Hi Mateusz,
[quote="SMesserschmidt"]
When you use instanced drawing you cannot have correct semi-transparent 
objects, as there is no sorting involved.
One option is to sort your instanced obejcts in every frame or to use some 
order independent transparency approach.

[quote]

Could You provide me avaiable techniques in OSG that allow me to introduce 
objects sorting for native OSG objects and instanced ones?
Sorting per object will be done by the scene graph automatically if the stateset contains blending ( @All please correct me here, but I'm not sure about all the details). Usually this is done with DepthSortedBin Renderbin implementation, which you can override and even write your own Renderbin implementation. For starters just rely on the automatic sorting, but beware that is per drawable not per face. So having a semitransparent box will not always result in the desired behavior. This is a complicated topic and there is no general solution to this. If you want to dive deeper into order independent blending look into the examples (osgoit) and look in the mailing list archives/forum. The topic was touch not long ago.

In case of instanced drawing (in case you are using real GPU instancing) there is no ready-to-use implementation, at least non that i know off. I'd start with adding a (cull-)callback to the part which defines your texture/buffer object and implement a kind of sorting based on distance to the camera. It might very well be that there is flaw in my idea, but since I didn't have to solve such problem I leave the experimenting to you.

In general I would say that sorting/semitransparent objects and instancing simply doesn't play well, so maybe you should step back and check if you really need instancing here at all.

cheers
Sebastian

Thank you!

Cheers,
Mateusz

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