HOWTO: The 50-Pixel Polygon Shading Metric
  
PSS ID Number: Q172828
Article last modified on 09-05-1997
 
IRIX:3.7; WINDOWS NT:3.7
 
IRIX NT WINDOWS
 

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The information in this article applies to:
 
 - Softimage 3D for IRIX, version 3.7
 - Softimage 3D for Windows NT, version 3.7
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SUMMARY
=======
 
The 50 pixel polygon shading is a performance metric used by manufactures
to benchmark their systems (they draw triangles that they know are exactly
25 or 50 pixels in size). In SI3D, when you draw a triangle, the size of
the triangle, in screen space, is incidental. It depends on many factors --
the camera parameters (zoom, position, or interest), the window resolution,
the size of the objects, the angle at which you are viewing them (edge-on
versus perpendicular to them), etc.
 
MORE INFORMATION
================
 
You can perform the following steps to get an approximation of how fast
your card can draw 50-pixel triangles pixels:
 
1. With a 1280 x 1024 version of SI3D running, maximize the top view and
   set it to Shade.
 
2. Get->Primitive->Grid, Polygon, X size 1.0, Z size: 1.0, X Cell Count:
   77, Z Cell Count: 77. Frame selection (f).
 
   The grid should now occupy about 60% of the full screen in the
   horizontal direction (768 pixels) and 75% of the screen in the vertical
   direction (also 768 pixels).
 
3. Click playback to get an approximation of the frame rate (around 13fps).
 
4. Multiply that number by 11858 to get the approximate number of 50-pixel
   triangles per second. Remember that you also have the extra overhead of
   SI3D -- you are not just drawing triangles. So, this can likely give
   significantly lower results than a vendors' benchmark; they are
   measuring one specific thing under very specific conditions.
 
If the frame rate is too high (more than 25fps or 30fps), then the accuracy
of the measurement will not be very accurate. You can also use SI Live for
frame rate statistics.
 
REFERENCES
==========
 
If you have any questions concerning the information contained in this
article, contact support@softimage.com by e-mail.
 
Additional query words: si si3d si3dhard si3dui
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Keywords          : si si3d si3dhard si3dui
Version           : IRIX:3.7; WINDOWS NT:3.7
Platform          : IRIX NT WINDOWS
Issue type        : kbhowto kbinfo
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Copyright Microsoft Corporation 1997.