[vtkusers] Re: Opacity problems with vtkVolume

[anast.jm at pg.com]

Sorry for the resend....realized the subject line wasn't too descriptive 
in the original post...john

----- Forwarded by John Anast on 06/19/2003 05:15 PM -----

I'm on WinXP with vtk 4.2 from a recent CVS build. I'm not seeing this 
problem. I have a small tcl script that compares side by side the RayCast 
Mapper and VolumePro mapper on the poship volume dataset and the opacity 
it behaving properly for both mappers. What does your volume look like 
after setting all opacity points to 0.0?? ...john




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"Nico Vermaas" <vermaas at astron.nl>
Sent by: vtkusers-admin at www.vtk.org
06/19/2003 02:28 AM

 
        To:     <vtkusers at public.kitware.com>
        cc:     <dsjen at cs.unc.edu>, (bcc: John Anast-JM/PGI)
        Subject:        [vtkusers] Re: vtkusers digest, Vol 1 #1884 - 11 msgs


Hi Dennis,

I have exactly the same problem with 4.x on Linux (Suse 7.3), if you find 
a solution let me know. Will do the same.

Nico
----------------------------------------------------------------
Message: 4
From: <dsjen at cs.unc.edu>
To: vtkusers at public.kitware.com 
Date: Fri, 13 Jun 2003 13:20:01 -0400
Subject: [vtkusers] Volume Opacity

Hello VTK Users,

I'm having trouble changing the opacity of a vtkVolume.  I'm creating 
a vtkPiecewiseFunction and adding the following points to the function 
with the following lines of code, where opacity is a the piecewise 
function:

                 opacity.AddPoint(0, 0.0);
                 opacity.AddPoint(255,0.0);

This should make the volume completely transparent after I set the 
opacity of the volume:

                 ...
                 ...
                 property.SetScalarOpacity(opacity);
                 ...
                 ...
                 actor.SetProperty(property);
                 ...
                 ...

If anyone has any suggestions, needs clarification, or can point me to 
any references, I'd be very grateful.  Also, just for reference, I'm 
using vtk4.0 on WindowsXP.

Thanks,
Dennis



====================================================
Nico Vermaas
ASTRON - Westerbork Synthesis Radio Telescope
Schattenberg 1 - 9433 TA Zwiggelte - The Netherlands

tel: +31 593 598710 
vermaas at astron.nl 
====================================================


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