Fully parametric, partially parametric, conventional and hybrid modeling

[Stefan Harries 3]

Geometric modeling techniques in Computer Aided Design (CAD) can be classified in many different ways (boundary representation vs. constructive solid geometry, discrete vs. transfinite data, regular vs. irregular topology etc.). One classification distinguishes the way shapes are produced and varied:

• Conventional modeling:
  Shapes are defined by data items that are independent of each other and do not bear any task specific information. The polyhedron of vertices that define a B-spline surface is a good example for this.
  

• Partially parametric modeling:
  Changes to the geometry are defined by means of parameters, i.e., a set of modifiers associated with the design task at hand, while the original geometry is utilized as-is (and may come from any suitable modeling process). Morphing is a well-known example.
  

• Fully parametric modeling:
  The entire geometry is defined by parameters, i.e., task specific descriptors which capture the essence of the product to be generated or varied.
  

Ideally, the functionality of your CAD systems allows you to flexibly combine these techniques, essentially leading to a hybrid approach. This is the case with CAESES/FFW.