points 0 links 0 torn 0 weave error 0 px stretch 0% fall drift n/a 0 fps

A position went non finite. The simulation is stopped because it can no longer be drawn. This is a guard rather than an expected outcome: position based dynamics normally stays bounded even when the integrator is wrong, which is exactly what makes a wrong integrator hard to notice.

Drape.

Cloth is a list of distances that want to be true. Grab it, cut it, tear it.

Scene

Tool

Drag to grab. 1 to 5 scenes, G/C/P tools, R resets, space pauses.

World

Gravity Wind Floor Tearable Tears past

Solver

Iterations Stiffness

Sweep order

Integrator

Frame hitches (variable dt)

Watch Fall drift, not the cloth. A free falling point is integrated alongside on the same timesteps and compared against g·t·t/2. With steady frames both integrators sit near 0.17%. Turn on hitches and the naive one walks into the tens of percent while the cloth carries on looking completely fine.

Grabbing flings

Look

Why the iteration slider changes the material. Each pass leaves (1-k) of the error, so n passes leave (1-k)ⁿ. Stiffness alone is not a property of the fabric; stiffness and iterations together are.