M3D Software 3D Engine.

Hierarchical Objects / Transforms.
Keyframe Interpolation : Linear / Quaternion.
Freeform Deformation / Vortex Function.
Math Library : Vector / Matrix / Quadratic / Cubic / Hermite / Catmull-Rom / Quaternions.
Shading : Lambert / Gouraud / Phong / Cel Shaded.
Renders : Dots / Lines / Triangles (Plain / Textured) / Billboards.
Texture Mapping Modes : Plain / Spherical.
Curves : Lofted Surfaces / Bezier Patches (Quadratic/Cubic)
Software Pixel Shaders
Supported File Formats : 3DS (ASCII/Binary) / M3D / JPEG / PCX / TGA / MD2 / MD3
Misc : Back Face / Frustum Culling / Z-Buffer / BSP / Alpha Blending / Motion Blur / Anti-Aliasing / Shadows
Written in C/C++ with separate includable X86 assembly tri-fillers for PC. (Approx. 7000 lines of code)

Screenshot of Shading Modes(Teapot consists of approx. 4500 Triangles.
(Phong: The colour of the teapots lid has changed since taking the other screenshots. Can't have people thinking that my phong is wrong :D)