I’ve been wondering how it would be possible to achieve a light trail effect in animations, ideally via post-processing… would like to know this for both Blender Internal and Cycles if possible. The effect I’m referring to is pretty much a form of motion blur, except the “ghosts” stick around based on the brightness of the object producing them: Normal objects don’t cause any blur, while light sources leave a long hard trail lasting a few frames. Here’s an example image that shows the effect in an exaggerated form:
I figure that at worst, I can just have the light source spawn static halo particles each frame… but that’s an ugly workaround and much more limited compared doing this correctly. Is there such a thing as a light sensitive version of the vector blur node?