Rigging & animation · Intermediate

Physics simulation

Letting the software work out motion from gravity, forces and collisions

Also called Dynamics

What is physics simulation in 3D?

Physics simulation is letting the software calculate motion from forces like gravity, collisions and wind, instead of animating it by hand. You give objects properties such as mass and bounciness, press play, and the computer works out how they fall, crash and settle.

Think of it like this

Like setting up dominoes: you arrange the pieces and nudge the first one, and physics decides everything that happens after.

Where it fits in a 3D project

  1. Create
  2. Surface
  3. Rig
  4. Animate
  5. Render
  6. Export

Animate: Making things move over time.

How physics simulation works

  1. 01Mark objects as active, which move, or passive, which only get hit.
  2. 02Set properties such as mass, friction and bounciness.
  3. 03Add forces like gravity or wind, then play the timeline.
  4. 04Bake the result so it plays back the same way every time.

Physics simulation vs keyframe animation

PropertyPhysics simulationKeyframe animation
Motion comes fromForces the computer calculatesPoses you set by hand
ControlIndirect, through settingsTotal
Best forCrashes, debris, piles and clothCharacters and performances

Simulate chaotic motion with many pieces, and keyframe anything that needs a performance or exact timing; many shots mix both.

Where physics simulation is used

  • Objects falling, colliding and tumbling
  • Breaking glass, crumbling walls and flying debris
  • Wobble on soft things like jelly or cushions

Beginner tip

Model at real-world scale. Simulations assume meters and real gravity, so a cup modeled ten meters tall falls in slow motion and looks wrong.

Terms related to physics simulation

Physics simulation FAQ

Rigid body vs soft body: what is the difference?
A rigid body keeps its shape, like a brick or a bowling ball, and only moves and spins. A soft body squashes and wobbles, like jelly or a rubber ball. Rigid bodies are much faster to simulate.
What is baking a simulation?
Saving the calculated motion, to disk or as keyframes, so it plays back instantly and the same way every time. An unbaked simulation recalculates from the start whenever something changes.
Is physics simulation used in games?
Yes, in real time. Game engines run simpler physics every frame for falling objects, ragdolls and vehicles, while films run heavier simulations ahead of time and bake them.

Updated October 29, 2026 · Browse all 3D terms