[vtkusers] switching between surfaces

[Doug Gehringer]

Hi Folks

I'm new to VTK, to please be patent, I don't know my VTK terminology very well.

I'm working with an application that is trying to animate between a series of 
surfaces.  It wants to display surface 0 on the first frame, surface 1 on the 
second frame etc.  It currently animates by making all of the surfaces active 
and then having an actor change the opacitity of the surfaces with each frame. 
To switch surfaces, the previous surface is made completely transparent and the 
current surface is made complete opaque.

The problem with using opacity to animate is that it causes the OpenGL display 
list associated with the surface to get destroyed and recreated each time the 
surface is displayed.   This leads to horrible performance.  It is about 10x 
faster to display the surface from the display list than to create the display 
list and display it.

Is there a better way to switch between the surfaces?  In other scene graphs 
I've seen mechanisms that select a single child out of the group of children of 
a node.  Does VTK have anything like that?  

Please reply to me directly as well as the list.  I just added myself, but I 
haven't started getting any traffic yet.

Thanks

Doug

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Doug Gehringer     x45938   Ph: 503-626-5938
FastApps Group     Sun Microsystems Inc.
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