Character Animator Physics... How to move the ground

When I enable physics for a scene, the physics-enabled objects fall to the bottom of the screen.  This does not work for a scene with perspective.  I want the objects to fall to the level where the puppets are standing in the scene.  I thought about adding static layers with "collide" to the points where the puppets would be standing but I want to know if there is a better way.  Thanks in advance.