You can use collision layers to organize collisions between multiple objects that share the same Maya Nucleus solver. With the Collision Layer attribute in the nClothShape, nParticleShape , and hairSystemShape Attribute Editor tab, you can specify in which collision layer an nCloth or nParticle object resides. nCloth and nParticle objects on the same collision layer collide normally. However, when Nucleus objects are on different layers, the objects on lower value layers will have priority over objects on higher value layers.
For example, an nCloth object on collision layer 0.0 will push an nCloth object on collision layer 1.0, which in turn will push the nCloth object on collision layer 2.0. This collision priority occurs in the range set by the Collision Layer Range attribute in the nucleus Attribute Editor tab.
You can set the Collision Layer Range to specify how close two Nucleus objects must be in order for them to collide. If the differential between the Collision Layer values for the two objects is less than the Collision Layer Range, the objects can collide. For example, if object A has a Collision Layer value of 2 and object B has a Collision Layer value of 5, then the differential between their Collision Layer values is 3. Therefore, they can only collide when the Collision Layer Range value is less than 3.
For more information on using collision layers, see Setting collision layers.
Nucleus objects only collide with other Nucleus objects that are in the same collision layer, or in layers of higher value.