Composite Curves and Surface Tangency

[dgschaefer]

WF4, M190



I think I know the answer here, but thought I'd ping the group to see if
there's something I'm missing.



When building a boundary surface, it is often advantageous to create an
approximate composite curve (copy) of your driving curves and build from
that rather than the original curve feature. This eliminates all the
internal vertexes in the curves that create internal edges in the
boundary surface and frequently results in a 'cleaner' surface.



However, if you need tangency to adjacent surfaces, there's no way to
define tangency from the single composite curve to the multiple adjacent
surfaces. So there's no way, that I've found, to use the approximate
composite curves to get a smoother form and maintain tangency to
multiple adjacent surfaces. Is that correct, or am I missing something?



Doug Schaefer

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[DeanLong]

Doug,

You are correct. The approximate curve removes your ability to specify a tangency condition across the surface boundary. However, if you have the ability to redefine your older surface to use the new approximate curve...you are laughing. I use this technique often when I need to get the surface "sweet" and correct.

Secondly, just food for thought. In order to have the ability to specify the tangency across the boundary using exact curves, your vertices should be coincident for both surfaces. I have had very limited "random" situations where I was able to specify C1, with the "pieces" not lining up explicitly. but that was a case of being lucky, not good.

Dean