Here's how to translate objects in P3D:
size(200, 200, P3D); //Starting P3D renderer
fill(255, 0, 0, 150); //transparent red
rect(10, 10, 100, 100); //first rectangle
fill(0, 0, 255, 150); //transparent blue
translate(50, 50, 50); //translate x, y and z by 50 pixels
rect(0, 0, 100, 100); //sec...