Surface control points


I use Rhinoceros as a preprocessor for Sofistik FEA (Finite Element Method). I made my model in Rhino using the old Maillart’s papers as a Picture Frame in all viewports - Top, Front and Right one.

I’ve got little problem with my bridge arch, because it is curved in two planes. I made it as a intersection of the surface and the solid. The Surface was created from curve in right viewport by curve extrusion. The Solid was created like extrusion of the surface in top vieport. Next I intersected the surface and the solid and got my arch curved in two planes (See picture). I splitted my arch to little parts because I needed to change its properties like thickness and material attributes.

I exported my FEA model from Rhinoceros and recognized that my mesh is bad in one part of the arch. I typed DupBorder command and recognized that border contained many unnecessary control points, which I want to delete. These points influence on my mesh. How to remove them without destroying my arch surface? When I try to delete them, surface changes high ly.

Hi Jarmark- I think I’d look into Rebuild, either of the split up surfaces or of the curves before you make the surfaces- my guess is that ideally you’d probably want make the surfaces as untrimmed, simple surfaces where possible. - the 3d curve from the intersection (btw, look into the Crv2View command) is a guide for making the simple curves you need.


Dear Pascal,

Thank you very much for your reply.

I’ve tried to use Crv2View. It doesn’t work and also create these unnecessary points even if I split my curves before. I have tried to use “Rebuild” command, but my surface changed and doesn’t fit properly to other parts of the arch. Problem is degree of a the surface border and number of its points.

I am figuring how to change degree of curve’s points and its number without changing border conditions of my surface.

What I was thinking is that once the inevitably over-heavy 3d curve is made, chop it up as needed and rebuild the segments with simple matching curves, and then surface from these.


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