Use arrow keys to rotate, and click or press space to zoom in 1: To change the 3D model go into the "3D" sprite 2: go to costumes and select costume 1 3: and than change whatever you want in the costume to make your 3D model!
I was scrolling down the scratch page just looking at projects and saw some that were 3D, and than I found some that used cloning so I got to work and tested it out for myself