Dynamics

Now the rig is all connected up we can run our first simulation. A good practice when building cloth rigs is to test as you go, if we start the simulation here the shorts will simply slip down the characters body which isn’t what we want. This can be countered by increasing Friction in the nCloth objects settings but once the character is moving around it will become obvious that we need more control. This is where dynamic constraints are super useful.

The constraints on offer are very robust and you’ll be able to connect cloth in a variety of ways. The shorts will be held around the waist using a Point to Surface constraint and also use a Component to Component constraint, this essentially limits the cloth impact in that area and keeps the waist band area rigid.

The dynamic constraints work by selecting the cloth output object, shift clicking the object you want to constrain to. Certain constraints require Vertices and others require the entire Mesh. To keep our characters shorts from sliding down the body I used a Point to Surface Constraint. Select the vertices on the short_simIN_OUTPUT object then shift click the body_simIN_col object and in the nConstraint menu select Point to Surface. When creating the Component to Component constraint you’ll see that Maya creates another nRigid object for the shorts_CtA geometry. The difference here is that the rigid object has collision unchecked.

Under the hood Maya needs a rigid body for the constraints to work correctly. I prefer to make these in advance, there is a dynRigid_GRP in the rig structure for just that.