The “Footsteps” motion in the motion camera doesn’t work when using Physical render.

I have no clue why it doesn’t work, as far as I know, physical render only affects visual stuff such as depth of field, motion blur, etc.

For now, I’m just using a vibrate tag when the camera is walking but it’s not ideal. Please tell me if you know how to fix this.

I would like to make the grey cube always appear in the front, even if the white cube is in front of it. I know this is possible in blender, but I can’t figure out how to do it in C4D.