3D Physics Simulation Time by Frames

3D Physics Simulation Time per Frame

Before you can render anything, a physics simulation has to bake the motion data for every frame — positions, velocities, collisions. The wall-clock time you wait for is just total = frames × seconds_per_frame. What pushes that per-frame number up is the number of rigid bodies, how many soft body iterations you run, the ragdoll constraints, and the resolution of any cloth or hair.

For a moderate scene, a Cycles cache usually lands somewhere between 1 and 30 minutes per 100 frames, and where it falls depends mostly on your solver substeps. Soft bodies and high-resolution cloth drag the most. The cheapest thing you can throw at it is a stack of rigid bodies with sleeping turned on.

Applications

You'll find this kind of sim behind destruction shots, character ragdolls, cloth, hair and fur across feature animation, games and previs. The engines doing the heavy lifting tend to be Bullet Physics (Blender, Maya), NVIDIA PhysX (Unity, Unreal), and Houdini's bullet/RBD solvers. When there's clothing involved, most studios route it through Maya nCloth or Marvelous Designer.

FAQ

What is the difference between rigid and soft body? A rigid body holds its shape and can only move or spin around. A soft body actually deforms when something pushes on it, which is what you want for jelly, muscles, inflatables and squishy props.

Can the simulation be re-cached selectively? Yes. Most DCCs will let you bake just a frame range, pin parts of the rig in place (like cloth vertices you don't want moving), and hand the cached data straight to your downstream lighting and render passes.

Why use Marvelous Designer for clothing? It works the way a real garment does — flat 2D patterns sewn together in 3D. You get believable wrinkles and drape out of that approach much sooner than you would dialing in a generic cloth solver by hand.