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

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

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

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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).
AGE (geometry specification language)
Macro preprocessor
Fortran GEANT3
GEANT3
compile
See next slide
Zebra structure
C object TVolumeView
Converter to iv format
.fz files
.root files
Iv 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.

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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.

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ROOT TShape classes
TTUBS
TBRIK
TTRD1
TCONS
TTRD2
TPARA
TPCON
TTUBE
TGTRA
TPGON
TCONE
TTRAP

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Convertor Class Library
TIVBrik
TIVTrd1
TIVFile
TIVPCon
TIVShape
TIVCone
TR2iv
TIVTube
TIVTubs
TIVCTub
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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
• TIVShapeSetCut(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)
• TIVShapeSetCut(1)

• TR2iv riv(ATLS, 3, 4)
• TIVShapeSetCut(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)
• TIVShapeSetCut(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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Events
It is also possible to include tracks to the
detector geometry.
STAR Detector with real tracks
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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_at_sunhe.jinr.ru

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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/StarFrameWorkAbd3D.ppt