[vtkusers] about using Nurbs to approximate scattered points as a free surface

Randy Heiland heiland at ncsa.uiuc.edu
Tue Sep 10 10:36:37 EDT 2002

On Sep 10,  9:36am, feng_1999 at eyou.com wrote:
> Subject: [vtkusers] about using Nurbs to approximate scattered points as a
> hi,all
> I know the vtkSurfaceReconstructionfilter which can fit the job about
> reconstruction from unorganized points' well.
> But now,I want to use gluNurbsSurface to do the job.Then,how to transfer the
> scattered points P to the control points V using vtk.By the way,is there
> better way?

For starters, I think you're comparing apples to oranges.
 vtkSurfaceReconstructionFilter is, as you say, a filter that operates on an
unorganized point set, i.e, no constraints (we'll not discuss the issue of how
well it does this).  However, gluNurbsSurface (a parametric surface) does in
fact have constraints, e.g., from its man page:

control (points)
    Specifies an array containing control points for the NURBS surface. The
    offsets between successive control points in the parametric u
    and v directions are given by sStride and tStride.

Perhaps you need a tool that can, given a polygonal surface, generate the
parameters for an approximating NURBS surface.  Googling for 'nurbs
approximation' has some interesting hits.


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