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TGeomanager GDML hole on a pad with OpenGL

Hi all,
I have a simple geometry to show with openGL.
It is a trap pad with two holes on it. The problem is they look different from
different angles. It seems one of the holes are not through but with a thin layer
on one end.
Is this just a display problem? Or how can I avoid this?
Thanks a lot.

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It would help if you can provide geometry file.


Hi Sergey,
Thanks for the quick response.
It is a huge file, and I choose this single volume to display with open GL.
Here is the code for the related part.
It seems when I increase the thickness of the pad(z in _STMShield_front_Al0x32a72a0), everything looks fine.
But I do need to keep this small.

code:code.txt (1.1 KB)

It looks similar to ROOT-7981.


First of all, here is complete gdml file for testing.
work.gdml.txt (1.8 KB)

And yes - seems to be ROOT geometry rendering has problem in correct visualization of such composites. But composite itself looks fine. If I check it with JSROOT - works correctly:

All components

There is no touching surfaces - everywhere clear cuts.
I fear this bug will be difficultly to fix.


Here problem with “complicated” composite shape. It has very many components and CSG algorithm just breaks calculation at some complexity level. As a result - one gets incomplete and partially corrupted sets of triangles. Unfortunately JSROOT has similar problem as well with that geometry.

1 Like

Hi Sergey,

Thanks for completing the gdml file.
This file works good in ROOT.
Then, I think the problem only happens when this composite is nested in another big geometry.