CNC cut tail light housing with attachment tabs should match the shape of the trailer. I formed this by hand basically. It's 0.03" aluminum, so I could tweak it until it fit right. I had predrilled holes on the cnc machine to match the lights so that helped a bit. I attached the light, then kept pressing until the metal matched the light. Drawing this took some time. None of this was modeled in 3d. So brute force was used to make this flat pattern.