The Blender Game Engine is a component of Blender, a free and open-source comprehensive 3D production suite, used for making real-time interactive content. The game engine was written from scratch in C++ as a mostly independent component, and includes support for features such as Python scripting and OpenAL 3D sound.
Sprite sheet script for Blender VSE. (video squence editor) Convert image sequences to sprite sheet.
Very nice, but has bugs.
If I choose Horizontal and Down the sprite sheet starts not in the upper left corner and the last frame is missing.