GitHub - mradugin/u3d-to-stl: Simple U3D model to STL converter based on u3d-parser from Universal 3D Sample Software https://sourceforge.net/projects/u3d/
U3D v.1.0 Unreal model conversion tool file - ModDB
What is U3D file format and how to open it | CAD Exchanger
u3d Archives » What Revit Wants
Embed 3Ds into PDF with LaTeX & U3D | Rainnic in the Clouds