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The V-Atlas Event Visualization Program

The V-Atlas Event Visualization Program. J. Boudreau, L. Hines, V. Tsulaia University of Pittsburgh A. Abdesselam University of Oxford T. Cornelissen NIKHEF J. Hoffman Southern Methodist University, Soltan's Institute for Nuclear Studies W. Liebig CERN

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The V-Atlas Event Visualization Program

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  1. The V-Atlas Event Visualization Program J. Boudreau, L. Hines,V. TsulaiaUniversity of Pittsburgh A. AbdesselamUniversity of Oxford T. CornelissenNIKHEF J. HoffmanSouthern Methodist University, Soltan's Institute for Nuclear Studies W. LiebigCERN R. McPhersonUniversity of Victoria/IPP E. MoyseUniversity of Massachusetts A. SalzburgerLeopold-Franzens-Universitaet Innsbruck M. ThioyeState University of New York atStony Brook I. TriggerTRIUMF CHEP 2006 TIFR, Mumbai

  2. Introduction • V-Atlas is the Event Visualization program integrated into ATLAS analysis framework ATHENA • V-Atlas is based upon Open Inventor and it’s HEPVis extensions • V-Atlas co-displays the real Detector Description/Simulation geometry together with event data • V-Atlas renders in real time on regular laptop computers, using their available graphics acceleration. • No commercial software is required • V-Atlas has been also actively used as a powerful debugging tool in various domains of ATLAS s/w • Detector Description, Simulation, Reconstruction

  3. What Is Open Inventor? • The Open Inventor is a free, object-oriented 3D modeling toolkit, developed by SGI • The Open Inventor is a library of objects and methods used to create interactive 3D applications • Scene Database, Node Kits, Manipulators… • The Open Inventor uses OpenGL for rendering, takes advantage of hardware acceleration in the graphics card • Frame rates of 100/s are not uncommon, but that depends on platform and complexity • It can be extended to meet new needs • And it is very well documented. Two books by J. Wernecke and The Open Inventor Architecture group • “The Inventor Mentor” – toolkit description • “The Inventor Toolmaker” – guide to extending

  4. HEPVis – an extension to the Open Inventor • The HEPVis project started in 1996. The main goal is to provide HEP specific extensions to the Open Inventor • These extensions are called Hepvis Library • HEP specific shapes, like helices. GEANT shapes • “Smart Nodes” which can handle their own X-events • HEP specific viewer, based on Open Inventor viewer • Hepvis is an open library, it can expand • New shapes or other objects • The Open Inventor and its HEPVis extensions are well suited to the requirements of an interactive event display

  5. V-Atlas architecture • V-Atlas consists of two main ATHENA modules • GeoModelGraphics – V-Atlas ‘core’ module • HitDisplay – extensible module • HitDisplay module at initialization instantiates what we called an “embedded master”, which is a framework-within-a-framework • The ATHENA framework handles events and database I/O, configuration options, loading of modular services and algorithms • The Embedded Master provides a framework for visualization roughly defined as “translating abstraction into geometry” • HitDisplay module consists of several Systems, each serving its own special purpose • Geometry System, Hit Display System, Calorimeter System, Track Parameters System, Template System and others

  6. V-Atlas architecture How do the HitDisplay Systems work? • V-Atlas user selects at run time which systems he/she wants to use • The selected System is called at each event. It has access to the Transient Object Store within ATHENA framework – the Store Gate • The System is supposed to translate the Store Gate objects (hits, digits, tracks etc.) into geometry • In addition, the System may do something when the object is clicked • Print object specific information to the text box • Each System is accompanied by its personal Controller, which provides GUI for System methods • Menu items, dialog boxes etc

  7. V-Atlas architecture How to extend V-Atlas functionalities? • The functionality of V-Atlas program is extended by creating new Systems or developing the existing ones • The modular structure of the V-Atlas allows independent development of HitDisplay Systems • V-Atlas contains a special Template System which provides a good starting point for new developers • When one runs the display and launches the template system it prints out the information on how to clone and extend the template system • The users of V-Atlas can develop private Systems addressing their specific requirements and use these Systems for analysis & debugging

  8. V-Atlas Systems - Geometry • The earliest systems to be used within V-Atlas wereGeometry System, Measurement System, Hit Display System • The entire ATLAS DD geometry is visible • Users can switch pieces on or off • Users can navigate volume hierarchy up and down • Users can iconize pieces that get on their way • It is possible to determine the software weight of any object • This functionality does not work yet for Boolean solids • Users can print volume identifiers – names and ‘copy numbers’ – at selection • Users can get volume transformation in the local coordinate frame • If some volume is declared as ‘Alignable’, it is possible to manipulate with its position interactively

  9. V-Atlas Systems - Geometry • The earliest systems to be used within V-Atlas wereGeometry System, Measurement System, Hit Display System The various information about selected volumes is printed out in the text box

  10. V-Atlas Systems - Geometry • The earliest systems to be used within V-Atlas wereGeometry System, Measurement System, Hit Display System One can interactively move the Alignable volume … … and get alignment characteristics

  11. V-Atlas Systems - Measurement • The earliest systems to be used within V-Atlas wereGeometry System, Measurement System, Hit Display System

  12. V-Atlas Systems – Hit Display • The earliest systems to be used within V-Atlas wereGeometry System, Measurement System, Hit Display System Hit Display system played very important role in verifying the integrity of the geometry description and simulation. That was done by relocating hits in space using the geometry plus local coordinates of the hits.

  13. V-Atlas Systems – Extra Input • GEANT4 can print in the log file positions of potentially dangerous points in geometry description • It is possible to format them up as .iv or .wrl file … • … and then feed to V-Atlas in order to co-display with detector geometry • V-Atlas is not just a viewer, it can act as a browser for VRML

  14. V-Atlas Systems – Calorimeter Energy in ATLAS Hadronic Tile Calorimeter cells, with adjustable threshold

  15. V-Atlas Systems – Tracking, Surfaces

  16. V-Atlas Systems – Banks

  17. V-Atlas Systems – Calo Clusters, Tracks

  18. V-Atlas Systems – Digits

  19. V-Atlas Systems – Beam Spot

  20. V-Atlas as a debugging tool ‘Strange’ simulated event. It took forever to simulate… The visualization showed the problem immediately.

  21. V-Atlas – Final Remarks • V-Atlas, initially born as a rubric under the general task of ATLAS detector description, has gradually turned into a multifunctional Event Display program • Thanks to its modular architecture V-Atlas is evolving permanently by including new functionalities developed by specialists of various ATLAS software domains • V-Atlas is extensively used as a debugging tool for Detector Description software, Simulation and Reconstruction algorithms • We are also going to install and use V-Atlas as an Event Display at ATLAS Point 1 • … More information on our web site http://boudreau.home.cern.ch/boudreau/v-atlas-hepvis.htm

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