3d Surfacing

In 3D surface modeling, the mathematical control points (CV's) are displayed and can be controlled by the modeler. This control of the CVs allows to determining curves and surfaces 100%.

The intervention in these CVs is only possible with a few CAD programs.

The following example of a simple parabolic curve shows the influence of these CV's on curves.

Of course, all surfaces also have these CV's and can be edited just like the curve.

However, here the effect is 3-dimensional and has an enormous influence on the highlight of the surfaces.

The following GIF shows the effect.

Since each CV can be moved individually, the number of CVs per area should be carefully selected.

  • Too many could easily effect the surfaces with "dents"
  • Too few allow only a certain curvature.

Therefore it is not advisable to generate the complete model from only one surface. but to divide the model into individual surfaces, called surface patches instead.

In the following example, I will show you the step-by-step connection of the left surface onto the existing right one. After all the necessary CVs are corrected the highlight is correct.


This should give you a brief insight into the 100% control of the 3D Surfacing

As already mentioned, there are many theories waht a surface patch has to look like. The following points determine whether this is correct or wrong: 

  1. The geometry corresponds with the concept of the designer / customer
  2. Perfect highlights without errors
  3. The surfaces are able to offset
  4. Data exchange with the toolmaker is possible without problems.

In order to fulfill these 4 points, however, it is not only necessary to have an excellent 3D imagination, but also to have a lot of practical knowledge in the field of surface science. In this case handling of the CAD software is here the easiest part.

With the help of the following pictures depicting the surface patch of my car and the individual control points of the surfaces, you can easily see where surfaces have to be divided.