Surface tips & techniques

Source:
Don LaCourse, Principal Partner, eDocHelp

The table below lists some of the more common techniques for constructing surface geometry in 3D CAD systems. Please note that this listing is by no means complete. There are many additional advanced surface techniques in use today. Again, our emphasis here is to provide tips for surface construction that can ultimately affect their usage in solid models.

3D CAD Tips

1. Look out for surfaces that have the potential of self intersecting. These include sweeps due to trajectory, revolves due to rotation angle, rules due to curve relationships, and offsets due to curvature.
2. All surface areas have seams (as in a revolve) or boundary curves. When positioned in a resulting solid topology, these seams and boundaries should be located away from other edges or vertices. Vertices or edges should never coexist within system tolerances unless they in fact share common boundaries.
3. Surfaces generated directly from boundary curves such as rules and patched are preferred over surfaces that are excessively trimmed.
4. When possible, always share existing vertices and edges between surfaces.
5. Some techniques such as lofting, meshing, and patching approximate surface curvature between defining boundaries.
6. If possible, when techniques generate new boundaries on surfaces such as with fillets, reconstruct mating surfaces from the new boundaries rather than trimming the existing surfaces.
   Techniques that generate tangent surface edges are recommended even if they result in a trimmed surface.
7. Techniques that generate tangent surface edges are recommended even if they result in a trimmed surface.