathSound.play();
 }
 
 void Player::playKill() {
-    killSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/kill.ogg"));
-    killSound.play();
+    _killSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/kill.ogg"));
+    _killSound.play();
 }
 
-void Player::collisionWithObject(const std::string &objName, std::shared_ptr<Mesh> obj) {
+void Player::collisionWithObject(const std::string &objName, std::shared_ptr<RigidBody> obj) {
     if(objName.find("Bonus_gun") != std::string::npos)
         addWeapon(std::make_shared<Gun>());
 
@@ -299,13 +299,13 @@ void Player::collisionWithObject(const std::string &objName, std::shared_ptr<Mes
         setFullAbility();
 
     if(objName.find("Bonus") != std::string::npos) {
-        _world->removeMesh(objName);
-        takeBonusCallBack(objName);
+        _world->removeBody(objName);
+        _takeBonusCallBack(objName);
     }
 }
 
 void Player::addWeapon(std::shared_ptr<Weapon> weapon) {
-    changeWeaponSound.play();
+    _changeWeaponSound.play();
 
     if(!_weapons.empty()) {
         for(auto& w : _weapons) {
@@ -320,11 +320,11 @@ void Player::addWeapon(std::shared_ptr<Weapon> weapon) {
     _weapons.back()->attachToPlayer(*this);
 
     _weapons.back()->translate(position());
-    _weapons.back()->rotateRelativePoint(position() + Point4D{0, 1.8, 0}, Point4D{0, 1, 0}, p_angle.y());
+    _weapons.back()->rotateRelativePoint(position() + Point4D{0, 1.8, 0}, Point4D{0, 1, 0}, _angle.y());
     _weapons.back()->rotateRelativePoint(position() + Point4D{0, 1.8, 0}, _camera->left(), _camera->angleLeftUpLookAt().x());
 
-    _weapons.back()->setAddTraceCallBack(addTraceCallBack);
-    changeWeaponSound.play();
+    _weapons.back()->setAddTraceCallBack(_addTraceCallBack);
+    _changeWeaponSound.play();
 }
 
 void Player::initWeapons() {
diff --git a/Player.h b/Player.h
index 03c2c88..d2e7bab 100755
--- a/Player.h
+++ b/Player.h
@@ -8,7 +8,6 @@
 #include <SFML/Audio/Sound.hpp>
 #include <utility>
 #include <ResourceManager.h>
-#include "Mesh.h"
 #include "Camera.h"
 #include "World.h"
 #include "weapon/Ak47.h"
@@ -17,7 +16,7 @@
 #include "weapon/Gold_Ak47.h"
 #include "weapon/Rifle.h"
 
-class Player : public Mesh{
+class Player : public RigidBody{
 private:
     double _healthMax = 100;
     double _health = _healthMax;
@@ -25,80 +24,80 @@ private:
     double _abilityMax = 10;
     double _ability = _abilityMax;
 
-    double jumpHeight = 3;
-    double walkSpeed = 10;
+    double _jumpHeight = 3;
+    double _walkSpeed = 10;
     double _headAngle = 0;
 
     unsigned _kills = 0;
     unsigned _deaths = 0;
 
-    double g = 35;
+    double _g = 35;
 
-    double slowMoCoefficient = 5;
-    bool isInSlowMo = false;
+    double _slowMoCoefficient = 5;
+    bool _isInSlowMo = false;
 
     std::shared_ptr<Camera> _camera;
     std::shared_ptr<Screen> _screen;
 
     std::shared_ptr<World> _world;
 
-    bool inRunning = false;
+    bool _inRunning = false;
 
     // sounds
-    sf::Sound killSound;
-    sf::Sound deathSound;
-    sf::Sound walkSound;
-    sf::Sound changeWeaponSound;
-    sf::Sound slowMoSound;
-    sf::Sound unSlowMoSound;
-    sf::Sound fullHealthSound;
-    sf::Sound fullAbilitySound;
+    sf::Sound _killSound;
+    sf::Sound _deathSound;
+    sf::Sound _walkSound;
+    sf::Sound _changeWeaponSound;
+    sf::Sound _slowMoSound;
+    sf::Sound _unSlowMoSound;
+    sf::Sound _fullHealthSound;
+    sf::Sound _fullAbilitySound;
 
     std::string _name = "im";
 
     std::vector<std::shared_ptr<Weapon>> _weapons;
     uint8_t _selectedWeapon = 0;
 
-    std::function<void(sf::Uint16 targetId, double)> damagePlayerCallBack;
-    std::function<void(const Point4D&, const Point4D&)> addTraceCallBack;
-    std::function<void(const std::string&)> takeBonusCallBack;
+    std::function<void(sf::Uint16 targetId, double)> _damagePlayerCallBack;
+    std::function<void(const Point4D&, const Point4D&)> _addTraceCallBack;
+    std::function<void(const std::string&)> _takeBonusCallBack;
 
 
 public:
     Player() {
         loadObj("../obj/cube.obj", "", Point4D{0.5, 1.9, 0.5});
-        setAcceleration(Point4D{0, -g, 0});
+        setAcceleration(Point4D{0, -_g, 0});
         setCollision(true);
         setVisible(false);
         setColor({240, 168, 168});
+
+        _changeWeaponSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/weapons/change_weapon.ogg"));
+
+        _slowMoSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/slow_mo.ogg"));
+        _unSlowMoSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/unslow_mo.ogg"));
+
+        _fullHealthSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/fullHealth.ogg"));
+        _fullAbilitySound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/fullAbility.ogg"));
+
+        setCollisionCallBack([this](const std::string& objName, std::shared_ptr<RigidBody> obj) {collisionWithObject(objName, obj);});
     };
 
     void update();
 
     void attachCamera(std::shared_ptr<Camera> camera, std::shared_ptr<Screen> screen) {
-        _camera = std::move(camera);
-        _screen = std::move(screen);
+        _camera = camera;
+        _screen = screen;
 
         _camera->translateToPoint(position() + Point4D{0, 1.8, 0});
         this->attach(_camera);
     }
 
     void attachWorld(std::shared_ptr<World> world, const Point4D& pos = Point4D{0, 30, 0}) {
-        _world = std::move(world);
+        _world = world;
 
         translate(pos);
 
         initWeapons();
-
-        changeWeaponSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/weapons/change_weapon.ogg"));
-
-        slowMoSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/slow_mo.ogg"));
-        unSlowMoSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/unslow_mo.ogg"));
-
-        fullHealthSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/fullHealth.ogg"));
-        fullAbilitySound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/fullAbility.ogg"));
-
-        setCollisionCallBack([this](const std::string& objName, std::shared_ptr<Mesh> obj) {collisionWithObject(objName, std::move(obj));});
     }
 
     void setHealth(double h) {
@@ -110,24 +109,24 @@ public:
 
     void setFullHealth() {
         _health = _healthMax;
-        fullHealthSound.play();
+        _fullHealthSound.play();
     }
     void setFullAbility() {
         _ability = _abilityMax;
-        fullAbilitySound.play();
+        _fullAbilitySound.play();
     }
 
 
     void setDamagePlayerCallBack(std::function<void(sf::Uint16 targetId, double)> hit) {
-        damagePlayerCallBack = std::move(hit);
+        _damagePlayerCallBack = std::move(hit);
     }
 
     void setAddTraceCallBack(std::function<void(const Point4D&, const Point4D&)> add) {
-        addTraceCallBack = std::move(add);
+        _addTraceCallBack = std::move(add);
     }
 
     void setTakeBonusCallBack(std::function<void(const std::string&)> take) {
-        takeBonusCallBack = std::move(take);
+        _takeBonusCallBack = std::move(take);
     }
 
     [[nodiscard]] double health() const { return _health; }
@@ -151,7 +150,7 @@ public:
     void playDeath();
     void playKill();
 
-    void collisionWithObject(const std::string& objName, std::shared_ptr<Mesh> obj);
+    void collisionWithObject(const std::string& objName, std::shared_ptr<RigidBody> obj);
 
     void addWeapon(std::shared_ptr<Weapon> weapon);
 
diff --git a/engine/Camera.cpp b/engine/Camera.cpp
index 5aa0978..ff65b70 100755
--- a/engine/Camera.cpp
+++ b/engine/Camera.cpp
@@ -5,25 +5,25 @@
 #include "Camera.h"
 #include "utils/Log.h"
 
-std::vector<Triangle> &Camera::project(Mesh& mesh, Screen::ViewMode mode) {
+std::vector<Triangle> &Camera::project(std::shared_ptr<Mesh> mesh) {
 
-    if(!ready) {
-        Log::log("Camera::project(): cannot project tris without camera initialization ( Camera::init() ) ");
-        return this->triangles;
+    if(!_ready) {
+        Log::log("Camera::project(): cannot project _tris without camera initialization ( Camera::init() ) ");
+        return this->_triangles;
     }
 
-    if(!mesh.isVisible())
-        return this->triangles;
+    if(!mesh->isVisible())
+        return this->_triangles;
 
-    // Model transform matrix: translate tris in the origin of mesh.
-    Matrix4x4 M = Matrix4x4::Translation(mesh.position());
-    VM = V * M;
+    // Model transform matrix: translate _tris in the origin of body.
+    Matrix4x4 M = Matrix4x4::Translation(mesh->position());
+    Matrix4x4 VM = _V * M;
 
     // We don't want to waste time re-allocating memory every time
     std::vector<Triangle> clippedTriangles, tempBuffer;
-    for(auto& t : mesh.triangles()) {
+    for(auto& t : mesh->triangles()) {
 
-        double dot = t.norm().dot((mesh.position() + t[0] - p_position).normalized());
+        double dot = t.norm().dot((mesh->position() + t[0] - _position).normalized());
 
         if(dot > 0)
             continue;
@@ -32,10 +32,10 @@ std::vector<Triangle> &Camera::project(Mesh& mesh, Screen::ViewMode mode) {
         // It needs to be cleared because it's reused through iterations. Usually it doesn't free memory.
         clippedTriangles.clear();
 
-        // In the beginning we need to to translate triangle from world coordinate to our camera system:
-        // After that we apply clipping for all planes from clipPlanes
+        // In the beginning we need to to translate drawTriangle from world coordinate to our camera system:
+        // After that we apply clipping for all planes from _clipPlanes
         clippedTriangles.emplace_back(t * VM);
-        for(auto& plane : clipPlanes)
+        for(auto& plane : _clipPlanes)
         {
             while(!clippedTriangles.empty())
             {
@@ -51,60 +51,59 @@ std::vector<Triangle> &Camera::project(Mesh& mesh, Screen::ViewMode mode) {
         }
 
         for(auto& clippedTriangle : clippedTriangles) {
-            if(mode != Screen::ViewMode::Clipped) {
-                clippedTriangle.color = sf::Color(clippedTriangle.color.r * (0.3 * std::abs(dot) + 0.7),
-                                                  clippedTriangle.color.g * (0.3 * std::abs(dot) + 0.7),
-                                                  clippedTriangle.color.b * (0.3 * std::abs(dot) + 0.7),
-                                                  (mode == Screen::ViewMode::Transparency ||
-                                                   mode == Screen::ViewMode::Normals) ? 100 : clippedTriangle.color.a);
-            }
+            sf::Color color = clippedTriangle.color();
+            sf::Color ambientColor = sf::Color(color.r * (0.3 * std::abs(dot) + 0.7),
+                                               color.g * (0.3 * std::abs(dot) + 0.7),
+                                               color.b * (0.3 * std::abs(dot) + 0.7),
+                                               color.a);
 
-            // Finally its time to project our clipped colored triangle from 3D -> 2D
+            // Finally its time to project our clipped colored drawTriangle from 3D -> 2D
             // and transform it's coordinate to screen space (in pixels):
-            clippedTriangle *= SP;
+            clippedTriangle = clippedTriangle * _SP;
 
-            clippedTriangle[0] = clippedTriangle[0] / clippedTriangle[0].w();
-            clippedTriangle[1] = clippedTriangle[1] / clippedTriangle[1].w();
-            clippedTriangle[2] = clippedTriangle[2] / clippedTriangle[2].w();
+            clippedTriangle = Triangle(clippedTriangle[0] / clippedTriangle[0].w(),
+                                       clippedTriangle[1] / clippedTriangle[1].w(),
+                                       clippedTriangle[2] / clippedTriangle[2].w(),
+                                       ambientColor);
 
-            triangles.emplace_back(clippedTriangle);
+            _triangles.emplace_back(clippedTriangle);
         }
     }
 
-    return this->triangles;
+    return this->_triangles;
 }
 
 void Camera::init(int width, int height, double fov, double ZNear, double ZFar) {
     // We need to init camera only after creation or changing width, height, fov, ZNear or ZFar.
     // Because here we calculate matrix that does not change during the motion of _objects or camera
-    w = width; h = height;
-    aspect = (double)width / (double)height;
-    P = Matrix4x4::Projection(fov, aspect, ZNear, ZFar);
-    S = Matrix4x4::ScreenSpace(width, height);
+    _w = width; _h = height;
+    _aspect = (double)width / (double)height;
+    _P = Matrix4x4::Projection(fov, _aspect, ZNear, ZFar);
+    _S = Matrix4x4::ScreenSpace(width, height);
 
-    SP = S * P; // screen-space-projections matrix
+    _SP = _S * _P; // screen-space-projections matrix
 
-    // This is planes for clipping tris.
-    // Motivation: we are not interest in tris that we cannot see.
-    clipPlanes.emplace_back(Plane(Point4D{0, 0, 1}, Point4D{0, 0, ZNear})); // near plane
-    clipPlanes.emplace_back(Plane(Point4D{0, 0, -1}, Point4D{0, 0, ZFar})); // far plane
+    // This is planes for clipping _tris.
+    // Motivation: we are not interest in _tris that we cannot see.
+    _clipPlanes.emplace_back(Plane(Point4D{0, 0, 1}, Point4D{0, 0, ZNear})); // near plane
+    _clipPlanes.emplace_back(Plane(Point4D{0, 0, -1}, Point4D{0, 0, ZFar})); // far plane
 
     double thetta1 = M_PI*fov*0.5/180.0;
-    double thetta2 = atan(aspect*tan(thetta1));
-    clipPlanes.emplace_back(Plane(Point4D{-cos(thetta2), 0, sin(thetta2)}, Point4D{0, 0, 0})); // left plane
-    clipPlanes.emplace_back(Plane(Point4D{cos(thetta2), 0, sin(thetta2)}, Point4D{0, 0, 0})); // right plane
-    clipPlanes.emplace_back(Plane(Point4D{0, cos(thetta1), sin(thetta1)}, Point4D{0, 0, 0})); // down plane
-    clipPlanes.emplace_back(Plane(Point4D{0, -cos(thetta1), sin(thetta1)},Point4D{0, 0, 0})); // up plane
+    double thetta2 = atan(_aspect * tan(thetta1));
+    _clipPlanes.emplace_back(Plane(Point4D{-cos(thetta2), 0, sin(thetta2)}, Point4D{0, 0, 0})); // left plane
+    _clipPlanes.emplace_back(Plane(Point4D{cos(thetta2), 0, sin(thetta2)}, Point4D{0, 0, 0})); // right plane
+    _clipPlanes.emplace_back(Plane(Point4D{0, cos(thetta1), sin(thetta1)}, Point4D{0, 0, 0})); // down plane
+    _clipPlanes.emplace_back(Plane(Point4D{0, -cos(thetta1), sin(thetta1)}, Point4D{0, 0, 0})); // up plane
 
-    ready = true;
+    _ready = true;
     Log::log("Camera::init(): camera successfully initialized.");
 }
 
 std::vector<Triangle> &Camera::sorted() {
 
-    // Sort tris from back to front
+    // Sort _tris from back to front
     // This is some replacement for Z-buffer
-    std::sort(triangles.begin(), triangles.end(), [](Triangle &t1, Triangle &t2)
+    std::sort(_triangles.begin(), _triangles.end(), [](Triangle &t1, Triangle &t2)
     {
         std::vector<double> v_z1({t1[0].z(), t1[1].z(), t1[2].z()});
         std::vector<double> v_z2({t2[0].z(), t2[1].z(), t2[2].z()});
@@ -118,44 +117,44 @@ std::vector<Triangle> &Camera::sorted() {
         return z1 > z2;
     });
 
-    return triangles;
+    return _triangles;
 }
 
-void Camera::record() {
-    // Cleaning all tris and recalculation of View matrix
+void Camera::clear() {
+    // Cleaning all _tris and recalculation of View matrix
     // That is like preparation for new camera shot: we need to set
     // the position of camera and insert new cartridge for photo.
-    triangles.clear();
-    V = Matrix4x4::View(p_left, p_up, p_lookAt, p_position);
+    _triangles.clear();
+    _V = Matrix4x4::View(_left, _up, _lookAt, _position);
 }
 
 void Camera::rotateX(double rx) {
-    p_angle = Point4D{p_angle.x() + rx, p_angle.y(), p_angle.z()};
-    p_left = Matrix4x4::RotationX(rx) * p_left;
-    p_up = Matrix4x4::RotationX(rx) * p_up;
-    p_lookAt = Matrix4x4::RotationX(rx) * p_lookAt;
+    _angle = Point4D{_angle.x() + rx, _angle.y(), _angle.z()};
+    _left = Matrix4x4::RotationX(rx) * _left;
+    _up = Matrix4x4::RotationX(rx) * _up;
+    _lookAt = Matrix4x4::RotationX(rx) * _lookAt;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), Point4D{rx, 0, 0});
 }
 
 void Camera::rotateY(double ry) {
-    p_angle = Point4D{p_angle.x(), p_angle.y() + ry, p_angle.z()};
-    p_left = Matrix4x4::RotationY(ry) * p_left;
-    p_up = Matrix4x4::RotationY(ry) * p_up;
-    p_lookAt = Matrix4x4::RotationY(ry) * p_lookAt;
+    _angle = Point4D{_angle.x(), _angle.y() + ry, _angle.z()};
+    _left = Matrix4x4::RotationY(ry) * _left;
+    _up = Matrix4x4::RotationY(ry) * _up;
+    _lookAt = Matrix4x4::RotationY(ry) * _lookAt;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), Point4D{0, ry, 0});
 }
 
 void Camera::rotateZ(double rz) {
-    p_angle = Point4D{p_angle.x(), p_angle.y(), p_angle.z() + rz};
-    p_left = Matrix4x4::RotationZ(rz) * p_left;
-    p_up = Matrix4x4::RotationZ(rz) * p_up;
-    p_lookAt = Matrix4x4::RotationZ(rz) * p_lookAt;
+    _angle = Point4D{_angle.x(), _angle.y(), _angle.z() + rz};
+    _left = Matrix4x4::RotationZ(rz) * _left;
+    _up = Matrix4x4::RotationZ(rz) * _up;
+    _lookAt = Matrix4x4::RotationZ(rz) * _lookAt;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), Point4D{0, 0, rz});
 }
 
@@ -167,69 +166,69 @@ void Camera::rotate(const Point4D& r) {
 
 
 void Camera::rotate(const Point4D& v, double rv) {
-    p_left = Matrix4x4::Rotation(v, rv) * p_left;
-    p_up = Matrix4x4::Rotation(v, rv) * p_up;
-    p_lookAt = Matrix4x4::Rotation(v, rv) * p_lookAt;
+    _left = Matrix4x4::Rotation(v, rv) * _left;
+    _up = Matrix4x4::Rotation(v, rv) * _up;
+    _lookAt = Matrix4x4::Rotation(v, rv) * _lookAt;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), v, rv);
 }
 
 void Camera::rotateLeft(double rl) {
-    p_angleLeftUpLookAt = Point4D{p_angleLeftUpLookAt.x() + rl, p_angleLeftUpLookAt.y(), p_angleLeftUpLookAt.z()};
+    _angleLeftUpLookAt = Point4D{_angleLeftUpLookAt.x() + rl, _angleLeftUpLookAt.y(), _angleLeftUpLookAt.z()};
 
-    rotate(p_left, rl);
+    rotate(_left, rl);
 
-    for(auto attached : v_attached)
-        attached->rotateRelativePoint(position(), p_left, rl);
+    for(auto attached : _attachedObjects)
+        attached->rotateRelativePoint(position(), _left, rl);
 }
 
 void Camera::rotateUp(double ru) {
-    p_angleLeftUpLookAt = Point4D{p_angleLeftUpLookAt.x(), p_angleLeftUpLookAt.y() + ru, p_angleLeftUpLookAt.z()};
-    rotate(p_up, ru);
+    _angleLeftUpLookAt = Point4D{_angleLeftUpLookAt.x(), _angleLeftUpLookAt.y() + ru, _angleLeftUpLookAt.z()};
+    rotate(_up, ru);
 
-    for(auto attached : v_attached)
-        attached->rotateRelativePoint(position(), p_up, ru);
+    for(auto attached : _attachedObjects)
+        attached->rotateRelativePoint(position(), _up, ru);
 }
 
 void Camera::rotateLookAt(double rlAt) {
-    p_angleLeftUpLookAt = Point4D{p_angleLeftUpLookAt.x(), p_angleLeftUpLookAt.y(), p_angleLeftUpLookAt.z() + rlAt};
-    rotate(p_lookAt, rlAt);
+    _angleLeftUpLookAt = Point4D{_angleLeftUpLookAt.x(), _angleLeftUpLookAt.y(), _angleLeftUpLookAt.z() + rlAt};
+    rotate(_lookAt, rlAt);
 
-    for(auto attached : v_attached)
-        attached->rotateRelativePoint(position(), p_lookAt, rlAt);
+    for(auto attached : _attachedObjects)
+        attached->rotateRelativePoint(position(), _lookAt, rlAt);
 }
 
 void Camera::rotateRelativePoint(const Point4D &s, const Point4D &r) {
-    p_angle = p_angle + r;
+    _angle = _angle + r;
 
     // Translate XYZ by vector r1
-    Point4D r1 = p_position - s;
+    Point4D r1 = _position - s;
     // In translated coordinate system we rotate camera and position
     Point4D r2 = Matrix4x4::Rotation(r)*r1;
     rotate(r);
 
     // After rotation we translate XYZ by vector -r2 and recalculate position
-    p_position = s + r2;
+    _position = s + r2;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(s, r);
 }
 
 void Camera::rotateRelativePoint(const Point4D &s, const Point4D &v, double r) {
     // Translate XYZ by vector r1
-    Point4D r1 = p_position - s;
+    Point4D r1 = _position - s;
     // In translated coordinate system we rotate camera and position
     Point4D r2 = Matrix4x4::Rotation(v, r)*r1;
     rotate(v, r);
 
     // After rotation we translate XYZ by vector -r2 and recalculate position
-    p_position = s + r2;
+    _position = s + r2;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(s, v, r);
 }
 
 void Camera::translateToPoint(const Point4D &point) {
-    translate(point - p_position);
+    translate(point - _position);
 }
diff --git a/engine/Camera.h b/engine/Camera.h
index 5162557..9f3ccee 100755
--- a/engine/Camera.h
+++ b/engine/Camera.h
@@ -12,29 +12,28 @@
 
 class Camera : public Object, public Animatable{
 private:
-    Point4D p_angleLeftUpLookAt;
+    Point4D _angleLeftUpLookAt;
 
-    Point4D p_left =    Point4D{1, 0, 0, 0}; // internal X
-    Point4D p_up =      Point4D{0, 1, 0, 0}; // internal Y
-    Point4D p_lookAt =  Point4D{0, 0, 1, 0}; // internal Z
+    Point4D _left =    Point4D{1, 0, 0, 0}; // internal X
+    Point4D _up =      Point4D{0, 1, 0, 0}; // internal Y
+    Point4D _lookAt =  Point4D{0, 0, 1, 0}; // internal Z
 
-    Matrix4x4 S; // screen space matrix
-    Matrix4x4 P; // projections matrix
-    Matrix4x4 V; // camera matrix
+    Matrix4x4 _S; // screen space matrix
+    Matrix4x4 _P; // projections matrix
+    Matrix4x4 _V; // camera matrix
 
-    double aspect = 0;
+    double _aspect = 0;
 
     // To accelerate calculations we can use precalculated matrix that does not chance
-    Matrix4x4 SP; // screen-space-projections matrix
-    Matrix4x4 VM; // camera-model-animation matrix
+    Matrix4x4 _SP; // screen-space-projections matrix
 
-    std::vector<Triangle> triangles;
-    std::vector<Plane> clipPlanes;
+    std::vector<Triangle> _triangles;
+    std::vector<Plane> _clipPlanes;
 
-    bool ready = false;
+    bool _ready = false;
 
-    double w = 0;
-    double h = 0;
+    double _w = 0;
+    double _h = 0;
 public:
     Camera() = default;
     Camera(const Camera& camera) = delete;
@@ -42,28 +41,28 @@ public:
 
     void init(int width, int height, double fov = 110.0, double ZNear = 0.1, double ZFar = 5000.0);
 
-    std::vector<Triangle>& project(Mesh& mesh, Screen::ViewMode mode);
+    std::vector<Triangle>& project(std::shared_ptr<Mesh> mesh);
 
-    void record();
+    void clear();
 
-    [[nodiscard]] int buffSize() const { return triangles.size(); }
+    [[nodiscard]] int buffSize() const { return _triangles.size(); }
     std::vector<Triangle>& sorted();
 
-    [[nodiscard]] Point4D position() const override { return p_position; }
-    [[nodiscard]] Point4D angle() const override { return p_angle; }
-    [[nodiscard]] Point4D angleLeftUpLookAt() const { return p_angleLeftUpLookAt; }
+    [[nodiscard]] Point4D position() const override { return _position; }
+    [[nodiscard]] Point4D angle() const override { return _angle; }
+    [[nodiscard]] Point4D angleLeftUpLookAt() const { return _angleLeftUpLookAt; }
 
-    [[nodiscard]] Point4D eye() const { return p_position; }
-    [[nodiscard]] Point4D left() const { return p_left; }
-    [[nodiscard]] Point4D right() const { return -p_left; }
-    [[nodiscard]] Point4D up() const { return p_up; }
-    [[nodiscard]] Point4D down() const { return -p_up; }
-    [[nodiscard]] Point4D lookAt() const { return p_lookAt; }
+    [[nodiscard]] Point4D eye() const { return _position; }
+    [[nodiscard]] Point4D left() const { return _left; }
+    [[nodiscard]] Point4D right() const { return -_left; }
+    [[nodiscard]] Point4D up() const { return _up; }
+    [[nodiscard]] Point4D down() const { return -_up; }
+    [[nodiscard]] Point4D lookAt() const { return _lookAt; }
 
     void translate(const Point4D& dv) override {
-        p_position = p_position + dv;
+        _position = _position + dv;
 
-        for(auto attached : v_attached)
+        for(auto attached : _attachedObjects)
             attached->translate(dv);
     }
 
@@ -80,9 +79,9 @@ public:
     void rotateUp(double ru);
     void rotateLookAt(double rlAt);
 
-    // Rotate mesh around XYZ by (r.x, r.y, r.z) radians relative val 'point4D'
+    // Rotate body around XYZ by (r.x, r.y, r.z) radians relative val 'point4D'
     void rotateRelativePoint(const Point4D& s, const Point4D& r) override;
-    // Rotate mesh around normalised vector 'v' by 'r' radians relative val 'point4D'
+    // Rotate body around normalised vector 'v' by 'r' radians relative val 'point4D'
     void rotateRelativePoint(const Point4D& s, const Point4D& v, double r) override;
 };
 
diff --git a/engine/Engine.cpp b/engine/Engine.cpp
index 196b772..6ab3048 100755
--- a/engine/Engine.cpp
+++ b/engine/Engine.cpp
@@ -15,6 +15,8 @@ Engine::Engine() {
 }
 
 void Engine::create(int screenWidth, int screenHeight, const std::string &name, bool verticalSync, sf::Color background, sf::Uint32 style) {
+    _name = name;
+
     screen->open(screenWidth, screenHeight, name, verticalSync, background, style);
 
     Log::log("Engine::create(): started engine (" + std::to_string(screenWidth) + " x " + std::to_string(screenHeight) + ") with name '" + name + "'.");
@@ -28,67 +30,35 @@ void Engine::create(int screenWidth, int screenHeight, const std::string &name,
         screen->clear();
 
         Time::update();
-        screen->keyboardControl();
-        update(Time::deltaTime());
+        update();
 
         world->garbageCollector();
         /* Project all mesh
-         * Here we project all tris for each mesh from world._objects.
+         * Here we project all _tris for each body from world._objects.
          * When we call camera.project(m.second),
          */
 
         // sometimes we dont need to update physics world
         // (for example in menu or while pause)
-        // hence we can set 'b_updateWorld' equal to false in setUpdateWorld(bool):
-        if(b_updateWorld) {
-            camera->record();
-            for (auto &m : world->objects()) {
-                m.second->a_update();
-                camera->project(*m.second, screen->mode());
-
-                m.second->updatePhysicsState();
-                // isCollision detection:
-                if (m.second->isCollision()) {
-                    m.second->setInCollision(false);
-                    m.second->setCollisionNormal(Point4D{0, 0, 0});
-                    for (auto &obj : world->objects()) {
-                        if(obj.first != m.first) {
-                            std::pair<bool, Simplex> gjk = m.second->checkGJKCollision(obj.second);
-                            if (gjk.first) {
-                                if (obj.second->isCollider()) {
-                                    CollisionPoint epa = m.second->EPA(gjk.second, obj.second);
-                                    Solver::solveCollision(m.second, obj.second, epa);
-                                }
-                                if (m.second->collisionCallBack() != nullptr)
-                                    m.second->collisionCallBack()(obj.first, obj.second);
-                            }
-                        }
-                    }
-                }
-
-            }
-
-            // draw projected mesh
-            for (auto &t : camera->sorted())
-                screen->triangle(t);
+        // hence we can set '_updateWorld' equal to false in setUpdateWorld(bool):
+        if(_updateWorld) {
 
             camera->a_update();
+            camera->clear();
 
-            triPerSec = camera->buffSize() * Time::fps();
+            world->update();
+            world->projectObjectsInCamera(camera);
 
-            if (b_debugText) {
-                screen->debugText(name + "\n\n X: " +
-                                 std::to_string((camera->eye().x())) + "\n Y: " +
-                                 std::to_string((camera->eye().y())) + "\n Z: " +
-                                 std::to_string((camera->eye().z())) + "\n\n" +
-                                 std::to_string(screen->width()) + "x" +
-                                 std::to_string(screen->height()) + "\n" +
-                                 std::to_string(Time::fps()) +
-                                 " fps \n" + std::to_string((int) triPerSec) + " tris/s");
-            }
+            // draw projected body
+            for (auto &t : camera->sorted())
+                screen->drawTriangle(t);
+
+            _triPerSec = camera->buffSize() * Time::fps();
+
+            printDebugText();
+            gui();
         }
 
-        gui();
         screen->display();
     }
     exit();
@@ -99,5 +69,18 @@ void Engine::exit() {
         screen->close();
     }
     ResourceManager::unloadAllResources();
-    Log::log("Engine::exit(): exit engine (" + std::to_string(screen->width()) + " x " + std::to_string(screen->height()) + ") with name '" + screen->title() + "'.");
+    Log::log("Engine::exit(): exit engine (" + std::to_string(screen->width()) + " x " + std::to_string(screen->height()) + ") with name '" + screen->name() + "'.");
+}
+
+void Engine::printDebugText() const {
+    if (_debugText) {
+        screen->debugText(_name + "\n\n X: " +
+                          std::to_string((camera->eye().x())) + "\n Y: " +
+                          std::to_string((camera->eye().y())) + "\n Z: " +
+                          std::to_string((camera->eye().z())) + "\n\n" +
+                          std::to_string(screen->width()) + "x" +
+                          std::to_string(screen->height()) + "\n" +
+                          std::to_string(Time::fps()) +
+                          " fps \n" + std::to_string((int) _triPerSec) + " _tris/s");
+    }
 }
diff --git a/engine/Engine.h b/engine/Engine.h
index a8814cc..8d14a26 100755
--- a/engine/Engine.h
+++ b/engine/Engine.h
@@ -11,15 +11,19 @@
 #include "utils/Log.h"
 
 class Engine {
+private:
+    std::string _name;
+    double _triPerSec = 0;
+    bool _debugText = true;
+    bool _updateWorld = true;
+
+    void printDebugText() const;
+
 protected:
     std::shared_ptr<Screen> screen;
     std::shared_ptr<World> world;
     std::shared_ptr<Camera> camera;
 
-    double triPerSec = 0;
-
-    bool b_debugText = true;
-    bool b_updateWorld = true;
 public:
     Engine();
 
@@ -28,10 +32,11 @@ public:
     void create(int screenWidth = 1920, int screenHeight = 1080, const std::string& name = "engine", bool verticalSync = true, sf::Color background = sf::Color(255, 255, 255), sf::Uint32 style = sf::Style::Default);
 
     virtual void start() {};
-    virtual void update(double elapsedTime) {};
+    virtual void update() {};
     void exit();
-    void debugText(bool value) { b_debugText = value; }
-    void setUpdateWorld(bool value) { b_updateWorld = value; }
+
+    void setDebugText(bool value) { _debugText = value; }
+    void setUpdateWorld(bool value) { _updateWorld = value; }
 
     virtual void gui(){}
 };
diff --git a/engine/Mesh.cpp b/engine/Mesh.cpp
index cdb58a3..96c3f38 100755
--- a/engine/Mesh.cpp
+++ b/engine/Mesh.cpp
@@ -11,13 +11,9 @@
 
 using namespace std;
 
-Mesh Mesh::operator*(const Matrix4x4 &matrix4X4) const {
-    return Mesh(*this) *= matrix4X4;
-}
-
 Mesh &Mesh::operator*=(const Matrix4x4 &matrix4X4) {
-    for (auto& t : tris)
-        t *= matrix4X4;
+    for (auto& t : _tris)
+        t = t * matrix4X4;
 
     return *this;
 }
@@ -27,7 +23,7 @@ Mesh &Mesh::loadObj(const std::string& filename, const std::string &materials, c
     auto objects = Mesh::LoadObjects(filename, materials, scale);
     for(auto& obj : objects) {
         for (auto &tri : obj->triangles()) {
-            tris.push_back(tri);
+            _tris.push_back(tri);
         }
     }
     return *this;
@@ -38,10 +34,10 @@ Mesh::Mesh(const std::string& filename, const std::string &materials, const Poin
 }
 
 Mesh::Mesh(const vector<Triangle> &tries){
-    tris = tries;
+    _tris = tries;
 }
 
-Mesh::Mesh(const Mesh& mesh) : Animatable(mesh) {
+Mesh::Mesh(const Mesh& mesh) {
     *this = mesh;
 }
 
@@ -50,17 +46,17 @@ Mesh Mesh::Obj(const std::string& filename) {
 }
 
 void Mesh::rotate(const Point4D &r) {
-    p_angle = p_angle + r;
+    _angle = _angle + r;
     *this *= Matrix4x4::Rotation(r);
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), r);
 }
 
 void Mesh::rotate(const Point4D &v, double r) {
     *this *= Matrix4x4::Rotation(v, r);
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(position(), v, r);
 }
 
@@ -71,72 +67,71 @@ void Mesh::scale(const Point4D &s) {
 }
 
 void Mesh::translate(const Point4D &t) {
-    p_position = p_position + t;
+    _position = _position + t;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->translate(t);
 }
 
 Mesh &Mesh::operator=(const Mesh &mesh) {
-    tris = mesh.tris;
-    p_position = mesh.p_position;
-    c_color = mesh.c_color;
+    _tris = mesh._tris;
+    _position = mesh._position;
+    _color = mesh._color;
     return *this;
 }
 
 void Mesh::rotateRelativePoint(const Point4D &s, const Point4D &r) {
-    p_angle = p_angle + r;
+    _angle = _angle + r;
 
     // Translate XYZ by vector r1
-    Point4D r1 = p_position - s;
+    Point4D r1 = _position - s;
     *this *= Matrix4x4::Translation(r1);
 
-    // In translated coordinate system we rotate mesh and position
+    // In translated coordinate system we rotate body and position
     Matrix4x4 rotationMatrix = Matrix4x4::Rotation(r);
     Point4D r2 = rotationMatrix*r1;
     *this *= rotationMatrix;
 
     // After rotation we translate XYZ by vector -r2 and recalculate position
     *this *= Matrix4x4::Translation(-r2);
-    p_position = s + r2;
+    _position = s + r2;
 
-    if(v_attached.empty())
+    if(_attachedObjects.empty())
         return;
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(s, r);
 }
 
 void Mesh::rotateRelativePoint(const Point4D &s, const Point4D &v, double r) {
     // Translate XYZ by vector r1
-    Point4D r1 = p_position - s;
+    Point4D r1 = _position - s;
     *this *= Matrix4x4::Translation(r1);
 
-    // In translated coordinate system we rotate mesh and position
+    // In translated coordinate system we rotate body and position
     Matrix4x4 rotationMatrix = Matrix4x4::Rotation(v, r);
     Point4D r2 = rotationMatrix*r1;
     *this *= rotationMatrix;
 
     // After rotation we translate XYZ by vector -r2 and recalculate position
     *this *= Matrix4x4::Translation(-r2);
-    p_position = s + r2;
+    _position = s + r2;
 
-    for(auto attached : v_attached)
+    for(auto attached : _attachedObjects)
         attached->rotateRelativePoint(s, v, r);
 }
 
 
 void Mesh::translateToPoint(const Point4D &point) {
-    translate(point - p_position);
+    translate(point - _position);
 }
 
 void Mesh::setColor(sf::Color c) {
-    c_color = c;
-    for (auto& t : tris)
-        t.color = c_color;
+    _color = c;
+    for (auto& t : _tris)
+        t = Triangle(t[0], t[1], t[2], _color);
 }
 
-std::vector<std::shared_ptr<Mesh>>
-Mesh::LoadObjects(const string &filename, const string &materials, const Point4D &scale) {
+std::vector<std::shared_ptr<Mesh>> Mesh::LoadObjects(const string &filename, const string &materials, const Point4D &scale) {
     std::vector<std::shared_ptr<Mesh>> objects;
     map<string, sf::Color> maters;
 
@@ -209,8 +204,7 @@ Mesh::LoadObjects(const string &filename, const string &materials, const Point4D
         {
             int f[3];
             s >> junk >> f[0] >> f[1] >> f[2];
-            tris.emplace_back(verts[f[0] - 1], verts[f[1] - 1], verts[f[2] - 1] );
-            tris.back().color = currentColor;
+            tris.emplace_back(verts[f[0] - 1], verts[f[1] - 1], verts[f[2] - 1], currentColor);
         }
     }
 
@@ -225,6 +219,7 @@ Mesh::LoadObjects(const string &filename, const string &materials, const Point4D
 }
 
 Mesh Mesh::LineTo(const Point4D& from, const Point4D& to, double line_width, sf::Color color) {
+
     Mesh line;
 
     Point4D v1 = (to - from).normalized();
@@ -242,7 +237,7 @@ Mesh Mesh::LineTo(const Point4D& from, const Point4D& to, double line_width, sf:
     Point4D p7 = to + v2 * line_width/2.0 + v3 * line_width/2.0;
     Point4D p8 = to + v2 * line_width/2.0 - v3 * line_width/2.0;
 
-    line.tris = {
+    line._tris = {
             { p2, p4, p1 },
             { p2, p3, p4 },
             { p1, p6, p2 },
@@ -259,5 +254,10 @@ Mesh Mesh::LineTo(const Point4D& from, const Point4D& to, double line_width, sf:
 
     line.setColor(color);
 
+    for(auto& triangle : line._tris)
+        triangle = Triangle(Point4D{triangle[0].x(), triangle[0].y(), triangle[0].z(), 1},
+                            Point4D{triangle[1].x(), triangle[1].y(), triangle[1].z(), 1},
+                            Point4D{triangle[2].x(), triangle[2].y(), triangle[2].z(), 1}, line.color());
+
     return line;
 }
diff --git a/engine/Mesh.h b/engine/Mesh.h
index 9b76ee7..2dfcdd2 100755
--- a/engine/Mesh.h
+++ b/engine/Mesh.h
@@ -8,24 +8,16 @@
 #include <vector>
 #include "Triangle.h"
 #include "animation/Animatable.h"
-#include "physics/RigidBody.h"
 #include <SFML/Graphics.hpp>
 #include "Object.h"
 
-class Mesh : public Object, public Animatable, public RigidBody {
+class Mesh : public Object, public Animatable {
 private:
-    // Operations with Matrix4x4
-    [[nodiscard]] Mesh operator*(const Matrix4x4& matrix4X4) const;
-    Mesh& operator*=(const Matrix4x4& matrix4X4);
-
-protected:
-    std::vector<Triangle> tris;
-
+    std::vector<Triangle> _tris;
+    sf::Color _color = sf::Color(255, 245, 194);
     bool _visible = true;
 
-    sf::Color c_color = sf::Color(255, 245, 194);
-
-    std::function<void(const std::string&, std::shared_ptr<Mesh>)> _collisionCallBack;
+    Mesh& operator*=(const Matrix4x4& matrix4X4);
 
 public:
     Mesh() = default;
@@ -37,29 +29,29 @@ public:
 
     Mesh& loadObj(const std::string& filename, const std::string &materials = "", const Point4D& scale = Point4D{1, 1, 1});
 
-    [[nodiscard]] std::vector<Triangle>const &triangles() const { return tris; }
-    [[nodiscard]] std::vector<Triangle>& triangles() override { return tris; }
-    void setTriangles(const std::vector<Triangle>& t) override { tris = t; }
+    [[nodiscard]] std::vector<Triangle>const &triangles() const { return _tris; }
+    [[nodiscard]] std::vector<Triangle>& triangles() override { return _tris; }
+    void setTriangles(const std::vector<Triangle>& t) override { _tris = t; }
 
-    // Translate mesh
+    // Translate body
     void translate(const Point4D& t) override;
     void translateToPoint(const Point4D& point);
-    // Rotate mesh around XYZ axes
+    // Rotate body around XYZ axes
     void rotate(const Point4D& r) override;
-    // Rotate mesh around normalised vector 'v' by 'r' radians
+    // Rotate body around normalised vector 'v' by 'r' radians
     void rotate(const Point4D& v, double r) override;
-    // Rotate mesh around XYZ by (r.x, r.y, r.z) radians relative val 'point4D'
+    // Rotate body around XYZ by (r.x, r.y, r.z) radians relative val 'point4D'
     void rotateRelativePoint(const Point4D& point4D, const Point4D& r) override;
-    // Rotate mesh around normalised vector 'v' by 'r' radians relative val 'point4D'
+    // Rotate body around normalised vector 'v' by 'r' radians relative val 'point4D'
     void rotateRelativePoint(const Point4D& point4D, const Point4D& v, double r) override;
     void scale(const Point4D& s);
 
-    void rotateToAngle(const Point4D& v) { rotate(v - p_angle); }
+    void rotateToAngle(const Point4D& v) { rotate(v - _angle); }
 
-    [[nodiscard]] Point4D position() const override { return p_position; }
-    [[nodiscard]] Point4D angle() const override { return p_angle; }
+    [[nodiscard]] Point4D position() const override { return _position; }
+    [[nodiscard]] Point4D angle() const override { return _angle; }
 
-    [[nodiscard]] sf::Color color() const override { return c_color; }
+    [[nodiscard]] sf::Color color() const override { return _color; }
     void setColor(sf::Color c) override;
 
     Mesh static Obj(const std::string& filename);
@@ -69,9 +61,6 @@ public:
     [[nodiscard]] bool isVisible() const { return _visible; }
 
     std::vector<std::shared_ptr<Mesh>> static LoadObjects(const std::string& filename, const std::string &materials = "", const Point4D& scale = Point4D{1, 1, 1});
-
-    [[nodiscard]] const std::function<void(const std::string&, std::shared_ptr<Mesh>)>& collisionCallBack() const { return _collisionCallBack; }
-    void setCollisionCallBack(const std::function<void(const std::string&, std::shared_ptr<Mesh>)>& f) { _collisionCallBack = f; }
 };
 
 
diff --git a/engine/Object.h b/engine/Object.h
index 0bdc98f..04350da 100755
--- a/engine/Object.h
+++ b/engine/Object.h
@@ -11,10 +11,10 @@
 
 class Object {
 protected:
-    std::vector<std::shared_ptr<Object>> v_attached;
+    std::vector<std::shared_ptr<Object>> _attachedObjects;
 
-    Point4D p_position;
-    Point4D p_angle;
+    Point4D _position;
+    Point4D _angle;
 public:
     Object() = default;
 
@@ -24,11 +24,11 @@ public:
     virtual void rotate(const Point4D& v, double rv) {}
     virtual void rotateRelativePoint(const Point4D& s, const Point4D& v, double r) {}
 
-    [[nodiscard]] Point4D position() const { return p_position; }
-    [[nodiscard]] Point4D angle() const { return p_angle; }
+    [[nodiscard]] Point4D position() const { return _position; }
+    [[nodiscard]] Point4D angle() const { return _angle; }
 
     void attach(std::shared_ptr<Object> object) {
-        v_attached.push_back(std::move(object));
+        _attachedObjects.push_back(object);
     }
 };
 
diff --git a/engine/Plane.cpp b/engine/Plane.cpp
index 1cb9ce3..22f91fe 100755
--- a/engine/Plane.cpp
+++ b/engine/Plane.cpp
@@ -5,35 +5,34 @@
 #include "Plane.h"
 
 Plane::Plane(const Triangle& tri) {
-    triangle = tri;
-    n = tri.norm();
-    p = tri[0];
+    _triangle = tri;
+    _n = tri.norm();
+    _p = tri[0];
 }
 
 Plane::Plane(const Point4D &N, const Point4D &P) {
-    n = N;
-    p = P;
+    _n = N.normalized();
+    _p = P;
 }
 
 Plane::Plane(const Plane &plane) {
-    triangle = plane.triangle;
-    n = plane.n;
-    p = plane.p;
+    _triangle = plane._triangle;
+    _n = plane._n;
+    _p = plane._p;
 }
 
 double Plane::distance(const Point4D &point4D) const {
-    return point4D.dot(n) - p.dot(n);
+    return point4D.dot(_n) - _p.dot(_n);
 }
 
-std::pair<Point4D, double> Plane::intersection(const Point4D &start, const Point4D &end) {
-    double s_dot_n = start.dot(n);
-    double k = (s_dot_n - p.dot(n))/(s_dot_n - end.dot(n));
+std::pair<Point4D, double> Plane::intersection(const Point4D &start, const Point4D &end) const {
+    double s_dot_n = start.dot(_n);
+    double k = (s_dot_n - _p.dot(_n)) / (s_dot_n - end.dot(_n));
     Point4D res = start + (end - start)*k;
     return std::make_pair(res, k);
 }
 
-int Plane::clip(Triangle &tri, Triangle &additional_tri) {
-    n = n.normalized();
+int Plane::clip(Triangle &tri, Triangle &additional_tri) const {
 
     Point4D insidePoints[3];  int inside = 0;
     Point4D outsidePoints[3]; int outside = 0;
@@ -49,20 +48,14 @@ int Plane::clip(Triangle &tri, Triangle &additional_tri) {
     }
 
     if(inside == 0) {
-        tri.clip = Triangle::Skipped;
         return 0;
     }
 
     if(inside == 1) {
         std::pair<Point4D, double> intersect1 = intersection(insidePoints[0], outsidePoints[0]);
         std::pair<Point4D, double> intersect2 = intersection(insidePoints[0], outsidePoints[1]);
-        tri[0] = insidePoints[0];
 
-        tri[1] = intersect1.first;
-
-        tri[2] = intersect2.first;
-
-        tri.clip = Triangle::Cropped;
+        tri = Triangle(insidePoints[0], intersect1.first, intersect2.first, tri.color());
 
         return 1;
     }
@@ -71,20 +64,8 @@ int Plane::clip(Triangle &tri, Triangle &additional_tri) {
         std::pair<Point4D, double> intersect1 = intersection(insidePoints[0], outsidePoints[0]);
         std::pair<Point4D, double> intersect2 = intersection(insidePoints[1], outsidePoints[0]);
 
-        tri[0] = insidePoints[0];
-
-        tri[1] = intersect1.first;
-
-        tri[2] = insidePoints[1];
-
-        additional_tri[0] = intersect1.first;
-
-        additional_tri[1] = intersect2.first;
-
-        additional_tri[2] = insidePoints[1];
-
-        tri.clip = Triangle::Doubled;
-        additional_tri.clip = Triangle::Doubled;
+        tri = Triangle(insidePoints[0], intersect1.first, insidePoints[1], tri.color());
+        additional_tri = Triangle(intersect1.first, intersect2.first, insidePoints[1], tri.color());
 
         return 2;
     }
diff --git a/engine/Plane.h b/engine/Plane.h
index f2fe955..1ae7c1a 100755
--- a/engine/Plane.h
+++ b/engine/Plane.h
@@ -11,24 +11,24 @@
 class Plane {
 private:
     // You can define plane by defining the points in 3D space
-    Triangle triangle;
+    Triangle _triangle;
     // Or by defining normal vector and one val laying on the plane
-    Point4D n = Point4D{0, 0, 1, 0};
-    Point4D p{};
+    Point4D _n = Point4D{0, 0, 1, 0};
+    Point4D _p{};
 public:
-    // A plain with normal vector 'n' and val 'p' lays on the plane
+    // A plain with normal vector '_n' and val '_p' lays on the plane
     Plane() = default;
     Plane(const Point4D& N, const Point4D& P);
     Plane(const Plane& plane);
     explicit Plane(const Triangle& tri);
 
     [[nodiscard]] double distance(const Point4D& point4D) const;
-    // Point4D in space where line ('start' to 'end') intersects plain with normal vector 'n' and val 'p' lays on the plane
-    std::pair<Point4D, double> intersection(const Point4D& start, const Point4D& end);
-    int clip(Triangle& tri, Triangle& additional_tri);
+    // Point4D in space where line ('start' to 'end') intersects plain with normal vector '_n' and val '_p' lays on the plane
+    [[nodiscard]] std::pair<Point4D, double> intersection(const Point4D& start, const Point4D& end) const;
+    int clip(Triangle& tri, Triangle& additional_tri) const;
 
-    [[nodiscard]] Point4D N() const { return n; }
-    [[nodiscard]] Point4D P() const { return p; }
+    [[nodiscard]] Point4D N() const { return _n; }
+    [[nodiscard]] Point4D P() const { return _p; }
 };
 
 
diff --git a/engine/ResourceManager.cpp b/engine/ResourceManager.cpp
index 3eb15e2..38556d5 100755
--- a/engine/ResourceManager.cpp
+++ b/engine/ResourceManager.cpp
@@ -5,7 +5,7 @@
 #include "ResourceManager.h"
 #include <map>
 #include <memory>
-#include <iostream>
+
 namespace ResourceManager
 {
 	namespace
@@ -13,7 +13,6 @@ namespace ResourceManager
 		std::map<std::string, std::shared_ptr<sf::Texture>> _textures;
         std::map<std::string, std::shared_ptr<sf::Font>> _fonts;
 		std::map<std::string, std::shared_ptr<sf::SoundBuffer>> _soundBuffers;
-        std::map<std::string, std::shared_ptr<sf::Shader>> _shaders;
 	}
 
 	void unloadTextures()
@@ -36,18 +35,11 @@ namespace ResourceManager
         _fonts.clear();
 	}
 
-    void unloadShaders() {
-	    for (auto& shader : _shaders)
-	        shader.second.reset();
-	    _shaders.clear();
-	}
-
 	void unloadAllResources()
 	{
 		unloadTextures();
 		unloadSoundBuffers();
         unloadFonts();
-        unloadShaders();
 	}
 
 	std::shared_ptr<sf::Texture> loadTexture(const std::string& filename)
@@ -103,21 +95,4 @@ namespace ResourceManager
 
         return font;
 	}
-
-    std::shared_ptr<sf::Shader> loadShader(const std::string& filename, sf::Shader::Type type) {
-        // If Shader is already loaded - return pointer to it
-        auto it = _shaders.find(filename);
-        if (it != _shaders.end())
-            return it->second;
-
-        // Otherwise - try to load it. If failure - return zero
-        std::shared_ptr<sf::Shader> shader(new sf::Shader);
-        if (!shader->loadFromFile(filename, type))
-            return nullptr;
-
-        // If success - remember and return texture pointer
-        _shaders.emplace(filename, shader);
-
-        return shader;
-	}
 }
diff --git a/engine/ResourceManager.h b/engine/ResourceManager.h
index 0d57216..101a6bf 100755
--- a/engine/ResourceManager.h
+++ b/engine/ResourceManager.h
@@ -25,7 +25,6 @@ namespace ResourceManager
     std::shared_ptr<sf::Texture> loadTexture(const std::string& filename);
     std::shared_ptr<sf::Font> loadFont(const std::string& filename);
     std::shared_ptr<sf::SoundBuffer> loadSoundBuffer(const std::string& filename);
-    std::shared_ptr<sf::Shader> loadShader(const std::string& filename, sf::Shader::Type type);
 };
 
 
diff --git a/engine/Screen.cpp b/engine/Screen.cpp
index fe03007..7831701 100755
--- a/engine/Screen.cpp
+++ b/engine/Screen.cpp
@@ -11,15 +11,15 @@
 
 
 void Screen::open(int screenWidth, int screenHeight, const std::string &name, bool verticalSync, sf::Color background, sf::Uint32 style) {
-    this->name = name;
-    w = screenWidth;
-    h = screenHeight;
-    this->background = background;
+    _name = name;
+    _w = screenWidth;
+    _h = screenHeight;
+    _background = background;
 
     sf::ContextSettings settings;
     settings.antialiasingLevel = 8;
 
-    window.create(sf::VideoMode(w, h), name, style, settings);
+    window.create(sf::VideoMode(_w, _h), name, style, settings);
     window.setVerticalSyncEnabled(verticalSync);
 }
 
@@ -31,44 +31,29 @@ void Screen::display() {
         }
     }
 
-    std::string title = name + " (" + std::to_string(Time::fps()) + " fps)";
+    std::string title = _name + " (" + std::to_string(Time::fps()) + " fps)";
     window.setTitle(title);
 
     window.display();
 }
 
 void Screen::clear() {
-    window.clear(background);
+    window.clear(_background);
 }
 
-void Screen::triangle(const Triangle& triangle)
+void Screen::drawTriangle(const Triangle& triangle)
 {
-    if(vm == Frame || vm == Borders || vm == Xray || vm == Clipped || vm == Transparency || vm == Normals) {
-        sf::Vertex lines[4] =
-                {
-                        sf::Vertex(sf::Vector2f(triangle[0].x(), triangle[0].y()), sf::Color(0, 0, 0, 255)),
-                        sf::Vertex(sf::Vector2f(triangle[1].x(), triangle[1].y()), sf::Color(0, 0, 0, 255)),
-                        sf::Vertex(sf::Vector2f(triangle[2].x(), triangle[2].y()), sf::Color(0, 0, 0, 255)),
-                        sf::Vertex(sf::Vector2f(triangle[0].x(), triangle[0].y()), sf::Color(0, 0, 0, 255))
-                };
-
-        window.draw(lines, 4, sf::LineStrip);
-    }
-    if(vm == Frame || vm == Xray)
-        return; // no texture when we turn on Frame or Xray mode
-
     sf::Vertex tris[3] =
             {
-                    sf::Vertex(sf::Vector2f(triangle[0].x(), triangle[0].y()), triangle.color),
-                    sf::Vertex(sf::Vector2f(triangle[1].x(), triangle[1].y()), triangle.color),
-                    sf::Vertex(sf::Vector2f(triangle[2].x(), triangle[2].y()), triangle.color)
+                    sf::Vertex(sf::Vector2f(triangle[0].x(), triangle[0].y()), triangle.color()),
+                    sf::Vertex(sf::Vector2f(triangle[1].x(), triangle[1].y()), triangle.color()),
+                    sf::Vertex(sf::Vector2f(triangle[2].x(), triangle[2].y()), triangle.color())
             };
     window.draw(tris, 3, sf::Triangles);
 }
 
-void Screen::title(const std::string& title)
-{
-    name = title;
+void Screen::setName(const std::string& title) {
+    _name = title;
 }
 
 bool Screen::isOpen() {
@@ -89,49 +74,28 @@ Point4D Screen::getMousePosition() const {
 }
 
 Point4D Screen::getMouseDisplacement() const {
-    sf::Vector2<int> disp = sf::Mouse::getPosition(window) - sf::Vector2<int>(w/2, h/2);
+    sf::Vector2<int> disp = sf::Mouse::getPosition(window) - sf::Vector2<int>(_w/2, _h/2);
     setMouseInCenter();
     return Point4D(disp.x, disp.y, 0, 0);
 }
 
 void Screen::setMouseInCenter() const {
-    sf::Mouse::setPosition({ w / 2, h / 2 }, window);
+    sf::Mouse::setPosition({ _w / 2, _h / 2 }, window);
 }
 
 void Screen::setMouseCursorVisible(bool visible) {
     window.setMouseCursorVisible(visible);
 }
 
-void Screen::keyboardControl() {
-    // Check all input after this condition please
-    if (!window.hasFocus())
-        return;
-
-    if(isKeyTapped(sf::Keyboard::Num1))
-        setMode(ViewMode::Default);
-    if(isKeyTapped(sf::Keyboard::Num2))
-        setMode(ViewMode::Borders);
-    if(isKeyTapped(sf::Keyboard::Num3))
-        setMode(ViewMode::Transparency);
-    if(isKeyTapped(sf::Keyboard::Num4))
-        setMode(ViewMode::Frame);
-    if(isKeyTapped(sf::Keyboard::Num5))
-        setMode(ViewMode::Xray);
-    if(isKeyTapped(sf::Keyboard::Num6))
-        setMode(ViewMode::Clipped);
-    if(isKeyTapped(sf::Keyboard::Num7))
-        setMode(ViewMode::Normals);
-}
-
 bool Screen::isKeyTapped(sf::Keyboard::Key key) {
     if (!Screen::isKeyPressed(key))
         return false;
 
-    if(tappedKeys.count(key) == 0) {
-        tappedKeys.emplace(key, Time::time());
+    if(_tappedKeys.count(key) == 0) {
+        _tappedKeys.emplace(key, Time::time());
         return true;
-    } else if((Time::time() - tappedKeys[key]) > 0.2) {
-        tappedKeys[key] = Time::time();
+    } else if((Time::time() - _tappedKeys[key]) > 0.2) {
+        _tappedKeys[key] = Time::time();
         return true;
     }
     return false;
@@ -145,11 +109,11 @@ bool Screen::isButtonTapped(sf::Mouse::Button button) {
     if (!Screen::isButtonPressed(button))
         return false;
 
-    if(tappedButtons.count(button) == 0) {
-        tappedButtons.emplace(button, Time::time());
+    if(_tappedButtons.count(button) == 0) {
+        _tappedButtons.emplace(button, Time::time());
         return true;
-    } else if((Time::time() - tappedButtons[button]) > 0.2) {
-        tappedButtons[button] = Time::time();
+    } else if((Time::time() - _tappedButtons[button]) > 0.2) {
+        _tappedButtons[button] = Time::time();
         return true;
     }
     return false;
@@ -159,7 +123,7 @@ bool Screen::isButtonTapped(sf::Mouse::Button button) {
 void Screen::debugText(const std::string& text) {
     sf::Text t;
 
-    t.setFont(*ResourceManager::loadFont(font));
+    t.setFont(*ResourceManager::loadFont(_font));
     t.setString(text);
     t.setCharacterSize(30);
     t.setFillColor(sf::Color::Black);
diff --git a/engine/Screen.h b/engine/Screen.h
index d728ebc..e47c8ef 100755
--- a/engine/Screen.h
+++ b/engine/Screen.h
@@ -13,33 +13,18 @@
 #include "utils/Time.h"
 
 class Screen {
-public:
-    enum ViewMode {
-        Default = 0,
-        Frame,
-        Borders,
-        Xray,
-        Clipped,
-        Transparency,
-        Normals
-    };
 private:
-    int w = 1920;
-    int h = 1080;
+    int _w = 1920;
+    int _h = 1080;
 
-    std::string name;
+    std::string _name;
 
-    sf::Color background;
+    sf::Color _background;
 
-    Screen::ViewMode vm = Screen::ViewMode::Default;
+    std::map<sf::Keyboard::Key, double> _tappedKeys;
+    std::map<sf::Mouse::Button, double> _tappedButtons;
 
-    std::map<sf::Keyboard::Key, double> tappedKeys;
-    std::map<sf::Mouse::Button, double> tappedButtons;
-
-    std::string font = "../engine/fonts/Roboto-Thin.ttf";
-
-    int frame = 0;
-    int scene = 0; // the number of scene
+    std::string _font = "../engine/fonts/Roboto-Thin.ttf";
 
 public:
     sf::RenderWindow window;
@@ -49,10 +34,10 @@ public:
     void display();
     void clear();
 
-    void triangle(const Triangle& triangle );
+    void drawTriangle(const Triangle& triangle);
 
-    void title(const std::string& title);
-    std::string title() const { return name; };
+    void setName(const std::string& title);
+    std::string name() const { return _name; };
 
     bool isOpen();
 
@@ -72,11 +57,6 @@ public:
     void setMouseInCenter() const;
     void setMouseCursorVisible(bool visible);
 
-    void setMode(ViewMode mode) { vm = mode; }
-    [[nodiscard]] ViewMode mode() const { return vm; }
-
-    void keyboardControl();
-
     void debugText(const std::string& text);
 };
 
diff --git a/engine/Triangle.cpp b/engine/Triangle.cpp
index bb589ef..5cad1ba 100755
--- a/engine/Triangle.cpp
+++ b/engine/Triangle.cpp
@@ -5,76 +5,55 @@
 #include "Triangle.h"
 
 Triangle::Triangle () {
-    p[0] = Point4D{0,0,0,1};
-    p[1] = Point4D{0,0,0,1};
-    p[2] = Point4D{0,0,0,1};
+    _p[0] = Point4D{0, 0, 0, 1};
+    _p[1] = Point4D{0, 0, 0, 1};
+    _p[2] = Point4D{0, 0, 0, 1};
 }
 
-Triangle::Triangle(const Point4D& p1, const Point4D& p2, const Point4D& p3, double w) {
-    p[0] = Point4D{p1.x(), p1.y(), p1.z(), w};
-    p[1] = Point4D{p2.x(), p2.y(), p2.z(), w};
-    p[2] = Point4D{p3.x(), p3.y(), p3.z(), w};
+Triangle::Triangle(const Point4D& p1, const Point4D& p2, const Point4D& p3, sf::Color color) {
+    _p[0] = p1;
+    _p[1] = p2;
+    _p[2] = p3;
+    _color = color;
 }
 
 Triangle Triangle::operator*(const Matrix4x4 &matrix4X4) const {
-    return Triangle(*this) *= matrix4X4;
-}
+    Triangle res(*this);
 
-Triangle &Triangle::operator*=(const Matrix4x4 &matrix4X4) {
-    p[0] = matrix4X4 * p[0];
-    p[1] = matrix4X4 * p[1];
-    p[2] = matrix4X4 * p[2];
+    res._p[0] = matrix4X4 * _p[0];
+    res._p[1] = matrix4X4 * _p[1];
+    res._p[2] = matrix4X4 * _p[2];
 
-    return *this;
+    return res;
 }
 
 Point4D Triangle::norm() const {
 
-    Point4D v1 = p[1] - p[0];
-    Point4D v2 = p[2] - p[0];
+    Point4D v1 = _p[1] - _p[0];
+    Point4D v2 = _p[2] - _p[0];
 
     return v1.cross3D(v2).normalized();
 }
 
 Point4D Triangle::operator[](int i) const {
-    return p[i];
-}
-
-Point4D &Triangle::operator[](int i) {
-    return p[i];
-}
-
-Point4D Triangle::pos() const {
-    return (p[0] + p[1] + p[2])/3.0;
+    return _p[i];
 }
 
 Triangle::Triangle(const Triangle &triangle) {
-    clip = triangle.clip;
-    color = triangle.color;
-    p[0] = triangle[0];
-    p[1] = triangle[1];
-    p[2] = triangle[2];
+    _color = triangle._color;
+    _p[0] = triangle[0];
+    _p[1] = triangle[1];
+    _p[2] = triangle[2];
 }
 
 bool Triangle::isPointInside(const Point4D &point) const {
     Point4D triangleNorm = norm();
 
-    double dot1 = (point - p[0]).cross3D(p[1] - p[0]).dot(triangleNorm);
-    double dot2 = (point - p[1]).cross3D(p[2] - p[1]).dot(triangleNorm);
-    double dot3 = (point - p[2]).cross3D(p[0] - p[2]).dot(triangleNorm);
+    double dot1 = (point - _p[0]).cross3D(_p[1] - _p[0]).dot(triangleNorm);
+    double dot2 = (point - _p[1]).cross3D(_p[2] - _p[1]).dot(triangleNorm);
+    double dot3 = (point - _p[2]).cross3D(_p[0] - _p[2]).dot(triangleNorm);
 
     if((dot1 >= 0 && dot2 >= 0 && dot3 >= 0) || (dot1 <= 0 && dot2 <= 0 && dot3 <= 0))
         return true;
     return false;
 }
-
-Triangle &Triangle::operator=(const Triangle &triangle) {
-    if(&triangle != this) {
-        clip = triangle.clip;
-        color = triangle.color;
-        p[0] = triangle[0];
-        p[1] = triangle[1];
-        p[2] = triangle[2];
-    }
-    return *this;
-}
diff --git a/engine/Triangle.h b/engine/Triangle.h
index 3efc35c..a5580dd 100755
--- a/engine/Triangle.h
+++ b/engine/Triangle.h
@@ -10,34 +10,25 @@
 #include <SFML/Graphics.hpp>
 
 class Triangle {
+private:
+    sf::Color _color;
+    Point4D _p[3];
+
 public:
-    // This is for clipping debug: you can distinguish how this triangle was clipped
-    enum ClipMode {
-        None = 0,
-        Cropped,
-        Doubled,
-        Skipped
-    };
-    ClipMode clip = None;
-    sf::Color color;
-    Point4D p[3];
 
     Triangle ();
     Triangle (const Triangle& triangle);
-    Triangle (const Point4D& p1, const Point4D& p2, const Point4D& p3, double w = 1);
-    Triangle& operator=(const Triangle& triangle);
+    Triangle (const Point4D& p1, const Point4D& p2, const Point4D& p3, sf::Color color = {0, 0, 0});
 
     [[nodiscard]] Point4D operator[] (int i) const;
-    [[nodiscard]] Point4D& operator[] (int i);
-
     [[nodiscard]] Point4D norm() const;
 
     // Operations with Matrix4x4
     [[nodiscard]] Triangle operator*(const Matrix4x4& matrix4X4) const;
-    Triangle& operator*=(const Matrix4x4& matrix4X4);
-    [[nodiscard]] Point4D pos() const;
 
     [[nodiscard]] bool isPointInside(const Point4D& point) const;
+
+    [[nodiscard]] sf::Color color() const { return _color; }
 };
 
 
diff --git a/engine/World.cpp b/engine/World.cpp
index f52df29..20f7baa 100755
--- a/engine/World.cpp
+++ b/engine/World.cpp
@@ -2,35 +2,27 @@
 // Created by Иван Ильин on 13.01.2021.
 //
 
-#include <fstream>
-#include <sstream>
 #include "World.h"
 #include "utils/Log.h"
 #include "Plane.h"
+#include "physics/Solver.h"
 
 using namespace std;
 
-void World::addMesh(std::shared_ptr<Mesh> mesh, const string &name) {
-    _objects.emplace(name, mesh);
-    Log::log("World::addMesh(): inserted mesh '" + name + "' with " + std::to_string(_objects[name]->triangles().size()) + " tris.");
-
+void World::addBody(std::shared_ptr<RigidBody> body, const string &name) {
+    _objects.emplace(name, body);
+    Log::log("World::addBody(): inserted body '" + name + "' with " + std::to_string(_objects[name]->triangles().size()) + " _tris.");
 }
 
-void World::loadObj(const string &name, const string &filename,const std::string &materials, const Point4D& scale) {
-    _objects.emplace(name, std::make_shared<Mesh>(filename, materials, scale));
-    Log::log("World::loadObj(): inserted mesh from " + filename + " with name '" + name + "' with " + std::to_string(_objects[name]->triangles().size()) + " tris.");
+void World::loadBody(const string &name, const string &filename, const std::string &materials, const Point4D& scale) {
+    _objects.emplace(name, std::make_shared<RigidBody>(Mesh(filename, materials, scale)));
+    Log::log("World::loadBody(): inserted body from " + filename + " with name '" + name + "' with " + std::to_string(_objects[name]->triangles().size()) + " _tris.");
 }
 
-void World::removeMesh(const string &name) {
+void World::removeBody(const string &name) {
     _objToRemove.push_back(name);
 }
 
-std::shared_ptr<Mesh> World::operator[](const string &name) {
-    if(_objects.count(name) == 0)
-        Log::log("World::operator[]: mesh '" + name + "' does not exist.");
-    return _objects.find(name)->second;
-}
-
 std::pair<Point4D, string> World::rayCast(const Point4D& from, const Point4D& to) {
 
     std::pair<Point4D, string> result{Point4D{0, 0,0, -1}, ""};
@@ -41,7 +33,7 @@ std::pair<Point4D, string> World::rayCast(const Point4D& from, const Point4D& to
             continue;
 
         for(auto& tri : object.second->triangles()) {
-            Triangle tri_translated(tri[0] + object.second->position(), tri[1] + object.second->position(), tri[2] + object.second->position(), 0);
+            Triangle tri_translated(tri[0] + object.second->position(), tri[1] + object.second->position(), tri[2] + object.second->position());
 
             Plane plane(tri_translated);
             auto intersection = plane.intersection(from, to);
@@ -59,23 +51,63 @@ void World::loadMap(const string &filename, const string &name, const Point4D &s
     auto objs = Mesh::LoadObjects(filename, materials, scale);
     for(int i = 0; i < objs.size(); i++) {
         string meshName = name + "_" + to_string(i);
-        addMesh(objs[i], meshName);
+        addBody(std::make_shared<RigidBody>(*objs[i]), meshName);
     }
 }
 
 void World::garbageCollector() {
     for(auto& obj : _objToRemove) {
         if(_objects.erase(obj) > 0)
-            Log::log("World::garbageCollector(): removed mesh '" + obj + "'");
+            Log::log("World::garbageCollector(): removed body '" + obj + "'");
         else
-            Log::log("World::garbageCollector(): cannot remove mesh '" + obj + "': mesh does not exist.");
+            Log::log("World::garbageCollector(): cannot remove body '" + obj + "': body does not exist.");
     }
     _objToRemove.clear();
 }
 
-void World::removeMeshInstantly(const string &name) {
+void World::removeBodyInstantly(const string &name) {
     if(_objects.erase(name) > 0)
-        Log::log("World::removeMeshInstantly(): removed mesh '" + name + "'");
+        Log::log("World::removeBodyInstantly(): removed body '" + name + "'");
     else
-        Log::log("World::removeMeshInstantly(): cannot remove mesh '" + name + "': mesh does not exist.");
+        Log::log("World::removeBodyInstantly(): cannot remove body '" + name + "': body does not exist.");
+}
+
+void World::checkCollision(const std::string& body) {
+    if (_objects[body]->isCollision()) {
+
+        _objects[body]->setInCollision(false);
+
+        for (auto &obj : _objects) {
+            if(obj.first != body) {
+                std::pair<bool, Simplex> gjk = _objects[body]->checkGJKCollision(obj.second);
+                if (gjk.first) {
+                    if (obj.second->isCollider()) {
+                        CollisionPoint epa = _objects[body]->EPA(gjk.second, obj.second);
+                        Solver::solveCollision(_objects[body], obj.second, epa);
+                    }
+                    if (_objects[body]->collisionCallBack() != nullptr)
+                        _objects[body]->collisionCallBack()(obj.first, obj.second);
+                }
+            }
+        }
+    }
+}
+
+void World::update() {
+    for (auto &m : _objects) {
+        m.second->a_update();
+        m.second->updatePhysicsState();
+        checkCollision(m.first);
+    }
+}
+
+void World::projectObjectsInCamera(std::shared_ptr<Camera> camera) {
+    for (auto &m : _objects)
+        camera->project(m.second);
+}
+
+std::shared_ptr<RigidBody> World::body(const string &name) {
+    if(_objects.count(name) == 0)
+        Log::log("World::body: mesh '" + name + "' does not exist.");
+    return _objects.find(name)->second;
 }
diff --git a/engine/World.h b/engine/World.h
index 392fe82..93855a3 100755
--- a/engine/World.h
+++ b/engine/World.h
@@ -6,25 +6,26 @@
 #define ENGINE_WORLD_H
 
 #include <map>
-#include "Mesh.h"
+#include "Camera.h"
+#include "physics/RigidBody.h"
 
 class World {
 private:
-    std::map<std::string, std::shared_ptr<Mesh>> _objects;
-
+    std::map<std::string, std::shared_ptr<RigidBody>> _objects;
     std::vector<std::string> _objToRemove;
 public:
     World() = default;
 
-    [[nodiscard]] std::shared_ptr<Mesh> operator[] (const std::string& name);
+    void checkCollision(const std::string& body);
+    void update();
+    void projectObjectsInCamera(std::shared_ptr<Camera> camera);
 
-    [[nodiscard]] std::map<std::string, std::shared_ptr<Mesh>>& objects() { return _objects; }
-
-    void addMesh(std::shared_ptr<Mesh> mesh, const std::string& name = "");
-    void removeMesh(const std::string& name);
-    void removeMeshInstantly(const std::string& name);
+    void addBody(std::shared_ptr<RigidBody> mesh, const std::string& name = "");
+    std::shared_ptr<RigidBody> body(const std::string& name);
+    void removeBody(const std::string& name);
+    void removeBodyInstantly(const std::string& name);
     void garbageCollector();
-    void loadObj(const std::string &name, const std::string &filename,const std::string &materials = "", const Point4D& scale = Point4D{1, 1, 1});
+    void loadBody(const std::string &name, const std::string &filename, const std::string &materials = "", const Point4D& scale = Point4D{1, 1, 1});
 
     // rayCast returns pair of Point4D and std::string:
     // 1) Point4D is point of collision (the last coordinate is -1 if there are no collisions)
diff --git a/engine/animation/Animation.h b/engine/animation/Animation.h
index 0ec26fa..d22f0dc 100755
--- a/engine/animation/Animation.h
+++ b/engine/animation/Animation.h
@@ -34,7 +34,7 @@ protected:
     double _duration = 0;
     bool _started = false;
     LoopOut _looped = None;
-    // p - animation progress
+    // _p - animation progress
     double _p = 0;
     double _dp = 0;
 
diff --git a/engine/gui/Window.cpp b/engine/gui/Window.cpp
index 63b611a..ac31507 100755
--- a/engine/gui/Window.cpp
+++ b/engine/gui/Window.cpp
@@ -16,7 +16,7 @@ void Window::addButton(int x, int y, int w, int h, std::function<void()> click,
 
 void Window::update(std::shared_ptr<Screen> screen) {
 
-    screen->title(s_name);
+    screen->setName(s_name);
     screen->window.draw(back);
 
     Point4D mousePos = screen->getMousePosition();
diff --git a/engine/gui/Window.h b/engine/gui/Window.h
index d0957c9..975851e 100755
--- a/engine/gui/Window.h
+++ b/engine/gui/Window.h
@@ -21,7 +21,7 @@ private:
 
     Point4D prevMousePosition;
 public:
-    explicit Window(std::string name = "Menu", std::string  backTexture = "") : s_name(std::move(name)), s_backTexture(std::move(backTexture)){}
+    explicit Window(std::string  name = "Menu", std::string  backTexture = "") : s_name(std::move(name)), s_backTexture(std::move(backTexture)){}
 
     void addButton(int x, int y, int w, int h,
                    std::function<void()> click,
diff --git a/engine/physics/RigidBody.cpp b/engine/physics/RigidBody.cpp
index 5290e64..33677b1 100755
--- a/engine/physics/RigidBody.cpp
+++ b/engine/physics/RigidBody.cpp
@@ -13,7 +13,8 @@ Point4D RigidBody::_findFurthestPoint(const Point4D& direction) {
     Point4D maxPoint = {};
     auto maxDistance = (double)-INFINITY;
     for(auto& tri : triangles()){
-        for(auto point : tri.p){
+        for(int i = 0; i < 3; i++){
+            Point4D point = tri[i];
 
             point = point + position();
 
@@ -302,18 +303,22 @@ void RigidBody::AddIfUniqueEdge(std::vector<std::pair<size_t, size_t>>& edges, c
 }
 
 void RigidBody::updatePhysicsState() {
-    translate(p_velocity * Time::deltaTime());
-    p_velocity = p_velocity + p_acceleration * Time::deltaTime();
+    translate(_velocity * Time::deltaTime());
+    _velocity = _velocity + _acceleration * Time::deltaTime();
 }
 
 void RigidBody::setVelocity(const Point4D& velocity) {
-    p_velocity = velocity;
+    _velocity = velocity;
 }
 
 void RigidBody::addVelocity(const Point4D &velocity) {
-    p_velocity = p_velocity + velocity;
+    _velocity = _velocity + velocity;
 }
 
 void RigidBody::setAcceleration(const Point4D& acceleration) {
-    p_acceleration = acceleration;
+    _acceleration = acceleration;
+}
+
+RigidBody::RigidBody(const Mesh &mesh) : Mesh(mesh) {
+
 }
diff --git a/engine/physics/RigidBody.h b/engine/physics/RigidBody.h
index 96ca227..52c8379 100755
--- a/engine/physics/RigidBody.h
+++ b/engine/physics/RigidBody.h
@@ -10,6 +10,7 @@
 #include "../utils/Point4D.h"
 #include "../Triangle.h"
 #include "Simplex.h"
+#include "Mesh.h"
 
 struct CollisionPoint {
     Point4D a; // Furthest point of a into b
@@ -19,20 +20,13 @@ struct CollisionPoint {
     bool hasCollision;
 };
 
-class RigidBody {
-protected:
-    Point4D p_velocity;
-    Point4D p_acceleration;
-
-    bool _collision = false;
-    bool _isCollider = true;
-
-    bool _inCollision = false;
-    Point4D _collisionNormal;
-
+class RigidBody : public Mesh {
+private:
     Point4D _findFurthestPoint(const Point4D& direction);
     Point4D _support(std::shared_ptr<RigidBody> obj, const Point4D& direction);
 
+    std::function<void(const std::string&, std::shared_ptr<RigidBody>)> _collisionCallBack;
+
     static bool _nextSimplex(Simplex& points, Point4D& direction);
     static bool _line(Simplex& points, Point4D& direction);
     static bool _triangle(Simplex& points, Point4D& direction);
@@ -41,9 +35,19 @@ protected:
     static std::pair<std::vector<Point4D>, size_t> GetFaceNormals(const std::vector<Point4D>& polytope, const std::vector<size_t>&  faces);
     static void AddIfUniqueEdge(std::vector<std::pair<size_t, size_t>>& edges, const std::vector<size_t>& faces, size_t a, size_t b);
 
+protected:
+    Point4D _velocity;
+    Point4D _acceleration;
+
+    bool _collision = false;
+    bool _isCollider = true;
+
+    bool _inCollision = false;
+    Point4D _collisionNormal;
+
 public:
     RigidBody() = default;
-    virtual ~RigidBody() = default;
+    explicit RigidBody(const Mesh& mesh);
 
     std::pair<bool, Simplex> checkGJKCollision(std::shared_ptr<RigidBody> obj);
     CollisionPoint EPA(const Simplex& simplex, std::shared_ptr<RigidBody> obj);
@@ -56,19 +60,16 @@ public:
     void setCollision(bool c) { _collision= c; }
     void setCollider(bool c) { _isCollider = c; }
 
-    [[nodiscard]] virtual std::vector<Triangle>& triangles() = 0;
-
-    [[nodiscard]] virtual Point4D position() const = 0;
-    virtual void translate(const Point4D& dv) = 0;
-    virtual void rotate(const Point4D& r) = 0;
-
     void updatePhysicsState();
 
     void setVelocity(const Point4D& velocity);
     void addVelocity(const Point4D& velocity);
     void setAcceleration(const Point4D& acceleration);
 
-    [[nodiscard]] Point4D velocity() const { return p_velocity; }
+    [[nodiscard]] Point4D velocity() const { return _velocity; }
+
+    [[nodiscard]] const std::function<void(const std::string&, std::shared_ptr<RigidBody>)>& collisionCallBack() const { return _collisionCallBack; }
+    void setCollisionCallBack(const std::function<void(const std::string&, std::shared_ptr<RigidBody>)>& f) { _collisionCallBack = f; }
 };
 
 
diff --git a/engine/utils/Point4D.cpp b/engine/utils/Point4D.cpp
index 69980d5..fea6de0 100755
--- a/engine/utils/Point4D.cpp
+++ b/engine/utils/Point4D.cpp
@@ -46,7 +46,7 @@ Point4D Point4D::operator-(const Point4D& point4D) const {
 
 double Point4D::dot(const Point4D& point4D) const
 {
-    return point4D.x() * x() + point4D.y() * y() + point4D.z() * z() + point4D.w() * w();
+    return point4D.x() * x() + point4D.y() * y() + point4D.z() * z();
 }
 [[nodiscard]] Point4D Point4D::cross3D(const Point4D& point4D) const {
     return Point4D {y() * point4D.z() - point4D.y() * z(),
diff --git a/main.cpp b/main.cpp
index 0865751..8c9cc2a 100755
--- a/main.cpp
+++ b/main.cpp
@@ -75,7 +75,7 @@ public:
     Shooter() = default;
 
     void start() override;
-    void update(double elapsedTime) override;
+    void update() override;
 
     void gui() override;
 
@@ -84,7 +84,7 @@ public:
 
 void Shooter::start() {
     // This code executed once in the beginning:
-    debugText(false);
+    setDebugText(false);
 
     screen->setMouseCursorVisible(true);
 
@@ -100,7 +100,7 @@ void Shooter::start() {
 
     setUpdateWorld(false);
 
-    world->addMesh(player, player->name());
+    world->addBody(player, player->name());
 
     player->setDamagePlayerCallBack([this] (sf::Uint16 targetId, double damage) { client->damagePlayer(targetId, damage); });
     player->setTakeBonusCallBack([this] (const string& bonusName) { client->takeBonus(bonusName); });
@@ -132,7 +132,7 @@ void Shooter::start() {
     }
 }
 
-void Shooter::update(double elapsedTime) {
+void Shooter::update() {
     // This code executed every time step:
 
     server->update();
@@ -148,7 +148,7 @@ void Shooter::update(double elapsedTime) {
     }
 
     if(inGame) {
-        screen->title("Shooter");
+        screen->setName("Shooter");
         player->update();
     } else {
         mainMenu.update(screen);
@@ -166,19 +166,16 @@ void Shooter::update(double elapsedTime) {
 
 void Shooter::gui() {
 
-    if(inGame) {
-        // aim
-        sf::Sprite sprite;
-        sprite.setTexture(*ResourceManager::loadTexture("../textures/gui.png"));
-        sprite.setTextureRect(sf::IntRect(243, 3, 9, 9));
-        sprite.scale(3, 3);
-        sprite.setPosition(screen->width() / 2.0 - 27.0/2.0, screen->height() / 2 - 27.0/2.0);
-        sprite.setColor(sf::Color(0,0,0, 200));
-        screen->window.draw(sprite);
+    sf::Sprite sprite;
+    sprite.setTexture(*ResourceManager::loadTexture("../textures/gui.png"));
+    sprite.setTextureRect(sf::IntRect(243, 3, 9, 9));
+    sprite.scale(3, 3);
+    sprite.setPosition(screen->width() / 2.0 - 27.0/2.0, screen->height() / 2 - 27.0/2.0);
+    sprite.setColor(sf::Color(0,0,0, 200));
+    screen->window.draw(sprite);
 
-        // health player stats
-        player->drawStats();
-    }
+    // health player stats
+    player->drawStats();
 }
 
 void Shooter::play() {
diff --git a/weapon/Shotgun.cpp b/weapon/Shotgun.cpp
index 5be64ae..25617a1 100755
--- a/weapon/Shotgun.cpp
+++ b/weapon/Shotgun.cpp
@@ -41,13 +41,13 @@ Shotgun::processFire(std::shared_ptr<World> world, std::shared_ptr<Camera> camer
         string traceName = _name + "_trace_nr_" + std::to_string(fireTraces++);
         Point4D from = _objects[_name + "_" + to_string(9)]->position() +
                        _objects[_name + "_" + to_string(9)]->triangles()[0][0];
-        world->addMesh(make_shared<Mesh>(Mesh::LineTo(from, to, 0.05)), traceName);
-        (*world)[traceName]->setCollider(false);
+        world->addBody(make_shared<RigidBody>(Mesh::LineTo(from, to, 0.05)), traceName);
+        world->body(traceName)->setCollider(false);
 
         // remove trace line after some time
-        (*world)[traceName]->a_color("color_trace", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
-        (*world)["map_0"]->a_function(traceName + "delete", [world, traceName]() { deleteTrace(world, traceName); },
-                                          1, 2);
+        world->body(traceName)->a_color("color_trace", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
+        world->body("map_0")->a_function(traceName + "delete", [world, traceName]() { deleteTrace(world, traceName); },
+                                         1, 2);
         addTraceCallBack(from, to);
     }
 
diff --git a/weapon/Weapon.cpp b/weapon/Weapon.cpp
index 13dca7c..478724a 100755
--- a/weapon/Weapon.cpp
+++ b/weapon/Weapon.cpp
@@ -14,13 +14,16 @@ Weapon::Weapon(const std::string& weaponName, const std::string& objFileName, co
     auto objs = Mesh::LoadObjects(objFileName, matFileName, scale);
     for(int i = 0; i < objs.size(); i++) {
         string meshName = _name + "_" + to_string(i);
-        objs[i]->setCollider(false);
+
+        RigidBody obj(*objs[i]);
+
+        obj.setCollider(false);
 
         //transforms
-        objs[i]->rotate(rotate);
-        objs[i]->translate(translate);
+        obj.rotate(rotate);
+        obj.translate(translate);
 
-        _objects.insert({meshName, objs[i]});
+        _objects.insert({meshName, std::make_shared<RigidBody>(obj)});
     }
     noAmmoSound.setBuffer(*ResourceManager::loadSoundBuffer("../sound/weapons/no_ammo.ogg"));
 }
@@ -62,13 +65,13 @@ void Weapon::reload() {
 
 void Weapon::addToWorld(shared_ptr<World> world) {
     for(auto& obj : _objects) {
-        world->addMesh(obj.second, obj.first);
+        world->addBody(obj.second, obj.first);
     }
 }
 
 void Weapon::removeFromWorld(shared_ptr<World> world) {
     for(auto& obj : _objects) {
-        world->removeMeshInstantly(obj.first);
+        world->removeBodyInstantly(obj.first);
     }
 }
 
@@ -90,7 +93,7 @@ void Weapon::translate(const Point4D &point4D) {
 }
 
 void Weapon::deleteTrace(shared_ptr<World> world, const std::string& traceName) {
-    world->removeMesh(traceName);
+    world->removeBody(traceName);
 }
 
 void Weapon::rotateRelativePoint(const Point4D &point4D, const Point4D &v, double val) {
@@ -114,12 +117,12 @@ std::map<std::string, double> Weapon::processFire(shared_ptr<World> world, share
     Point4D to = rayCast.first.w() == -1 ? camera->position() + camera->lookAt() * 1000 + randV: rayCast.first;
     string traceName = _name + "_trace_nr_" + std::to_string(fireTraces++);
     Point4D from = _objects[_name + "_" + to_string(_objects.size()-1)]->position() + _objects[_name + "_" + to_string(_objects.size()-1)]->triangles()[0][0];
-    world->addMesh(make_shared<Mesh>(Mesh::LineTo(from, to, 0.05)), traceName);
-    (*world)[traceName]->setCollider(false);
+    world->addBody(make_shared<RigidBody>(Mesh::LineTo(from, to, 0.05)), traceName);
+    world->body(traceName)->setCollider(false);
 
     // remove trace line after some time
-    (*world)[traceName]->a_color("color_trace", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
-    (*world)["Player_im"]->a_function(traceName + "delete", [world, traceName](){deleteTrace(world, traceName); }, 1, 2);
+    world->body(traceName)->a_color("color_trace", {255, 255, 255, 0}, 1, Animation::None, Animation::linear);
+    world->body("Player_im")->a_function(traceName + "delete", [world, traceName](){deleteTrace(world, traceName); }, 1, 2);
 
     addTraceCallBack(from, to);
 
diff --git a/weapon/Weapon.h b/weapon/Weapon.h
index cdfb345..0e33506 100755
--- a/weapon/Weapon.h
+++ b/weapon/Weapon.h
@@ -28,7 +28,7 @@ protected:
     double _spreading = 2.0;
 
     std::string _name = "Weapon_name";
-    std::map<std::string, std::shared_ptr<Mesh>> _objects;
+    std::map<std::string, std::shared_ptr<RigidBody>> _objects;
 
     double _lastFireTime = -INFINITY;
     double _lastReloadTime = -INFINITY;