diff --git a/ToyEngine/Shaders/pbr.comp b/ToyEngine/Shaders/pbr.comp
index d8cacd6..4bd8675 100644
--- a/ToyEngine/Shaders/pbr.comp
+++ b/ToyEngine/Shaders/pbr.comp
@@ -101,6 +101,7 @@ const int pcfRadius = 3;
 float getShadowFromLayer(vec3 fragPosWorldSpace, vec3 normal,int layer)
 {
     float normalBias = 1.2*4. /** (1+pcfRadius)*/ * shadowBiases[layer]*max((1.0 - dot(normal, mainLightDirection)), 0.1)/textureSize(gShadowMap, 0).x;
+	normalBias = max(normalBias, 0.05);
     vec4 fragPosLightSpace = lightSpaceMatrices[layer] * vec4(fragPosWorldSpace+normal*normalBias, 1.0);
     // perform perspective divide
     vec3 projCoords = fragPosLightSpace.xyz / fragPosLightSpace.w;
diff --git a/ToyEngine/ToyEngine.vcxproj b/ToyEngine/ToyEngine.vcxproj
index 9d085e7..02df996 100644
--- a/ToyEngine/ToyEngine.vcxproj
+++ b/ToyEngine/ToyEngine.vcxproj
@@ -24,11 +24,13 @@
     <ClInclude Include="src\Animator.h" />
     <ClInclude Include="src\Bone.h" />
     <ClInclude Include="src\Camera.h" />
+    <ClInclude Include="src\DemoWorld.h" />
     <ClInclude Include="src\IblUtils.h" />
     <ClInclude Include="src\Light.h" />
     <ClInclude Include="src\MainWindow.h" />
     <ClInclude Include="src\Mesh.h" />
     <ClInclude Include="src\Model.h" />
+    <ClInclude Include="src\Particle.h" />
     <ClInclude Include="src\RenderPass.h" />
     <ClInclude Include="src\Shader.h" />
     <ClInclude Include="src\World.h" />
@@ -39,6 +41,7 @@
     <ClCompile Include="src\Animator.cpp" />
     <ClCompile Include="src\Bone.cpp" />
     <ClCompile Include="src\Camera.cpp" />
+    <ClCompile Include="src\DemoWorld.cpp" />
     <ClCompile Include="src\gl.c" />
     <ClCompile Include="src\IblUtils.cpp" />
     <ClCompile Include="src\Light.cpp" />
@@ -46,6 +49,7 @@
     <ClCompile Include="src\MainWindow.cpp" />
     <ClCompile Include="src\Mesh.cpp" />
     <ClCompile Include="src\Model.cpp" />
+    <ClCompile Include="src\Particle.cpp" />
     <ClCompile Include="src\RenderPass.cpp" />
     <ClCompile Include="src\World.cpp" />
   </ItemGroup>
@@ -163,6 +167,9 @@
       <LanguageStandard>stdcpp20</LanguageStandard>
       <LanguageStandard_C>stdc17</LanguageStandard_C>
       <MultiProcessorCompilation>true</MultiProcessorCompilation>
+      <Optimization>MaxSpeed</Optimization>
+      <FavorSizeOrSpeed>Speed</FavorSizeOrSpeed>
+      <BasicRuntimeChecks>Default</BasicRuntimeChecks>
     </ClCompile>
     <Link>
       <SubSystem>Console</SubSystem>
diff --git a/ToyEngine/ToyEngine.vcxproj.filters b/ToyEngine/ToyEngine.vcxproj.filters
index 51abfa2..467f3cd 100644
--- a/ToyEngine/ToyEngine.vcxproj.filters
+++ b/ToyEngine/ToyEngine.vcxproj.filters
@@ -57,6 +57,12 @@
     <ClInclude Include="src\World.h">
       <Filter>头文件</Filter>
     </ClInclude>
+    <ClInclude Include="src\Particle.h">
+      <Filter>头文件</Filter>
+    </ClInclude>
+    <ClInclude Include="src\DemoWorld.h">
+      <Filter>头文件</Filter>
+    </ClInclude>
   </ItemGroup>
   <ItemGroup>
     <ClCompile Include="src\gl.c">
@@ -101,6 +107,12 @@
     <ClCompile Include="src\World.cpp">
       <Filter>源文件</Filter>
     </ClCompile>
+    <ClCompile Include="src\Particle.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
+    <ClCompile Include="src\DemoWorld.cpp">
+      <Filter>源文件</Filter>
+    </ClCompile>
   </ItemGroup>
   <ItemGroup>
     <None Include="Shaders\brdf_lut.comp">
diff --git a/ToyEngine/src/Actor.cpp b/ToyEngine/src/Actor.cpp
index 31a3f5c..fbdf4fc 100644
--- a/ToyEngine/src/Actor.cpp
+++ b/ToyEngine/src/Actor.cpp
@@ -1,17 +1,29 @@
 #include "Actor.h"
 #include "MainWindow.h"
 
+Actor::Actor()
+	: gl(MainWindow::getGLContext())
+	, model(gl)
+	, animator(gl, animation.get())
+{
+}
+
 Actor::Actor(const std::string& path)
 	: gl(MainWindow::getGLContext())
 	, model(gl, path)
-	, danceAnimation(path, &model)
-	, animator(gl, &danceAnimation)
+	, animation(std::make_unique<Animation>(path, &model))
+	, animator(gl, animation->available() ? animation.get() : nullptr)
 {
 }
 
-void Actor::tick(float deltaTime)
+void Actor::logicalTick(float deltaTime)
 {
-	animator.UpdateAnimation(deltaTime);
+	animator.updateAnimation(deltaTime);
+}
+
+void Actor::rendererTick(float deltaTime)
+{
+
 }
 
 void Actor::draw(Shader& shader)
@@ -39,6 +51,21 @@ void Actor::setRotaion(const glm::quat& rotation)
 	updateTransform();
 }
 
+glm::vec3 Actor::getPosition()
+{
+	return position;
+}
+
+glm::vec3 Actor::getScale()
+{
+	return scale;
+}
+
+glm::quat Actor::getRotation()
+{
+	return rotation;
+}
+
 std::pair<glm::vec3, glm::vec3> Actor::getAABB()
 {
 	return model.getAABB();
diff --git a/ToyEngine/src/Actor.h b/ToyEngine/src/Actor.h
index e89fd04..e13a621 100644
--- a/ToyEngine/src/Actor.h
+++ b/ToyEngine/src/Actor.h
@@ -7,21 +7,32 @@
 class Actor
 {
 public:
+	Actor();
 	Actor(const std::string& path);
-	void tick(float deltaTime);
-	void draw(Shader& shader);
+	virtual ~Actor() = default;
+	virtual void logicalTick(float deltaTime);
+	virtual void rendererTick(float deltaTime);
+	virtual void draw(Shader& shader);
 
 	void setPosition(const glm::vec3& position);
 	void setScale(const glm::vec3& scale);
 	void setRotaion(const glm::quat& rotation);
+
+	glm::vec3 getPosition();
+	glm::vec3 getScale();
+	glm::quat getRotation();
+
 	std::pair<glm::vec3, glm::vec3> getAABB();
+
+protected:
+	GladGLContext* gl;
+	Model model;
+	std::unique_ptr<Animation> animation;
+	Animator animator;
+
 private:
 	void updateTransform();
 
-	GladGLContext* gl;
-	Model model;
-	Animation danceAnimation;
-	Animator animator;
 	glm::vec3 position = glm::vec3(0);
 	glm::vec3 scale = glm::vec3(1);
 	glm::quat rotation = glm::quat(1, 0, 0, 0);
diff --git a/ToyEngine/src/Animation.h b/ToyEngine/src/Animation.h
index 54c6908..9297261 100644
--- a/ToyEngine/src/Animation.h
+++ b/ToyEngine/src/Animation.h
@@ -7,6 +7,7 @@
 #include "Bone.h"
 #include "Model.h"
 #include <functional>
+#include <set>
 
 struct AssimpNodeData
 {
@@ -41,16 +42,16 @@ public:
 	{
 	}
 
+	bool available()
+	{
+		return m_TicksPerSecond;
+	}
+
 	Bone* FindBone(const std::string& name)
 	{
-		auto iter = std::find_if(m_Bones.begin(), m_Bones.end(),
-			[&](const Bone& Bone)
-			{
-				return Bone.GetBoneName() == name;
-			}
-		);
+		auto iter = m_Bones.find(name);
 		if (iter == m_Bones.end()) return nullptr;
-		else return &(*iter);
+		else return &iter->second;
 	}
 
 
@@ -81,7 +82,8 @@ private:
 				boneInfoMap[boneName].id = boneCount;
 				boneCount++;
 			}
-			m_Bones.push_back(Bone(channel->mNodeName.data,
+
+			m_Bones.emplace(std::piecewise_construct, std::forward_as_tuple(channel->mNodeName.data), std::forward_as_tuple(channel->mNodeName.data,
 				boneInfoMap[channel->mNodeName.data].id, channel));
 		}
 
@@ -103,9 +105,11 @@ private:
 			dest.children.push_back(newData);
 		}
 	}
-	float m_Duration;
-	int m_TicksPerSecond;
-	std::vector<Bone> m_Bones;
+	float m_Duration = 0.f;
+	int m_TicksPerSecond = 0;
+	std::unordered_map<std::string, Bone> m_Bones;
+
+	//std::set<Bone> m_Bones;
 	AssimpNodeData m_RootNode;
 	std::map<std::string, BoneInfo> m_BoneInfoMap;
 };
diff --git a/ToyEngine/src/Animator.h b/ToyEngine/src/Animator.h
index 9fb595d..0122aab 100644
--- a/ToyEngine/src/Animator.h
+++ b/ToyEngine/src/Animator.h
@@ -11,37 +11,43 @@ class Animator
 public:
 	static constexpr GLint kMaxBone = 100;
 
-	Animator(GladGLContext* gl, Animation* animation) : gl(gl)
+	Animator(GladGLContext* gl, Animation* animation)
+		: gl(gl)
 	{
-		currentTime = 0.0;
-		currentAnimation = animation;
-
-		finalBoneMatrices.reserve(100);
-
-		for (int i = 0; i < 100; i++)
-			finalBoneMatrices.push_back(glm::mat4(1.0f));
-
-		gl->CreateBuffers(1, &finalBonesMatricesUBO);
-		gl->NamedBufferData(finalBonesMatricesUBO, sizeof(glm::mat4) * Animator::kMaxBone, nullptr, GL_DYNAMIC_DRAW);
+		playAnimation(animation);
 	}
 
-	void UpdateAnimation(float deltaTime)
+	void updateAnimation(float deltaTime)
 	{
 		if (currentAnimation)
 		{
 			currentTime += currentAnimation->GetTicksPerSecond() * deltaTime;
 			currentTime = fmod(currentTime, currentAnimation->GetDuration());
-			CalculateBoneTransform(&currentAnimation->GetRootNode(), glm::mat4(1.0f));
+			calculateBoneTransform(&currentAnimation->GetRootNode(), glm::mat4(1.0f));
 		}
 	}
 
-	void PlayAnimation(Animation* pAnimation)
+	void playAnimation(Animation* pAnimation)
 	{
 		currentAnimation = pAnimation;
 		currentTime = 0.0f;
+
+		if (currentAnimation)
+		{
+			finalBoneMatrices.clear();
+			finalBoneMatrices.reserve(kMaxBone);
+			for (int i = 0; i < kMaxBone; i++)
+				finalBoneMatrices.push_back(glm::mat4(1.0f));
+
+			if (!finalBonesMatricesUBO)
+			{
+				gl->CreateBuffers(1, &finalBonesMatricesUBO);
+				gl->NamedBufferData(finalBonesMatricesUBO, sizeof(glm::mat4) * Animator::kMaxBone, nullptr, GL_DYNAMIC_DRAW);
+			}
+		}
 	}
 
-	void CalculateBoneTransform(const AssimpNodeData* node, glm::mat4 parentTransform)
+	void calculateBoneTransform(const AssimpNodeData* node, glm::mat4 parentTransform)
 	{
 		std::string nodeName = node->name;
 		glm::mat4 nodeTransform = node->transformation;
@@ -56,33 +62,33 @@ public:
 
 		glm::mat4 globalTransformation = parentTransform * nodeTransform;
 
-		auto boneInfoMap = currentAnimation->GetBoneIDMap();
-		if (boneInfoMap.find(nodeName) != boneInfoMap.end())
+		auto& boneInfoMap = currentAnimation->GetBoneIDMap();
+		if (auto iter = boneInfoMap.find(nodeName); iter != boneInfoMap.end())
 		{
-			int index = boneInfoMap[nodeName].id;
-			glm::mat4 offset = boneInfoMap[nodeName].offset;
+			auto& [index, offset] = iter->second;
 			finalBoneMatrices[index] = globalTransformation * offset;
 		}
 
 		for (int i = 0; i < node->childrenCount; i++)
-			CalculateBoneTransform(&node->children[i], globalTransformation);
+			calculateBoneTransform(&node->children[i], globalTransformation);
 	}
 
-	std::vector<glm::mat4> GetFinalBoneMatrices()
+	std::vector<glm::mat4> getFinalBoneMatrices()
 	{
 		return finalBoneMatrices;
 	}
 
 	GLuint getFinalBonesMatricesUBO()
 	{
-		gl->NamedBufferSubData(finalBonesMatricesUBO, 0, finalBoneMatrices.size() * sizeof(finalBoneMatrices[0]), finalBoneMatrices.data());
+		if (finalBonesMatricesUBO)
+			gl->NamedBufferSubData(finalBonesMatricesUBO, 0, finalBoneMatrices.size() * sizeof(finalBoneMatrices[0]), finalBoneMatrices.data());
 		return finalBonesMatricesUBO;
 	}
 
 private:
 	GladGLContext* gl;
 	std::vector<glm::mat4> finalBoneMatrices;
-	GLuint finalBonesMatricesUBO;
-	Animation* currentAnimation;
+	GLuint finalBonesMatricesUBO = 0;
+	Animation* currentAnimation = nullptr;
 	float currentTime;
 };
diff --git a/ToyEngine/src/Bone.h b/ToyEngine/src/Bone.h
index 64edaf6..8dac95d 100644
--- a/ToyEngine/src/Bone.h
+++ b/ToyEngine/src/Bone.h
@@ -114,6 +114,10 @@ public:
 		assert(0);
 	}
 
+	bool operator<(const Bone& e) const
+	{
+		return m_ID < e.m_ID;
+	}
 
 private:
 
diff --git a/ToyEngine/src/DemoWorld.cpp b/ToyEngine/src/DemoWorld.cpp
new file mode 100644
index 0000000..d473d01
--- /dev/null
+++ b/ToyEngine/src/DemoWorld.cpp
@@ -0,0 +1,33 @@
+#include "DemoWorld.h"
+#include "Particle.h"
+
+DemoWorld::DemoWorld()
+{
+	std::string modelFilePath;
+	//modelFilePath = "E:\\3D Objects\\plane\\obj\\plane.obj";
+	//modelFilePath = "E:\\3D Objects\\plane\\plane.gltf";
+	modelFilePath = "Models/vampire/vampire.gltf";
+	//modelFilePath = "E:\\3D Objects\\cup\\cup.gltf";
+	//modelFilePath = "E:\\3D Objects\\Sponza\\Sponza.gltf";
+
+	auto actor = std::make_shared<Actor>(modelFilePath);
+	actor->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
+	auto actor2 = std::make_shared<Actor>(modelFilePath);
+	actor2->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
+	actor2->setPosition({ 1,0,-1 });
+	auto actor3 = std::make_shared<Actor>(modelFilePath);
+	actor3->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
+	actor3->setPosition({ -1,0,-1 });
+	auto sponza = std::make_shared<Actor>("Models\\Sponza\\Sponza.gltf");
+	sponza->setScale(glm::vec3(2));
+
+	auto particle = std::make_shared<Particle>(10);
+	particle->setPosition({ 4, 5, 0 });
+	particle->addForce(glm::vec3(0, -particle->getMass() * 9.8f, 0));
+
+	addActor(actor);
+	addActor(actor2);
+	addActor(actor3);
+	addActor(sponza);
+	addActor(particle);
+}
diff --git a/ToyEngine/src/DemoWorld.h b/ToyEngine/src/DemoWorld.h
new file mode 100644
index 0000000..896fc19
--- /dev/null
+++ b/ToyEngine/src/DemoWorld.h
@@ -0,0 +1,9 @@
+#pragma once
+#include "World.h"
+
+class DemoWorld : public World
+{
+public:
+	DemoWorld();
+};
+
diff --git a/ToyEngine/src/MainWindow.cpp b/ToyEngine/src/MainWindow.cpp
index 1723c3f..263a29f 100644
--- a/ToyEngine/src/MainWindow.cpp
+++ b/ToyEngine/src/MainWindow.cpp
@@ -2,6 +2,8 @@
 #include "IblUtils.h"
 #include "RenderPass.h"
 #include "World.h"
+#include "Particle.h"
+#include "DemoWorld.h"
 
 MainWindow::MainWindow()
 	: camera(glm::vec3(0.0f, 0.0f, 3.0f))
@@ -50,39 +52,18 @@ int MainWindow::exec()
 	gl->DepthFunc(GL_LEQUAL);
 	gl->Enable(GL_TEXTURE_CUBE_MAP_SEAMLESS);
 
-	std::string modelFilePath;
-	//modelFilePath = "E:\\3D Objects\\plane\\obj\\plane.obj";
-	//modelFilePath = "E:\\3D Objects\\plane\\plane.gltf";
-	modelFilePath = "Models/vampire/vampire.gltf";
-	//modelFilePath = "E:\\3D Objects\\cup\\cup.gltf";
-	//modelFilePath = "E:\\3D Objects\\Sponza\\Sponza.gltf";
+	std::unique_ptr<World> world = std::make_unique<DemoWorld>();
 
-	auto actor = std::make_shared<Actor>(modelFilePath);
-	actor->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
-	auto actor2 = std::make_shared<Actor>(modelFilePath);
-	actor2->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
-	actor2->setPosition({ 1,0,-1 });
-	auto actor3 = std::make_shared<Actor>(modelFilePath);
-	actor3->setRotaion(glm::angleAxis(glm::radians(-90.f), glm::vec3(1, 0, 0)));
-	actor3->setPosition({ -1,0,-1 });
-	auto sponza = std::make_shared<Actor>("Models\\Sponza\\Sponza.gltf");
-	sponza->setScale(glm::vec3(2));
-	World world;
-	world.addActor(actor);
-	world.addActor(actor2);
-	world.addActor(actor3);
-	world.addActor(sponza);
-
-	auto [minPos, maxPos] = world.getAABB();
+	auto [minPos, maxPos] = world->getAABB();
 	std::cout << std::format("{},{},{} {},{},{}\n", minPos.x, minPos.y, minPos.z, maxPos.x, maxPos.y, maxPos.z);
 
-	light.sceneAABB = world.getAABB();
+	light.sceneAABB = world->getAABB();
 
 	glm::mat4 projection, view;
 	auto [skyCubemap, irradianceMap, prefilterMap, brdfLUTTexture] = IblUtils::precomputeCubemaps(gl.get());
 
-	ShadowMapPass shadowMapPass(gl.get(), shadowFboHandle, shadowMapResolution, world, light);
-	GeometryPass geometryPass(gl.get(), frameWidth, frameHeight, fbo, world, projection, view);
+	ShadowMapPass shadowMapPass(gl.get(), shadowFboHandle, shadowMapResolution, *world, light);
+	GeometryPass geometryPass(gl.get(), frameWidth, frameHeight, fbo, *world, projection, view);
 	LightingPass lightingPass(gl.get(), frameWidth, frameHeight, view, camera, light, mainLightRadiance,
 		gbuffers, shadowGbuffer, irradianceMap, prefilterMap, brdfLUTTexture);
 	FinalPass finalPass(gl.get(), frameWidth, frameHeight, gbuffers, exposure);
@@ -92,14 +73,35 @@ int MainWindow::exec()
 	glfwGetFramebufferSize(window, &w, &h);
 	framebufferSizeCallback(window, w, h);
 
+	int logicalTickCount = 0;
+	auto logicalThread = std::jthread([&](std::stop_token stop) {
+		using namespace std::chrono_literals;
+		constexpr auto targetDuration = 1666us;
+		auto sleepTime = 0ns;
+		auto lastTick = std::chrono::high_resolution_clock::now();
+		while (!stop.stop_requested())
+		{
+			auto currentTick = std::chrono::high_resolution_clock::now();
+			auto deltaTime = currentTick - lastTick;
+			double deltaTime_s = std::chrono::duration<double>(deltaTime).count();
+			lastTick = currentTick;
+			processInput(window, deltaTime_s);
+			world->logicalTick(deltaTime_s);
+			logicalTickCount++;
+
+			sleepTime = targetDuration - (deltaTime - sleepTime);
+			std::this_thread::sleep_for(sleepTime);
+		}
+		});
+
+	float lastFrame = glfwGetTime();
 	while (!glfwWindowShouldClose(window))
 	{
 		float currentFrame = glfwGetTime();
-		deltaTime = currentFrame - lastFrame;
+		float deltaTime = currentFrame - lastFrame;
 		lastFrame = currentFrame;
-		processInput(window);
 
-		world.tick(deltaTime);
+		world->rendererTick(deltaTime);
 
 		projection = camera.getProjectionMatrix();
 		view = camera.getViewMatrix();
@@ -112,11 +114,24 @@ int MainWindow::exec()
 
 		glfwSwapBuffers(window);
 		glfwPollEvents();
+
+		static float accTime = 0, frameCnt = 0;
+		accTime += deltaTime;
+		frameCnt++;
+		if (accTime > 1.)
+		{
+			std::cout << std::format("{:20}\r", "");
+			std::cout << std::format("FPS: {:.2f} TPS: {:.2f}\r", frameCnt / accTime, logicalTickCount / accTime);
+			accTime = 0;
+			frameCnt = 0;
+			logicalTickCount = 0;
+		}
 	}
 
 	glfwTerminate();
 }
-void MainWindow::processInput(GLFWwindow* window)
+
+void MainWindow::processInput(GLFWwindow* window, float deltaTime)
 {
 	if (glfwGetKey(window, GLFW_KEY_ESCAPE) == GLFW_PRESS)
 		glfwSetWindowShouldClose(window, true);
diff --git a/ToyEngine/src/MainWindow.h b/ToyEngine/src/MainWindow.h
index 7f52f9e..c21422e 100644
--- a/ToyEngine/src/MainWindow.h
+++ b/ToyEngine/src/MainWindow.h
@@ -18,7 +18,7 @@ private:
 	void framebufferSizeCallback(GLFWwindow* window, int width, int height);
 	void mouseCallback(GLFWwindow* window, double xpos, double ypos);
 	void scrollCallback(GLFWwindow* window, double xoffset, double yoffset);
-	void processInput(GLFWwindow* window);
+	void processInput(GLFWwindow* window, float deltaTime);
 
 	static constexpr int kWindowWidth = 1200;
 	static constexpr int kWindowHeight = 675;
@@ -27,11 +27,8 @@ private:
 
 	Camera camera;
 	Light light;
-	glm::vec3 mainLightRadiance = 40.f * glm::normalize(glm::vec3(0.7529, 0.7450, 0.6784));
-	float exposure = 1;
-
-	float deltaTime = 0.0f;
-	float lastFrame = 0.0f;
+	glm::vec3 mainLightRadiance = 30.f * glm::normalize(glm::vec3(0.7529, 0.7450, 0.6784));
+	float exposure = 0.6f;
 
 	std::unique_ptr<GladGLContext> gl;
 
diff --git a/ToyEngine/src/Mesh.cpp b/ToyEngine/src/Mesh.cpp
index 5d4b094..8fdadf6 100644
--- a/ToyEngine/src/Mesh.cpp
+++ b/ToyEngine/src/Mesh.cpp
@@ -1,9 +1,9 @@
 #include "Mesh.h"
 
-Vertex::Vertex(const aiVector3D& position, const aiVector3D& normal, const aiVector3D& texCoords)
-	: position(position.x, position.y, position.z)
-	, normal(normal.x, normal.y, normal.z)
-	, texCoords(texCoords.x, texCoords.y)
+Vertex::Vertex(const glm::vec3& position, const glm::vec3& normal, const glm::vec2& texCoords)
+	: position(position)
+	, normal(normal)
+	, texCoords(texCoords)
 {
 	for (std::size_t i = 0; i < kMaxBoneInfluence; i++)
 	{
@@ -12,6 +12,11 @@ Vertex::Vertex(const aiVector3D& position, const aiVector3D& normal, const aiVec
 	}
 }
 
+Vertex::Vertex(const aiVector3D& position, const aiVector3D& normal, const aiVector3D& texCoords)
+	: Vertex({position.x, position.y, position.z}, {normal.x, normal.y, normal.z}, {texCoords.x, texCoords.y})
+{
+}
+
 void Vertex::setBoneData(int boneID, float weight)
 {
 	if (weight == 0) return;
@@ -43,29 +48,12 @@ void Mesh::draw(Shader& shader)
 	shader.setUniformValue("baseColor", baseColor);
 	shader.setUniformValue("metallicRoughness", metallicRoughness);
 	gl->BindVertexArray(VAO);
-	gl->DrawElements(GL_TRIANGLES, indices.size(), GL_UNSIGNED_INT, 0);
+	gl->DrawElements(drawMode, indices.size(), GL_UNSIGNED_INT, 0);
 	gl->BindVertexArray(0);
 }
 
 void Mesh::setupMesh()
 {
-	//for (auto& v : vertices)
-	//{
-	//	if (v.boneIDs[0] == 6 && v.boneIDs[1] == 14 && v.boneIDs[2] == 18 && v.boneIDs[3] == 22)
-	//	{
-	//		v.boneIDs[0] = -1;
-	//		v.boneIDs[1] = -1;
-	//		v.boneIDs[2] = -1;
-	//		v.boneIDs[3] = -1;
-	//	}
-	//	for (int i = 0; i < kMaxBoneInfluence; i++)
-	//	{
-	//		std::cout << v.boneIDs[i] << " ";
-	//	}
-	//	std::cout << std::endl;
-	//}
-
-
 	gl->GenVertexArrays(1, &VAO);
 	gl->GenBuffers(1, &VBO);
 	gl->GenBuffers(1, &EBO);
@@ -76,7 +64,6 @@ void Mesh::setupMesh()
 	gl->BindBuffer(GL_ELEMENT_ARRAY_BUFFER, EBO);
 	gl->BufferData(GL_ELEMENT_ARRAY_BUFFER, indices.size() * sizeof(unsigned int), &indices[0], GL_STATIC_DRAW);
 
-
 	enum VertexAttribute : GLuint {
 		kPosition = 0, kNormal = 1, kTexCoords = 2, kBoneIDs = 3, kBoneWeights = 4
 	};
diff --git a/ToyEngine/src/Mesh.h b/ToyEngine/src/Mesh.h
index ae8f9a1..14c9950 100644
--- a/ToyEngine/src/Mesh.h
+++ b/ToyEngine/src/Mesh.h
@@ -16,6 +16,7 @@ struct Vertex {
 	int boneIDs[kMaxBoneInfluence];
 	float boneWeights[kMaxBoneInfluence];
 
+	Vertex(const glm::vec3& position, const glm::vec3& normal, const glm::vec2& texCoords);
 	Vertex(const aiVector3D& position, const aiVector3D& normal, const aiVector3D& texCoords);
 	void setBoneData(int boneID, float weight);
 };
@@ -25,6 +26,7 @@ public:
 	glm::mat4 model;
 	std::vector<Vertex> vertices;
 	std::vector<unsigned int> indices;
+	GLenum drawMode = GL_TRIANGLES;
 	GLuint textureBasecolor = 0;
 	GLuint textureMetallicRoughness = 0;
 	GLuint textureNormal = 0;
@@ -32,12 +34,10 @@ public:
 	glm::vec2 metallicRoughness;
 	unsigned int VAO;
 
-	Mesh(GladGLContext* gl, const std::vector<Vertex>& vertices, const std::vector<unsigned int>& indices, const glm::mat4& model);
+	Mesh(GladGLContext* gl, const std::vector<Vertex>& vertices, const std::vector<unsigned int>& indices, const glm::mat4& model = glm::mat4(1));
 	void draw(Shader& shader);
 	void setupMesh();
 private:
 	GladGLContext* gl;
 	unsigned int VBO, EBO;
-
-	
 };
\ No newline at end of file
diff --git a/ToyEngine/src/Model.cpp b/ToyEngine/src/Model.cpp
index d420e73..2e4b475 100644
--- a/ToyEngine/src/Model.cpp
+++ b/ToyEngine/src/Model.cpp
@@ -1,13 +1,76 @@
 #include "Model.h"
 #include <glm/gtc/type_ptr.hpp>
 #include <glm/gtc/matrix_transform.hpp>
+#include <glm/ext/scalar_constants.hpp>
 #include <fstream>
 #include <sstream>
 #include <iostream>
 #include <stb_image.h>
 
-Model::Model(GladGLContext* gl, std::string const& path)
+Model Model::createSphere(GladGLContext* gl, const glm::vec3& baseColor, const glm::vec2& metallicRoughness)
+{
+	Model sphere(gl);
+
+	std::vector<Vertex> vertices;
+	std::vector<unsigned int> indices;
+
+	constexpr unsigned int kXSegments = 64;
+	constexpr unsigned int kYSegments = 64;
+
+	for (unsigned int x = 0; x <= kXSegments; ++x)
+	{
+		for (unsigned int y = 0; y <= kYSegments; ++y)
+		{
+			float xSegment = (float)x / (float)kXSegments;
+			float ySegment = (float)y / (float)kYSegments;
+
+			constexpr auto PI = glm::pi<float>();
+			float xPos = std::cos(xSegment * 2.0f * PI) * std::sin(ySegment * PI);
+			float yPos = std::cos(ySegment * PI);
+			float zPos = std::sin(xSegment * 2.0f * PI) * std::sin(ySegment * PI);
+
+			vertices.emplace_back(glm::vec3(xPos, yPos, zPos), glm::vec3(xPos, yPos, zPos), glm::vec2(xSegment, ySegment));
+		}
+	}
+
+	bool oddRow = false;
+	for (unsigned int y = 0; y < kYSegments; ++y)
+	{
+		if (!oddRow) // even rows: y == 0, y == 2; and so on
+		{
+			for (unsigned int x = 0; x <= kXSegments; ++x)
+			{
+				indices.push_back(y * (kXSegments + 1) + x);
+				indices.push_back((y + 1) * (kXSegments + 1) + x);
+			}
+		}
+		else
+		{
+			for (int x = kXSegments; x >= 0; --x)
+			{
+				indices.push_back((y + 1) * (kXSegments + 1) + x);
+				indices.push_back(y * (kXSegments + 1) + x);
+			}
+		}
+		oddRow = !oddRow;
+	}
+
+	auto mesh = std::make_unique<Mesh>(gl, vertices, indices);
+	mesh->drawMode = GL_TRIANGLE_STRIP;
+	mesh->baseColor = baseColor;
+	mesh->metallicRoughness = metallicRoughness;
+	sphere.meshes.emplace_back(std::move(mesh));
+
+	return sphere;
+}
+
+Model::Model(GladGLContext* gl)
 	: gl(gl)
+{
+}
+
+Model::Model(GladGLContext* gl, std::string const& path)
+	: Model(gl)
 {
 	loadModel(path);
 }
diff --git a/ToyEngine/src/Model.h b/ToyEngine/src/Model.h
index 8dc91a8..4f8c07f 100644
--- a/ToyEngine/src/Model.h
+++ b/ToyEngine/src/Model.h
@@ -26,6 +26,8 @@ public:
 	std::map<std::string, BoneInfo> boneInfoMap;
 	int boneCount = 0;
 
+	static Model createSphere(GladGLContext* gl, const glm::vec3& baseColor = glm::vec3(0.5, 0, 0), const glm::vec2& metallicRoughness = glm::vec2(0, 0.5));
+	Model(GladGLContext* gl);
 	Model(GladGLContext* gl, std::string const& path);
 	void draw(Shader& shader);
 	void setTransform(const glm::mat4& trans);
diff --git a/ToyEngine/src/Particle.cpp b/ToyEngine/src/Particle.cpp
new file mode 100644
index 0000000..4584769
--- /dev/null
+++ b/ToyEngine/src/Particle.cpp
@@ -0,0 +1,31 @@
+#include "Particle.h"
+
+Particle::Particle(float mass)
+	: Actor()
+	, mass(mass)
+{
+	model = Model::createSphere(gl);
+	setScale(glm::vec3(0.5));
+}
+
+void Particle::logicalTick(float deltaTime)
+{
+	auto pos = getPosition() + speed * deltaTime + 0.5f * resultantForce / mass * deltaTime * deltaTime;
+	speed += resultantForce / mass * deltaTime;
+	if (speed.y < 0 && pos.y < 0.5)
+	{
+		speed.y = -speed.y;
+	}
+	setPosition(pos);
+}
+
+void Particle::addForce(glm::vec3 force)
+{
+	forces.push_back(force);
+	resultantForce += force;
+}
+
+float Particle::getMass()
+{
+	return mass;
+}
diff --git a/ToyEngine/src/Particle.h b/ToyEngine/src/Particle.h
new file mode 100644
index 0000000..1dee2a3
--- /dev/null
+++ b/ToyEngine/src/Particle.h
@@ -0,0 +1,18 @@
+#pragma once
+#include "Actor.h"
+
+class Particle : public Actor
+{
+public:
+	Particle(float mass);
+	virtual ~Particle() = default;
+	virtual void logicalTick(float deltaTime);
+	void addForce(glm::vec3 force);
+	float getMass();
+private:
+	float mass;
+	glm::vec3 speed = glm::vec3(0.f);
+	std::vector<glm::vec3> forces;
+	glm::vec3 resultantForce = glm::vec3(0);
+};
+
diff --git a/ToyEngine/src/RenderPass.cpp b/ToyEngine/src/RenderPass.cpp
index 4d17a73..8d929ab 100644
--- a/ToyEngine/src/RenderPass.cpp
+++ b/ToyEngine/src/RenderPass.cpp
@@ -73,7 +73,7 @@ void GeometryPass::dispatch()
 				glm::mat4 trans = glm::mat4(1.0f);
 				trans = glm::translate(trans, glm::vec3(
 					(float)(col - (nrColumns / 2)) * spacing,
-					(float)(row - (nrRows / 2)) * spacing,
+					(float)(row - (nrRows / 2)) * spacing + 5,
 					-2.0f
 				));
 				plainShader.setUniformValue("model", trans);
diff --git a/ToyEngine/src/World.cpp b/ToyEngine/src/World.cpp
index 72284f3..96b74a7 100644
--- a/ToyEngine/src/World.cpp
+++ b/ToyEngine/src/World.cpp
@@ -1,9 +1,15 @@
 #include "World.h"
 
-void World::tick(float deltaTime)
+void World::logicalTick(float deltaTime)
 {
 	for (auto& actor : actors)
-		actor->tick(deltaTime);
+		actor->logicalTick(deltaTime);
+}
+
+void World::rendererTick(float deltaTime)
+{
+	for (auto& actor : actors)
+		actor->rendererTick(deltaTime);
 }
 
 void World::draw(Shader& shader)
@@ -28,4 +34,4 @@ std::pair<glm::vec3, glm::vec3> World::getAABB()
 		maxPos = glm::max(maxPos, max);
 	}
 	return { minPos, maxPos };
-}
+}
\ No newline at end of file
diff --git a/ToyEngine/src/World.h b/ToyEngine/src/World.h
index 4dd841e..10b6e26 100644
--- a/ToyEngine/src/World.h
+++ b/ToyEngine/src/World.h
@@ -5,7 +5,8 @@ class World
 {
 public:
 	std::vector<std::shared_ptr<Actor>> actors;
-	void tick(float deltaTime);
+	virtual void logicalTick(float deltaTime);
+	virtual void rendererTick(float deltaTime);
 	void draw(Shader& shader);
 	void addActor(std::shared_ptr<Actor> actor);
 	std::pair<glm::vec3, glm::vec3> getAABB();