1. NVIDIA PhysX: 物理引擎(Physics Engine) V-lab Talk 2010/12/03 洪偉瀚

2. 大綱 甚麼是物理引擎? 物理引擎的應用 物理引擎的基本原件(PhysX) 簡單範例實作

3. 甚麼是物理引擎?

4. 甚麼是物理引擎? 物理引擎 物體位置、速度、加速度 繪圖引擎 圖像

5. 甚麼是物理引擎? • 物理計算處理器PPU(Physics Processing Unit)

6. 甚麼是物理引擎? • 鋼體動力(rigid body dynamics) • 軟體動力(soft body dynamics) • 流體動力(fluid dynamics) • 布料模擬(cloth) • 毛髮(hair) • 碰撞檢測(collision detection) • 破壞力學(destruction) • 植被(vegetation) • 粒子系統(particle system)

7. 有哪些物理引擎? http://www.havok.com/ http://www.ode.org/ http://bulletphysics.org/wordpress/ http://developer.nvidia.com/object/physx.html http://www.vxsim.com/en/simulators/

8. 物理引擎的應用 • 遊戲 • Mirror Edge (PhysX) • Crane Simulator (PhysX) • BioShock2 (Havok) • 電影&動畫 • 2012 (Bullet) • 學術 • Crane Simulation (Vortex) • Surgeon Simulation (PhysX)

9. 物理引擎的應用 • SketchUp • Blender • Unity3D • 3DsMax

10. NVIDIA PhysX • http://www.nvidia.com.tw/object/physx_new_tw.html • Developer • http://developer.nvidia.com/object/physx.html

11. 物理引擎基本原件 • 物件(Actor) • 碰撞檢測形狀(Boundary shape) • 碰撞材質(Material) • 關節(Joint)

12. Actor & Shape • An actor typically contains shapes - sometimes one, sometimes more, sometimes none. The shapes represent the physical space the actor occupies in the simulation, and are the core of collision detection. • You can create an actor with no shapes, which will then behave as a 'ghost' and collide with nothing (though it may still be jointed to other actors and affected by gravity and other applied forces or torques).However, a shapeless actor must have a body, i.e. it may not be static. Actors Shapes in actors

13. Shapes - plane • Planes (class NxPlaneShape) are useful for simple demos in which a ground plane is needed but little else. A plane is characterized in the world space plane equation with the following: ax + by + cz = d

14. Shapes - Sphere • Spheres are the simplest types of shapes. Their only property is their radius.

15. Shapes - Box • Boxes have a dimensions property. The elements of this vector are the volume's half width, half height and half depth. Specifying a large half width will yield a wide box.

16. Shapes - Capsule • Capsules, also called line swept spheres, are like cylinders that have rounded ends. Capsules are great to approximate round shapes like body parts because their collision detection is very fast and robust, even more so than boxes.

17. Rigid body properties

18. Material • When two actors collide, the collision behavior that results depends on the material properties of the actors' surfaces. For example, the surface properties determine if the actors will or will not bounce, or if they will slide or stick. Currently, the only special feature supported by materials is anisotropic friction, but other effects such as moving surfaces and more types of friction are slotted for future release.

19. Material Property • restitution • A restitution value of zero is the default which causes the joint to stop dead - a value of 1 will cause the joint to bounce back from the limit with the same velocity that it hit. • staticFriction • dynamicFriction