I recently picked up a used BMW E46 and noticed the door panel trims were all hanging on by some duct tape. When I went to inspect, I noticed that all the clips had been broken and replaced with silicone rubber to try and hold it to the door. With some CAD and 3d Printing, I set out to replace them all and restore my door panels to their former glory.
To start off I found one of the broken clips that was still relatively together. Then I took out some callipers and measured all the important dimensions. Notably the dimension of the round metal clip (it attached to a plastic clip on the panel) and the outer dimension of the rubber part (it pushes through the actual door, and the clips lock it in place).