[Gmsh] finding problem defining Ruled surface

Mikhail Artemiev artemiev.mikhail at ngs.ru
Mon Jul 11 12:57:16 CEST 2011


Hello, Amin.

>If you don't mind I would like to ask you another question, that is - whether it is possible to define Line >Loops using Spline/Bspline curves which makes a surface with more than 4 edges.

I think it is impossible. The manual sais:

Ruled Surface ( expression ) = { expression-list } < In Sphere { expression } >;
Creates a ruled surface, i.e., a surface that can be interpolated using transfinite interpolation. The expression inside the parentheses is the ruled surface's identification number; the first expression-list on the right hand side should contain the identification number of a line loop composed of either three (!) or four (!) elementary lines. The optional In Sphere argument forces the surface to be a spherical patch (the extra parameter gives the identification number of the center of the sphere).

>I am willing to make a 3D grid around a NURBS surface (in .igs format) which is made up of several >surfaces defined by BSpline curves. I am trying to make those surfaces Transfinite and after making those >transfinite I am hoping to extrude those surfaces so that it makes a 3d grid. But I am finding it difficult to >define those NURBS surface components into Transfinite surfaces (I am trying to make structured grid). 

I'm not sure that I understood your question rightly but I attach an example where I created a Transfinite Surface bordered by four BSpline lines. Hope this helps.

Mikhail Artemiev
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