Normal Baking from Multires Modifier

I’ve been sculpting a model with the multiresolution modifier and am now trying to bake the texture. I have been going to the bake panel and selecting the “bake from multires” checkbox but I always get the error that “multires baking requires a multi-resolution object”.

I have prepared an image for it to bake on, but I don’t seem to understand how it works. I’ve searched through the web, but I can’t find any tutorials to explain how baking from the modifier works. Can someone explain it to me or point me to a tutorial that would be of use?

I’ve also attempted to bake it the “normal way” by copying the mesh, deleting the modifier on the copy, and then applying it on the original. I put them both in the same place and from there I’ve tried baking from “selected to active” but this method always gives me a blank map.

EDIT: Suddenly the “normal way” is working. Strange… But it’d still be nice to see how multires works.

It bakes the normal map between the highest multires level and the preview level
Demo: http://screencast.com/t/kHeNh3Tsh4Zu

http://code.blender.org/index.php/2011/06/baking-from-multires-data/

Thanks for the video that was helpful. It looks like my problem was having a subsurf modifier after the multires.