Conclusion
CAD : Geometrical modelling

In this article, we've covered the fundamentals of CAD modelers. The concepts presented, even if they lead to structures and algorithms that can be complex, are relatively well mastered. However, knowledge of these basics is necessary if we are to approach the evolution of CAD towards functional aspects and, in any case, is of interest to users insofar as the models used in CAD lead to advantages and disadvantages which we have attempted to describe. Before we even get into the integration of these modelers into applications, feature-based design and functional design, it's easy to see how important it is to master the main features of a modeler. Three examples illustrate this.

Modeling with NURBS (or, more broadly, parametric surfaces) leads to a number of difficulties, not least because a surface is modeled by a large number of small surfaces that have to be connected...