To define how a spawned object moves or interacts in your 3D scenes, you set it up as a physics actor. For example, to add collision to an object, you configure the mesh by adding a physics actor using the Unit Editor.

Refer also to Basic physics concepts for more detailed information on worlds, actors, and shapes.

1. In the Asset Browser, navigate to select the unit.

2. Double-click the unit to launch the Unit Editor.

3. In the Unit Editor tree view, right-click the asset and select Create Physics Actor from the pop-up menu.

   Tip: Ctrl+click to select multiple objects, then right-click and select Create Physics Actors.

4. Select the newly created actor in the tree view.

   The actor properties display in the properties panel on the right in the Unit Editor.

5. In the properties panel, set the following:
   • Actor Template: Set this mode to determine whether the actor moves (Dynamic) or never moves (Static) and collides with other actors. For example, you might set a ball actor to Dynamic, and the floor plane to Static so that the ball doesn't simply fall forever in the physics world.
   • For dynamic actors, set the Mass value to represent the weight of the object. (For example, 0.08Kg for the weight of a pinball.)
   • Ensure that Enabled is on.
   • Under the Shape heading, select a Type that approximately matches the shape of your object. For example, select Sphere for a ball, or Capsule for a bone. Note that the Mesh type is not supported for Dynamic actors.

6. Close the Unit Editor window and click Save when prompted.

Note: When you scale physics enabled units, the physics actors and the constraints get scaled accordingly to the scale. While a uniform scaling (1,1,1) of physics objects is preferred both in your DCC tool and in 3ds Max Interactive, you can also apply a non-uniform scale. If the imported unit has a single actor, set the scale on the physics actor. For a unit with several physics actors, you can apply the scale to the unit if all the actors have the same orientation. If the physics actors have a different orientation than the unit or in other cases, you must scale the unit in the DCC tool or modify its node hierarchy in the DCC for all the physics actors to have the same orientation.

Note: During migration, physics are lost when units are re-imported. To fix this issue, delete the .physics file associated with the unit, then right-click the unit in the Asset Browser and select Enable Static Physics.