The open source mesh processing system
The open-asset-importer-library repository
Interactive 3D Layout Viewer for GDSII
An interactive viewer for three-dimensional chemical structures.
Rayshade raytracer
Viewer and exporter for Unreal Engine 1-4 assets
3D .NET engine for Windows, Linux, Mac
3D File format viewer/explorer
Simple 3D viewer
osGraphX is a 3D file viewer based on openscenegraph.