I have a 3d model i'm trying to combine with another, but i can't get it to work correctly. The material is 1.5 thick, the 3d model has a thickness of 1, so model is at the top of the material, with a .5 base. Then i create a simple 3d model of a square i want attached under it. The square section i only want to be 1 inch thick.. No matter how i try to combine them, the model height i set for the square part, affects the height of the first 3d model. I must be missing something. How can i add the second part without changing the other?