[osg-users] Improving performances

[Werner.Modenbach at texion.eu]

Hi Alex,
I'm doing simulations of textile structures and work with yarn objects being deformed according to Bentsen stretches etc.
The number of triangles is also extreme. I have a COUPLE bound version doing the geometries by CPU threads and a second version working with geometry shades. Both versions have their pros and cons. But performance wise the second version is far the best - at least with a very good graphics card. 
I think the biggest advantage is the dramatically reduced amount of data to be transferred. This results in immediate appearance on the screen and reduced processing time for culling etc.
Also with vertex parameters I can control the geometry shades. In this case vertices are just center line polygon points.
May be this helps you in finding your best approach. 
Werner

On 15. Februar 2017 16:03:12 MEZ, Ale Maro <sasha71 at teletu.it> wrote:
>Hi,
>
>I posted some question about OSG performance in the past and now I
>would like to definitively improve visualization performance of my
>application.
>I want to say that now I already have very good performances with OSG
>but now I need to start thinking how to manage also some "extreme"
>scenes.
>
>It is a CAD-like application and a possible scene is composed by some
>objects (let's say from 1 to some hundreds) each one with 100K to some
>millions of triangles. 
>Each of these objects can have up to some thousands of children each
>one with around 100 triangles.
>For all objects I use vertexbuffer instead of display lists to reduce
>waiting time at first draw (due to display list compilation).
>I use a matrixtransform for each object and few groups for all the
>scene.
>Normally objects are not modified but sometimes they can be modified on
>the fly by user. So I did not set DataVariance (I supposed it is set
>automatically to STATIC if I did not modify an object).
>The application is GPU bounded as I can see from on-screen stats.
>
>I cannot merge objects or groups into one becouse I need to do some
>operations on them so I need to keep them separated.
>I am using KdTrees to improve object picking, it now works well but the
>interaction is still not smooth becouse of the slow frame rate.
>I think I cannot use LODs becouse triangle reduction on-the-fly can
>take very long time on this type of scenes.
>I tried with osgViewer and more or less it have the same performance of
>my application.
>At the moment I can just show bounding boxes for raw scene manipulation
>but often I need to show object details.
>
>Could you give me some hint to improve performances? I hope information
>I give you are enough to do a first analysis.
>At the moment I am not able to setup such a scene to send you
>screenshots of the stats but I can do it in next days if needed.
>
>Thank you in advance.
>
>Best regards,
>Ale
>
>------------------
>Read this topic online here:
>http://forum.openscenegraph.org/viewtopic.php?p=70200#70200
>
>
>
>
>
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