Event Manager not streaming Geometry scene

Newbie
1

Hello I am a first year college physics student and I want to setup the display of a simplified detector/particle tracking system. The script I describe below ran into a snag and as I am in the initial stages of learning the ROOT package, I could use some help.

My intent is to display a cylindrical geometry and a few random particle tracks, however the attached script is not rendering my cylinder, only the particle tracks. (see attached script => pbr_4trk.C (3.1 KB) , and output => pbr_4trk-output.txt (2.5 KB) , and geometry file => CylGeo.root (7.5 KB) )

Specifically the Event Manager is issuing this message:

‘’’ EVEMNG … streaming scene [Geometry scene]
sending json, len = 634
NOT sending binary, len = 0 ‘’’

and even in the Event Visualization Environment I am unable to toggle the view on.

I am certain there are more efficient ways of approaching this, please feel free to recommend a completely different approach. Since I am at the very ground level (I read the Basic-Course slides, perused the Class Reference Docs, etc.) any specific suggestions, or brief general pointers to put me on the right track are appreciated.

Additional point: as you can see, I am saving my geometry to file, but I can see that the object is already present in the ROOT browser. What would be a way of referencing it directly without having to go through the saving and rereading step?

Thank you for you time!

ROOT Version: 6.22/02
Platform: Debian 10
Compiler: g++/gcc version 7.3.0 (crosstool-NG 1.23.0.449-a04d0)

2

@linev could you please take a look or maybe suggest who can help here?

3

Hi,

Yes, it is indication of the problem. Zero binary size here means that no any points from geometry scene transported to the client. I am not an expert how to correctly create all shapes and volumes for REveManager class, but did you try to follow event_demo.C example? It has function makeGeometryScene() where some primitive shapes are created. As I can see, one should use REveGeoShape class. Probably, there is a way to convert existing TGeoManager into REve classes.

More detailed information you may get from our REve experts - @alja and @matevz, but please take into account 9 hours time zone shift compared to European time.

4

@oshadura Do you need to create geometry using TGeoManager? If not, you could create TGeoShape directly without TGeoManager https://github.com/alja/root/blob/varcol-multi/tutorials/eve7/event_demo.C#L209-L219