Platinum Arts Sandbox - Free 3D Game Maker Forum

After i make a 3D model, do i only have to export it and put it in a map, or do i first have to do something or what?

you need to convert it to a filetype that sandbox supports (obj md2 md3 or md5) and put it into sandbox models folder. You also need to make a cfg file for your model. Check the wiki for more info