Collision shape and dimensions

You can change the shape and dimensions of the character physics shape at authoring time, or at runtime.

Change shape type at authoring time

To changing the character physics shape at authoring time, change the "Shape Type" in the PhysicsShape component of the character GameObject. The only limitation is that it must be a convex shape (all primitives are convex).

Changing the shape dimensions at runtime

If you want to change the character collider's dimensions at runtime, you can use the following:

CapsuleCollider* capsuleCollider = (CapsuleCollider*)physicsCollider.ColliderPtr;
CapsuleGeometry capsuleGeometry = capsuleCollider->Geometry;
capsuleGeometry.Radius = 1f;
capsuleCollider->Geometry = capsuleGeometry;

You need to make sure that the method in which you perform this has the unsafe declaration, and to write back to the PhysicsCollider component in the character update job.