Visualization of the ROOT 3D class objects with Open Inventor-like viewers

V. Fine (BNL) A. Kulikov (JINR Dubna) M. Panebrattsev (Dubna University) A. Kulikova (MEPHI Moscow)

preface

• This work was done by a group of summer students from Moscow Engineering and Physics Institute (MEPHI), University of Dubna of STAR Group at JINR. • This group is involved in data analysis of STAR experiment at BNL.

• The experiment deals with a huge amount of data. It requires a new approaches to be introduced.

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Why do we need it.

• There is a strong need to introduce new ideas and methods to debug the simulation and track reconstruction software within STAR framework.

• The good portion of computational force (and price) of the modern computer, first of all so-called Desktop PC, belongs its sophisticated video card with advanced 3D accelerators. So far this vast power did not play any major role in the High Energy Physics research due lack of the software that can be feed by the HEP data.

• That can be done by developing the class library to allow using the commercial quality 3D viewers like "Open Inventor" both stand-alone as well as a built-in ROOT 3D viewer to make the cutting / highlighting / selecting pieces of the detectors and events fruitful and ease. It makes possible to see the inner parts of the detector, which usually covered by outer parts. That would create the impressive pictures of events and the detail views of the detectors facilitating the design, simulation and data analysis and representation the huge amount the information flooding the moder n HEP experiments Dec 3, 2003 ACAT03 3

From AGE Geometry Specification to Open Inventor format (IV) Originally the detector geometry is defined by the special language called AGE (Geometry Specification Langugae). AGE (geometry specification language) Macro preprocessor Zebra structure Fortran GEANT3 See next slide C++ object TVolumeView compile GEANT3 Converter to iv format .fz files .root files We solve the problem of the C++ object visualisation by converting it to the .iv format. So You can easily view and manipulate the detector geometry. Dec 3, 2003 ACAT03 Iv files 4

Convertion of zebra banks to ROOT C++ objects

• ftp://root.cern.ch/root2k/pavelR2000.ppt

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ROOT Class library for converting TVolumeView objects to the .iv format.

• • • • We developed ROOT class library which converts the ROOT TVolumeView object to the .iv file. So it is possible to use the standard 3dViewer to see the detector geometry.

The TVolumeView object is a tree of rudimentary shapes described by TBRIK, TTUBE, etc. classes. So our library mainly consists of the special convertor classes for each of this shape (TIVBrik, TIVTube, etc.).

For the round objects (TTube, TCone, etc.) it is possible to set the “CutNumber” which represents what part of these objects you want to see.

Usually it is not necessary to see all parts of the detector, so you can define the depths of the objects in a tree which you want to see.

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ROOT TShape classes

TTRD1 TBRIK TTUBS TPARA TTRD2 TGTRA TTUBE TCONS TPCON TTRAP TCONE TPGON ACAT03 7

Convertor Class Library

TIVBrik TIVTrd1 TIVFile TIVShape TIVPCon TR2iv Dec 3, 2003 ACAT03 TIVTube TIVCone TIVTubs TIVCTub 8

TVolumeView into .iv format conversion example.

{ TR2iv riv(ATLS, 3, 4); // ATLS – Pointer to the TVolumeView object // 3 and 4 is the depth interval in which shapes will be converted TIVShape::SetCut(1) // Sets the CutNumber for the round objects (1 – whole object, 2 half object) riv.Draw(“ATLAS.iv"); // Writes TVolumeView *ATLS into the ATLAS.iv file.

} Dec 3, 2003 ACAT03 9

… TR2iv riv(ATLS, 3, 4); TIVShape::SetCut(1); …

Examples

… TR2iv riv(ATLS, 3, 4); TIVShape::SetCut(2) … In this two pictures you can see how the outer cylinder was cut.

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Detail view of inner part of ATLAS

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… TR2iv riv(ATLS, 4, 4); TIVShape::SetCut(2); … Examples In this case several detector parts were removed manually in the 3d Viewer Here we set the bigger depth level so the outer cylinders disappeared. Than the unnecessary parts was removed using the viewer features.

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Events It is also possible to include tracks to the detector geometry.

Dec 3, 2003 STAR Detector with real tracks ACAT03 13

Results

• Several convertor classes were created.

• It is possible to download the class library and example root file containing ATLAS geometry • In our future plan is to create whole set of convertor classes and some additional features which can help to get a better image of the detector. For example two plane cut of the detector.

• All the suggestions and questions you can send to the [email protected]

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• • STAR Simulation (ppt) (html): Pavel Nevski • ( ftp://root.cern.ch/root2k/pavelR2000.ppt

) • STAR Framework and Visualisation (ppt) (html): Valery Fine ftp://root.cern.ch/root2k/StarFrameWorkAb d3D.ppt

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