Digital Tutors: nCloth
Here are some tips for the nCloth module in Maya:
1) Make sure under modify – Evaluate nodes, the ncloth is being evaluated in order to preview it in the viewport.
2) We can use nCloth on the petals of a flower. In one of the lessons, a paint effects flower was converted to polygon (with animation), and the petals are assigned nCloth at a certain start frame in time attributes so that it falls off. Scale attribute contributes to accuracy.
3) nCloth works best with even resolution across the surface of geometry. Things like a cylinder would not be good because there is too much resolution in the center. Quads are also preferred, so use cleanup under mesh to fix triangles.
4) If we need more resolution, we should smooth the input mesh rather than the simulated one.
5) We can set keys on the solver attributes to speed things up when no collision is happening. Solver controls quality.
6) If there are more than one nCloth simulation in a scene, use collision layers to speed things up. There is also a constraint called exclude collide pairs for cloth that never meet.
7) Input mesh attraction allows us to do things like skin deforming along the jaw when punched. We might use this method to build blend shapes.
8) Similar to mesh attract, we can use rest shape to force an nCloth to take a certain shape in its simulation. The difference is that the input mesh’s position is not taken into account.
9) We could also use nCloth to deform a shape when it hits something, just like this wrench.
10) There are pressure attributes in nCloth that we can use to inflate a balloon or something!
11) Simulate tearing under the tearable surface constrain. All we need is to identify the vertices to tear.
The tutorial also contains a demo of how to tweak the cape of a character. These are the rough steps.
1) Measure the character. Divide the height that we want the character to be by the measurement. This is your space scale value.
2) Set the cape to nCloth, the character to passive.
3) To tweak our cloth, we need our character in T-pose. If it is already animated, we could set the skin cluster envelope to 0.
4) Reduce the collision thickness to better match the geometry. Tweak the friction, stretch/compression/bend resistance.
5) Use constrains (point to surface) on the neck region. Select the necessary vertices on the nCloth and the character mesh. Set the glue strength lower for a more natural effect.
6) Cache the simulation with animation on. It’s time to fix interpenetrations. One way to fix it is to duplicate the cloth mesh, fix the vertices, then set initial state to the duplicated mesh. Another attribute to look at is the push out under the shape node.
Bonus: Flying paper!
By making a plane a tearable surface and increasing it’s resolution, we could add vortex and turbulence to make a pool of flying paper! Very cool effect!