Quick demonstration of a dual contouring modifier in Blender.
This is based on code contributed by Dr Tao Ju, full info in Ton's email here: lists.blender.org/pipermail/bf-committers/2011-March/030758.html
The input model is the famous Stanford Bunny. As shown in the first part of the video, this is a scanned mesh composed of triangles, with noticeable seems where scans were joined together, as well as several holes.
The new remesh modifier essentially passes DerivedMesh data out to the PolyMender code, which does all of its magic, and then writes it back out to a new DerivedMesh.
The result is a mostly-quad mesh, with holes filled. The level of detail is adjustable by setting the depth of the octree; at higher levels it reproduces the details of the original mesh very accurately.
Still some things yet to do: efficiency improvements, add controls for more features in the external code, better output of non-quad/non-tri polygons, and fix some crashes...
Overall a pretty quick addition though, thanks a lot to Tao Ju for contributing this :)