Performance issue. Could you help?

[mmortall]

If you don't need to get per-contact collision information, do not subscribe to OnCollision. Each contact is a fairly large struct that needs to be marshaled, whereas velocities are blittable types and won't trigger marshaling.

Simply use GetParticleVelocities during LateUpdate, that should be enough to detect if particles are asleep.

In the upcoming Obi 4.0, all solver buffers are memory mapped so there's no need to call Get/Set methods for particle properties. All values are directly accessible from the C# side of things.

Ok thanks. And GetParticleVelocities also use marshaling internally or no ?