Ok, so, if we accept this definition Rhino3D it’s perfectly able to do Class A srfs.
Other it’s explicit srf ability.
Yes.
Controlling, matching and validating multiple Bezier patches is not easy though and in some cases not possible.
If you look at some Alias tutorials you’ll see that it has more tools to do this sort of thing although the process to achieve perfect blending is still difficult.
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Nice to finally see a material definition of Class A, and it’s a simple one too. Out of interest Phil, what degree do surfaces typically get taken to in automotive work to achieve single span?
Phil, can you give me the links to the Alias tutorials on Class A surfaces?
This depends to a large extent on the matching. Let’s assume you have a four sided surface patch and you want to match all edges to G3 then you have 8 control points in U and V already so if you add another point to control the shape at the middle of the span then you have a Degree 8 surface by default.
I’m out of my office for a few days. You’ll find them easily enough on Google. There’s some official Autodesk stuff there. These are actually quite helpful for Rhino users.
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Matt, the trick is not to go past degree 7 as far as i know, 5 is even better, for instance if you would have a blend between 2 surfaces, you would have to make sure that the 2 surfaces make it as easy on the blend as possible, what i mean by that is that the shape of the 2 surfaces would allready lead in to the blend, G3 doesnt necesserily mean that all surfaces need to be atleast degree 7 or higher, it has to do with the transition from surface 1 to 2 which can be degree 5 or even 3, anybody can correct me if im wrong on this but this is how i learned it, maybe not perfectly explained,…
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on http://www.forum.amicocad.it/viewtopic.php?f=30&t=43 there is an article written by Fulvio Romano on the theory of curves, very very interesting. You may find answers to many questions. The article is in Italian, but with google you should have no difficulty.
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