Clipping distance in REve visualisation

ROOT
1

Dear ROOT Community,

I’ve been writing an event display using REve by loading a .gdml file using TGeo. The issue is that the geometry is quite large (~100m long) and I therefore get what seems to be clipping effects where my geometry is invisible at a distance and I have to significantly zoom in in order to see it. This is pictured below where, on the left display window, the bottom left of my detector is clipped (I already had to zoom in to see it at all). The top left has my detector being fully invisible.

The workaround I found was to scale down everything by a factor 10 (which is in fact used here, otherwise I am unable to find my geometry even by zooming in). This is done by rebuilding my geometry in TGeo just scaled down.

This however is tedious and quickly gets confusing if we start looking at quantities. Is there an alternative to scaling things down, to increase the clipping distance or another alternative?

Best wishes,

EK

ROOT Version:* 6.38.04
Platform: Arch Linux
Compiler: Not Provided

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image615×510 15.9 KB

Above: zoomed in a little

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image656×524 21.5 KB

Above: zoomed in a lot

2

I hope @alja or @matevz can help you.

3

Dear EK,

The near/far camera updates have been fixed in release v6.40. The change was in client-side code and in RenderCore’s built-in.

Does your environment allow you to move to version 6.40? If not, I will make the patch for 6.38.

Alja

4

Dear Alja,

I’m running off the package (pacman) binary in this instance so I will wait for ROOT to be patched there, it is normally pretty fast.

many thanks for solving the issue while I was having it! I will test everything after the update and confirm whether it indeed fixes the issue.

Cheers,

EK

5

@alja I guess it would make more sense to patch the 6.36 (which will be supported for the next 3 years or so).

6

I can confirm that the Root 6.40.00 changes fix the issue.

Many thanks!

7

Hi,

I have made a PR to backport the fixes to v6-36:

Today I will make a new PR to backport fixes to v6-38.

There have been other fixes and developments since v38. Please contact me if you see any other issues.

Thank you for the report and the testing!

Alja