Motivation: Inadequation of traditional C.A.D tools used in geomodeling
During the eighties, it became clear that, in spite of their success in modeling simple surfaces, traditional automatic mapping systems would never be able to model complex surfaces and, more generally, complex geological volumes affected by severe tectonic events with overturned folds, salt domes and reverse faults. At the same time, experience using traditional Computer Aided Design software developed for the car industry brought out its inability to accommodate the complex data encountered in the geosciences.
Approach: Discrete modeling and Discrete Smooth Interpolation
For this reason, within the framework of the gOcad research project, a completely different strategy involving the discrete modeling of natural objects was proposed in 1989. In this discrete approach :
- the geometry of any object is defined by a finite set of nodes (points) in the 3D space,
- its topology is modeled by links bridging these nodes,
- its physical properties are modeled as values attached to these nodes.
For example, if the object to be modeled is composed of surfaces, then the links can be arranged in such a way that the mesh so defined generates triangular facets. These facets can be interpolated locally by flat triangles or, if needed be, by curvilinear triangles. It is not difficult to imagine how this strategy can be extended to the modeling of curves and volumes.
In practice, such a discrete approach is of no interest without a powerful mathematical tool able to interpolate the physical properties and the location (x,y,z) of the nodes defining the objects in the 3D space. For this reason, Jean-Laurent Mallet has proposed a very powerful new method, called ``Discrete Smooth Interpolation'' (DSI), which today is at the very heart of the gOcad research project. This new interpolation method was specially designed for modeling natural objects, while taking into account a wide range of complex and more, or less, precise data.
In fact, adopting a new mathematical core for a Computer Aided Design system has huge consequences which render inadequate most of the existing tools developed for traditional systems. The new research fields thus opened up resulted in the launching of the gOcad research project in the fall of 1989. This project was supported by the Phase I Gocad Consortium, and involved a community of students, engineers and researchers from the member intitutions of the Consortium managed by ASGA.
After a decade of R&D, the tools developed within the framework of the gOcad project became widely used in the oil and gas industry for modeling complex geological structures in the sub-surface. At the same time, some exciting applications have came to light in very different fields such as, for example, medecine, anthropology or the environmental sciences.
As a result of the R&D project involving all the members of the Gocad Consortium, the spin-off company T-Surf was created in 1998. T-Surf acquired the property on the Gocad Software from the Consortium, and became in charge of software maintenance and evolution, consulting activities, etc. T-Surf, founded and directed by Jean-Claude Dulac, a former student of Jean-Laurent Mallet at the Nancy School of Geology, grew from a team of 10 people in 1998 to about 250 employees in 2006. After a name change to Earth Decision Sciences in 2002, this company merged with Paradigm Geophysical in 2006.
Since 1998, the mission of the Gocad Consortium is to focus on research tasks to advance the state of the art in Geomodeling. Most of this R&D is implemented as plugins to the commercial version of Gocad, and can be used by all members as specified by the Phase III Gocad Consortium Agreement.