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Aldeide
09-14-2012, 06:31 PM
Hello,

I've recently started openGL as I need to render nurbs surfaces. I have no issues with a simple surface (20 control points, u and v orders of 4). However when I use my knot insertion algorithm, after several knots have been inserted, the surface won't be drawn. I've checked the data that has been fed to the NurbsSurface function and can't seem to find anything wrong with it. I was wondering if there was some kind of limitation in the nu,ber of control points/knots of the nurbs surface that could be drawn.

I'm using version 4.3.0 with an Nvidia Geforce 560Ti. The program is made using c# and a openGL wrapper, SharpGL.

The first image describes the nurbs surface being drawn. Control points are in red. The large green point was drawn by evaluating a point on the surface and drawing.

http://i.imgur.com/GXfjb.png

After having inserted 200 knots in each u and v directions :

http://i.imgur.com/9mHKL.png

Kind regards,
Anthony