[vtkusers] Rendering of PolyData having normals since release 3.1

[Francis Bouchet]

----- Original Message -----
From: Francis Bouchet <francis.bouchet at areall.com>
To: <vtkusers at public.kitware.com>
Sent: Wednesday, May 16, 2001 3:45 PM
Subject: [vtkusers] Rendering of PolyData having normals since release 3.1


> Hi all,
>
> I have a very simple portion of tcl script which worked fine with vtk2.4
and
> which has trouble since I changed to vtk3.1 :
> I try to visualize a PolyData and when the Rendering window appears I
don't
> see anything. After actionning the interactor, the volume is displayed;
but
> in some case it is so dark that I can't see it : it is as if it was not
> lightened. I tried to change it's colour, but it always appears completely
> dark.
> Sometimes it is as if the inner surface was couloured and the outer
surface
> not, but I did not succeed in finding whet is going wrong :
> I tried to set BacfaceCulling on and Frontface Culling on, but it does not
> solve the problem.
> All what I noticed is that this problem is linked to the normals of my
> PolyData : if I clear the normals section in the input data file, the
> surface is then correctly displayed. In my C++ application I wrote a
routine
> inverting normals, but it does not work for all situations :
> sometimes, I need to invert normals of a PolyData in order to be able to
see
> it in a Rendering window (whem I try to visualize it at the same time as
an
> other Actor) and when I try to visualize it alone in its Rendering window
I
> don't need to invert the normals, and sometimes it's the opposite.
> In some cases, I can't see two actors at the same time (even by inverting
> normals of one or both Actors).
>
> As you can notice, I did not succeed in localizing the problem and it's
very
> disturbing.
>
> Could somebody help me please ? The corresponding tcl script is attached
to
> this mail and it is very simple and short. I guess the problem comes from
> the data but ...
>
>
> Thank you in advance,
>
> Francis.
>
>
____________________________________________________________________________
> _____________
>
> Francis BOUCHET
> AREALL
> 24, rue Bailey
> 14000 CAEN
> FRANCE
> tel  33 (0)2 31 46 36 00
> fax 33 (0)2 31 46 36 09
>
>
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