Dual Worlds by Ryan Dehaven
An implicit world engine that uses ideas from the dual
contouring paper presented here.
The engine supports different materials for the implicit object and
negative space material. The engine generates polygons from scene with
implicit data. Any implicit data with a inside or outside test can be
supported. Instead of a QEF approximation, a average of the
intersection points is taken for each cell around the object. Objects
are divided into cells using a subdivided structure called an octree.
Negative material example:
Two sphere merging together: