Slides from Unite'14 where Anthony talked about physics changes available in upcoming Unity 5.0.

1. PhysX3 in Unity 5.0
Anthony Yakovlev
Unity Technologies

2. AGENDA
• Intro
• Rigidbody component overview
• Cloth overview
• WheelCollider overview
• The last slide

6. PhysX 3.3 brings us
• SDK rewrite
• Cleaner, better codebase
• New subsystems: Vehicles, Cloth
• Improved multithreading
• (Some) compatibility issues

8. Rigidbody component
• Adaptive force is disabled by default
8

9. Static,
dynamic
and
kinematic
bodies

10. Bodies
• Static & kinematic bodies
• primitive colliders
• any mesh collider
• Dynamic bodies
• primitive colliders
• CONVEX mesh colliders

11. Static bodies
• Moving static colliders is now basically free
• has been one of the most often causes of
performance issues
• static bodies are still cheaper than others

12. Triggers
• Adding trigger restricts colliders:
• primitive colliders
• convex mesh colliders
• e.g. no TerrainCollider

13. More about Rigidbody
•CCD
skeletons
are
generated
by
the
SDK
automatically
•no
64k
limitation
on
bodies
on
the
broadphase
on
desktop
targets

14. MeshCollider
• scaling mesh colliders is basically free
SCALE by Steve Swink

15. Cloth
15
• Comes in place of SkinnedCloth & InteractiveCloth
• Multithreaded
• Designed with character clothing in mind

17. Cloth
• Decoupled from the main physics update
• Needs to register colliders cloth would react on
• SphereCollider
• CapsuleCollider
• “conic capsule”
• Does not apply the forces back
17

18. WheelCollider
• Powered by the all-new PhysX Vehicles SDK
• Tyre forces now work!
• Input real world data
• New gizmo
18

20. Performance
• Core SDK is organised in tasks
• helps on multicore devices
• especially on modern desktops
• Android NEON instruction set is supported
• GPU cloth support is coming in 5.x
• PhysX3 has faster algorithms: pruners, sleeping, queries
!
• http://physxinfo.com/news/11297/the-evolution-of-physx-
sdk-performance-wise/
20

21. Performance insights
• PhysX3 is 2x faster than PhysX2 on average
• We’ve seen up to 10x performance boost for some cases
Stacks Spheres
vs.
mesh

22. Summary
• Unity 5.0 physics is 2x faster than Unity 4.x
• Multicore CPUs are now welcome
• Unity 5.0 features fixes for long standing issues
• The new WheelCollider can be used to simulate real-world
vehicles
• The new Cloth component is designed with character
clothing in mind
• PhysX3 is not 100% compatible with PhysX2, some tuning
might be required to get your old projects running
22

23. THANKS
FOR
COMING!
CATCH
ME
@
HANDS-­‐ON
LAB
AREA
Anthony
Yakovlev
anthony@unity3d.com
@AnthonyYakovlev