Subdivide / Unsubdivide addon for - FlippedNormals
How to un-subdivide or undo subdivisions in Blender - Artisticrender.com
Pablo Dobarro on Twitter: "Multires can now unsubdivide and rebuild lower resolution base meshes. With this feature, you should be able to import projects from other software with all subdivision levels available. #
How to SUBDIVIDE a 3D model in Blender }
modeling - Is there an unsubdivide function in Blender? - Blender Stack Exchange
uv - Un-Subdivide - Remove loops on one axis - Blender Stack Exchange
Subdivide — Blender Manual
How to reduce polygon in Blender - cgian.com
modeling - Is there an unsubdivide function in Blender? - Blender Stack Exchange