Gocad is a 3D modeler dedicated to geosciences. It was developped by a consortium headed by Jean-Laurent Mallet, in the Nancy School of Geology. Gocad is now commercialized by Earth Decision Sciences (formerly T-Surf), a company which was initially a start-up company of the project. Gocad is used by all major oil compagnies (Total-Fina-Elf, ChevronTexaco, Petrobras, ...), and has became a de facto standard in geo-modeling. Laurent Castanié's work (CIFRE Earth Decision Sciences) was successfully integrated in the VolumeExplorer plugin of Gocad.