1 Reply Latest reply on Jun 7, 2012 2:48 AM by Anna Wood

    Windows emulated OpenGL vs various hardware OpenGL?

    Dale Mahalko

      I know that Windows OpenGL emulation is often just plain awful about curve, arc, and circle precision.

       

      This computer I am testing is about four years old and has an ATI X1300/X1550 series video card, and it is running Windows 7 64-bit. There are no official ATI drivers for this card for Windows 7. ATI considers this card obsolete for whatever reasons of its own, and so the video card is instead using a Microsoft-supplied WDDM driver auto-installed by Windows 7, that doesn't do too much more than make the basic 2D drawing work correctly.

       

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      I am of the opinion that this 3D part rendering isn't supposed to look like this. The blue sketch for this part shows a circle, but the actual part hole is a weirdly shaped hexagon:

       

      File: C:\Program Files\SolidWorks Corp\SolidWorks\samples\whatsnew\drawings\fb10172001.01.sldprt

      Windows OpenGL emulation.png

       

      For the same part along the other side of it, note the smoothly defined sketch edge for the part, outlined in blue, and the actual surface rendering as calculated by Microsoft's OpenGL emulation:

      Windows OpenGL emulation 2.png

       

      The "fun" bit is that SolidWorks does not tell the user that there is a problem here due to using Microsoft's rather shoddy OpenGL emulation. Zooming in and out does not change the poor detail level of these chunky curves.

       

      Imagine a student on their home computer, trying to fit parts together with high precision, and dealing this sort of visual inaccuracy due to a lack of good OpenGL rendering capability, in their home computer's 3D card (if any, for a low-cost laptop or desktop).