PhysX has, in the meantime, become the primary physics engine of NVIDIA Omniverse, and for a while it was unclear if it will ever be available again for use in other applications and platforms.

PhysX是NVIDIA Omniverse的主物理引擎

We have also decided that our Flow and Blast libraries, while technically not depending on PhysX, should be part of a PhysX product family and licensed together. For that reason Flow is now bundled in the same GitHub repo and Blast will be added soon.

技术上来说，Flow和Blast并不依赖于PhysX。但是这两者还是应该属于PhysX，所以这两个库的代码会被包含在PhysX中

In terms of new features, PhysX 5 now includes former NVIDIA Flex library capabilities like finite element model based soft body dynamics, and liquid, cloth and inflatable objects using position based dynamics.

NVIDIA Flex是之前的一个库，现在PhysX 5支持了它的功能

Users completely new to PhysX should probably just start reading this user’s guide and then step through some of our very simple sample code we call snippets.

PhysX的示例工程，我们把它叫做snippets

It is important to note that PhysX does not run any code on GPUs by default. However PhysX can be configured to take advantage of CUDA capable GPUs, which provides a performance benefit proportional to the arithmetic complexity of a scene. GPU acceleration extensions are provided as an optional binary DLL. See GPU Rigid Bodies for details on how to enable GPU acceleration. Even without GPU acceleration, PhysX is fully multithreaded and SIMD-accelerated to take full advantage of modern multi-core CPUs. As mentioned above, PhysX 5 adds a number of GPU exclusive features like soft bodies. These features will not work unless the SDK is configured to run on a GPU.

PhysX的代码默认都不是运行在GPU上的。PhysX的代码可以使用GPU CUDA进行加速。GPU加速的功能作为一个单独的DLL提供。即使不使用GPU加速，在CPU上运行也是完全支持多核的。PhysX 5增加了很多GPU独占特性，这些就只能在GPU上运行了。

1. The PhysX world comprises a collection of Scenes, each containing objects called Actors;
   1. 以场景为划分单位，基本的物体叫做Actors
2. Each Scene defines its own reference frame encompassing all of space and time;
3. Actors in different Scenes do not interact with each other;
4. Characters and vehicles are complex specialized objects made from Actors;
5. Actors have physical state : position and orientation; velocity or momentum; energy; etc,
6. Actor physical state may evolve over time due to applied forces, constraints such as joints or contacts, and interactions between Actors.