I need a 3D cad drawing done for a product that will be 3D printed

I'm looking to have a 3D cad drawing done of a product I want to get 3D printed. It's a 30" x 20" rectangular frame meant to sit on top of a plyometric box. As you'll see in the drawings, the internal edge must be L shaped to allow for the frame to rest on the box without falling down. The corners are to be made of a hard durable plastic material and the straight sections will be made of a rubber type material to absorb impacts.