nurbs

f-kosche's picture
f-kosche
Mon, 10/23/2000 - 09:31
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Other usage issues

Hi everybody, i might not understand all correctly, but is there support for nurbs surfaces in open cascade ? if not, are there plans to support them in the future ? so long florian

Mikael Aronsson's picture
Mikael Aronsson (not verified)
Mon, 10/23/2000 - 10:25

Hi !

Yes nurbs are supported ny OpenCascade, for example the Geom_BSplineSurface will do it.

A nurb is just a special case of a spline surface, to put it simple a nurb surface is a spline surface with none rational control points, you do this by adding "weights" to the control points, for an ordinary spline surface all the weights are 1.

Mikael

Mikael Aronsson's picture
Mikael Aronsson (not verified)
Mon, 10/23/2000 - 14:00

Hi again !

Hmmm, I was in a hurry the last time, and the description I gave is not very correct, sorry.

A nurb is a Non Uniform Rational Bspline curve to be correct, non uniform means that the knot span between two knots may not be uniform through the knot vector, and a rational curve/surface is when you have weights <> 1.0, if you do this then it becomes a nurb curve/surface. And all this is supported by the spline curves in Open Cascade.

Use SetWeight/Weight to set/get the weights.

Mikael