It would be great to have an either self hosted or embeddable interactive 3D model viewer that can show STL or STEP files (typical CAD formats).
Requirements:
* easy import/export from 3D CAD software into the viewer
* proper light setup and implemented self shadowing of models, otherwise its really hard to see the 3D nature of a part
* WebGL, to prevent dependency on uncommon plugins on user side (flash, unity3d, etc.) - should be as widely supported out of the box as possible