[osg-users] Best ways to render "FE" models with millions of tris and quads

J.P. Delport jpdelport at csir.co.za
Mon Nov 16 23:07:46 PST 2009


Hi,

Andrew Cunningham wrote:
> Hi, I am struggling with the most efficient way to render
> "finite-element" models  with the best speed/memory tradeoff. These
> models may have milllions of "nodes" and "elements" ( triangles and
> quads), with usually simple shading. I am replacing some custom
> OpenGL code (hard to maintain, not clean C++) with OSG ( easy to
> maintain, well written C++)
> 
> For example, with one particular model, the old custom  code which
> basically just held a vertex array and sent the primitives down the
> pipeline used about 650M of memory. The OSG version with no
> optimization of the primitives and using display lists used 1.3G of
> memory. Turning on optimization, and turning off display lists
> brought that down to 850M. Turning display lists back on, cost about
> 200M. The big problem with optimizing the geometry , is that one
> loses the ability to pick as all association of the primitive index
> with the original geometry is lost...

Have you tried VBOs instead of display lists? I understand your picking 
problem and would first try to optimise everything that does not throw 
away vertices, i.e. try to share as much as possible. The picking code 
in osgmovie gives an example of how you can get back indices.

jp

> 
> Obviously there is always a memory/speed trade-off here, but perhaps
> someone has been this way before and has some best practices advice.
> 
> Thanks
> 
> Andrew
> 
> ------------------ Read this topic online here: 
> http://forum.openscenegraph.org/viewtopic.php?p=19712#19712
> 
> 
> 
> 
> 
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> 
> 

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