The PhysX Collision operator allows you to add colliders to a PhysX simulation, and set test conditions for colliding particles.
Only mesh colliders are supported. Spacewarp colliders are not supported.
Sphere: a perfectly spherical hull.
Box: a bounding box hull.
Convex Hull: a convex hull encapsulating collider mesh vertices.
Mesh: the collider’s mesh will be used as the hull.
Restitution: the restitution coefficient for the collider. Similar to “bounce”.
Static/Dynamic friction: friction coefficients for the collider.
If a hit is found along the sweep, the implication is that the particle will collide during the next frame of the simulation. This allows you to check if a “future” collision will occur…which can help in various scenarios. For example, if you’d like to fracture geometry before it collides with an object (as opposed to after it collides), you can perform a sweep test to check for future collisions which can be used to trigger a pre-collision fracture operation.
Sweep testing ignores the angular velocity of particles and will only perform a sweep using their linear velocity. Therefore, collisions from spinning particles may be missed. Increasing the inflation parameter may help to catch those missed collisions, as the hull used to sweep the scene will be inflated by the specified value.
Inter-particle collisions: collisions between particles may satisfy the test condition.
Geometry collisions: collisions between particles and geometry colliders may satisfy the test condition.
Ground collider collisions: collisions between particles and the default PhysX ground plane may satisfy the test condition.
If any extra conditions are enabled, they will factor into whether a particle satisfies the test condition.
AND: all enabled extra conditions must be satisfied in order for a colliding particle to satisfy the test.
OR: any enabled extra conditions must be satisfied in order for a colliding particle to satisfy the test.
A particle must collide a certain number of times before it will satisfy this condition.
The minimum impulse of a particle’s collision must be above a certain value before it will satisfy this condition.
The maximum impulse of a particle’s collision must be below a certain value before it will satisfy this condition.
The penetration value of a particle’s collision must be above a certain value before it will satisfy this condition.
When greater than one, the ratio between the mass of a particle and its collider must be greater than a specified value in order to satisfy this condition. When less than one, the opposite is true. When equal to one, a particle and its collider must have the same mass in order to satisfy this condition.
When greater than one, the ratio between the volume of a particle and its colliding particle must be greater than a specified value in order to satisfy this condition. When less than one, the opposite is true. When equal to one, a particle and its colliding particle must have the same mass in order to satisfy this condition.
A particle’s event age must be within a defined range before it will satisfy this condition.
The current simulation frame must be within a defined range before particles will satisfy this condition.
Only particles with a certain PhysX collider rigidbody type will satisfy this condition.
Only particles matching a certain set of simulation groups will satisfy this condition.