[vtkusers] Displaying NURBS surfaces in VTK

[David, John]

The only options I can think of off the top of my head is to use OpenNURBS for definition, subdivision, manipulation, etc., and/or developing a derived class from vtkParametricSpline or vtkSpline.  

At this point I would love to see someone post a definitive answer to why there is no NURBs support now now that there appears to be Windows for GLU 1.3+.  It may be as simple is that there is no funding for the work (which means that we need to help them get funding).  It may be that it already exists in their *commercial* products (which means we need to know the fact and how much the cost is so we can pony up the bucks).  It may be as simple as they do not have the programmers (which means maybe I should hit them up for a Google Summer of Code mentorship together with my old professor Gerald Farin. Now that would be fun summer...  ;-)

Can someone truly in the know post what is up with NURBs as of 4/2008?

  EBo --


-----Original Message-----
From: Marius Erdt [mailto:marius.erdt at gmx.de]
Sent: Fri 4/4/2008 3:32 AM
To: David, John
Cc: vtkusers at vtk.org
Subject: Re: [vtkusers] Displaying NURBS surfaces in VTK
 
Thanks for the reply,

in my case using external tools for displaying NURBS is not an option, 
because my visualization framework is based on VTK. In addition I have 
to modify the NURBS surface during runtime (move control points), so I 
can't switch to an external modeler for that.

I was wondering whether it is possible to calculate the NURBS surface 
from the control points and store that information somehow in a VTK data 
structure to display it at runtime. My question would also be how fast 
that procedure can be performed.

Regards,
Marius

David, John wrote:
> Since no one else has answered, I'll give it a try...
>
> I consider myself a VTK NooB, and too have an interest in using NURBS with VTK.  After hunting around for quite awhile the positive feedback I came across was a suggestion on using OpenNURBS for the surface/spline part, and VTK for the visualization etc.  Taking a look at OpenNURBS and OpenCAM it appears that the GLU problem was solved some time ago (not -- I have not made an in depth study to make sure).
>
> If you just want to render NURB surfaces, I would suggest taking a look a Blender available at blender.org, Rhino, or similar animation packages.  There are also a number of simulation tools like OpenCASCADE which might work too (again I am not sure of the capabilities).
>
> Other than that I think the whole NURBS question would make for a wonderful addition to the FAQ, but when I went to check the VTK FAQ I got a 404 error...  Maybe I'll have better luck later today.
>
> Best of luck, and when you find a solution, will you tell mee ;-)
>
>
>   EBo --
>
> -----Original Message-----
> From: vtkusers-bounces at vtk.org on behalf of Marius Erdt
> Sent: Wed 4/2/2008 3:27 AM
> To: vtkusers at vtk.org
> Subject: [vtkusers] Displaying NURBS surfaces in VTK
>  
> Hello everybody,
>
> I need to display a NURBS-surface in my application which uses VTK for
> visualization.
> There have been a couple of posts on this list regarding NURBS support
> in VTK from late 2004 saying it is not possible due to the lack of GLU
> integration.
>
> Does anybody know if there have been any changes in VTK that enable
> displaying of NURBS surfaces? And if it is still not possible to
> directly view such surfaces, is there any opportunity to make a
> workaround? What I have right now are the control points of the surface
> to be rendered.
>
> Thanks for any help,
>
> Marius
>
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