[vtkusers] Render() method acting slowly

[Lisa Avila]

Hello Richard,

How are you moving the spheres? Most likely you are causing the display 
lists to be recomputed which tends to be slow. When you rotate / translate 
/ zoom you are using the same display list over an over which is faster. 
Try setting immediate mode rendering on for the mappers - this will render 
without display lists which should be faster for moving your spheres but a 
bit slower for the interaction.

Lisa


At 05:25 AM 2/5/2003, Richard Boardman wrote:
>Greetings everyone,
>
>I have a series of spheres (100 or so) which I render in VTK through
>Python. I then reposition all of these spheres, and re-render the window
>using the VTK Render() method. With the phi and theta resolution of the
>spheres set to around 30 each, it will only update the display at around 2
>frames per second. If I reduce the phi and theta resolutions of the sphere
>to just 3, then the update speed is better (~15fps) but still slower than
>I would expect, and it is once more unbearably slow with 300 spheres or
>so. However, if I rotate, pan or zoom the scene with the mouse I get the
>kind of frame rate I would expect, around 100fps, and this is the case
>even on much more complex scenes.
>
>Are there any other ways to 'move' these spheres around which might be
>quicker? After browsing the class documentation for the render window
>stuff I see nothing apparent. My platform is SuSE Linux 8.1 on an Athlon
>XP 1800, graphics adapter is a high-end GeForce 4 using the nVidia SuSE
>drivers.
>
>Just out of curiosity, I removed the spheres and plotted the positions
>with the vtkLineSource method - again, this is quicker (around the same
>speed as the super-low resolution spheres) but unacceptable with larger
>datasets. Is there something obvious that I'm doing wrong?
>
>Thanks in advance,
>
>Richard Boardman                                o o o o o
>Computational Engineering and Design Group      o o o o o
>School of Engineering Sciences                  o o o o o
>University of Southampton                       o o o o o
>United Kingdom                                  o o o o o
>
>
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