OCE (OpenCascade Community Edition) is a community version of the OpenCascade Technology 3D kernel, a C++ library for 3D CAD development. It includes components for 3D surface and solid BRep modeling, visualization, data exchange (STEP, IGES), and rapid application development. OCE aims to fix bugs and improve code quality and portability.
Castle Game Engine is a cross-platform 3D game engine written in Object Pascal. It includes a flexible system of 3D objects, with out-of-the-box levels, items, intelligent creatures, and more. Rendering and processing of 3D models in X3D, VRML, Collada, and other formats is implemented. Many graphic effects are available, including shadows, bump mapping, shaders, mirrors, and screen effects.
Phlipple is a unique puzzle game. The goal of every level is to reduce a 3D shape to a single square. Elimination of squares is done by flipping edges around just like in a cardboard box. It starts off relatively easy to teach the basics, and provides hours of brain tickling fun. It's a great way to train memory as well as orientation in 3D.