Hi Dakota,

Without knowing more about your model we can't say too much about what
is actually causing the performance to be so poor.  KdTree normally
help with intersection performance in a massive way, and will
typically be hundreds or even thousands of times faster depending on
the nature of the model.

Since you aren't getting speed and slow in the first place I can't
help wonder if there isn't something particular about your model that
is causing problem.  Could it be that you have many long thin
triangles in your scene?

Run you model with osgviewer and bring up the on screen stats by
pressing 's' three times - the will list the scene stats.  How many
geometry, primitives and vertices do you have in the scene?

Robert.

On 14 December 2011 09:40, Jen Hunter <jenr...@web.de> wrote:
> Hi,
>
> I'm curious about the time it takes to do intersection testing.
>
> I have roughly 800 Image points that I need to check for intersection with my 
> model.
> My model isn't really complicated, it's basically just a huge box with a few 
> rectangular elements that stand out a bit.
> It was created using Sketchup and is in Collada file format. I use the method 
> computeIntersections. I'm working with OSG 2.8.2.
>
> However, even with kdtree support it takes about 120 to 190 ms to test for 
> the 800 intersections.
> Without kdtrees it takes up to above 400 ms. I'm confused that it varies so 
> much when the setup of the scene I tested was always the same.
>
> I am by no means an expert in computer graphics, so I ask you.
> Is it normal that it takes so long even for kdtrees, or is it likely that I 
> do something terribly wrong?
>
> Thank you!
>
> Cheers,
> Dakota
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=44379#44379
>
>
>
>
>
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