Origin of gOcad
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.
Discrete modeling : a promising alternative to traditional C.A.D
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.
Discrete Smooth Interpolation, gOcad generic mathematical tool for discrete modeling
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.
After a decade of research, the tools developed within the framework of the gOcad project are now well-honed and 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.