HOOPS 3D is a widely used 3D API used in interactive, visualization and engineering applications. Developer, Tech Soft 3D has developed and released a free HOOPS viewer for mobile devices.
The HOOPS mobile viewer supports native HOOPS format, HSF, as well as STL, PLY, and OBJ files. Tech Soft 3D built the 3D viewer using its own HOOPS Visualize developer toolkit.
This mobile 3D supports multi-touch gestures, let's you highlight model parts, and plays animations.