Wednesday, December 15, 2010

Blender Ogre Collision Panel

Triangle count may not be much of an issue for rendering, but it still remains a bottle neck when doing collisions even with fast libraries like Bullet. The exporter uses blender-game-engine (BGE) collision primitive types; or a second proxy-mesh can be parented underneath the display mesh, and then the proxy is substituted as the triangle mesh for collision. Collision primitives are of course the fastest option. By default Blender does not display the bounding type when a BGE collision primitive is choosen, so the collision panel seen here will do the extra work and display the correct bounding type so that the user can get visual feedback of their changes. If the collision type 'Triangle Mesh' is chosen, the object is set to show wire-frame over shaded. (note there is a bug in blender 'Capsule' type may not show)

Setting a proxy-mesh for triangle collision can be done manually by the user, but this is error prone, so the interface automates this process by doing the following: copies object, parents, locks translation, renames to 'collision', and then applies a decimate modifier. The decimate modifier is then controlled from the parents panel.