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)

Dec 3, 2003 ACAT03 2

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

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From AGE Geometry Specification to Open Inventor format (IV)Originally the detector geometry is defined by the special language called AGE

(Geometry Specification Langugae).

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.

AGE (geometry specification

language)

Macropreprocesso

rFortran

GEANT3

compileGEANT3

Zebrastructure

C++ objectTVolumeView

.fz files

Converter to iv format

.root files Iv files

See next slide

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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.

Dec 3, 2003 ACAT03 7

ROOT TShape classes

TBRIK

TPARA

TGTRA

TTRAP

TTRD1

TTRD2

TTUBE

TCONE

TTUBS

TCONS

TPCON

TPGON

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Convertor Class Library

TIVFile

TIVBrik

TIVPConTIVShape

TIVTube

TIVCone

TIVTubs

TIVCTub

TIVTrd1

TR2iv

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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.}

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Examples

…

TR2iv riv(ATLS, 3, 4);

TIVShape::SetCut(1);

…

…

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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Examples…

TR2iv riv(ATLS, 4, 4);

TIVShape::SetCut(2);

…

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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EventsIt is also possible to include tracks to the detector geometry.

STAR Detector with real tracks

Dec 3, 2003 ACAT03 14

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 mpanebr@sunhe.jinr.ru

Dec 3, 2003 ACAT03 15

• 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/StarFrameWorkAbd3D.ppt