News

Two weeks since reconstruction mini-workshop, so not many things:

1. TPC plate rendered via textures, ~2 times faster

2. some fixes in kinematics rendering (but decay point still problematic)

3. GUI improvements:

   lens representation of nest-layouts

   fully cutomizable class-views

Event Visualization Framework

Will not repeat the whole story (http://agenda.cern.ch/fullAgenda.php?ida=a051718), but:

1. intermediate representations: digest files and in-memory structures

   combine data for selection / analysis

   VSD — Visualization Summary Data

2. pure ROOT .vs. AliROOT mode

Fiddled with the event-loading code yesterday ... SEGVs possible.

Geometry

Supported operations:

• load and play with it (navigate, modify render style)

  import by regular expression

  import with grouping by common volume

• interface to overlap checking

• export simplified geometry

• save visual representation of geometry

  volume selection, colors

Missing:

• recursive expansion

  encapsulation of whole geometry sub-trees

• photo-realistic (or more beautiful) rendering

GUI demo on simplified geometry:

• Nest navigation: reading the structure, list expansion

  opening and closing of class-views and nests

• Correspondence with implementation: class structure

• Nest layouts

• Pupil navigation: mouse & key bindings

  moving and looking around: M1 & M2 (use the Ctrl button!)

  selection of viewing transformation

• Rendering Modifiers or RnrMods

  render driver provides stack interface for setting properties

  e.g. changing line width of a geometry sub-tree by ZGlBlending RnrMod

Gled docs: http://www.gled.org/docs/

Gled for the impatient: http://www.gled.org/docs/html/gledimp.html

Kinematics

• Particle selection: TParticle + decay point

  Particle Nest layout, Picking, Importing daughters

  Removing unneeded objects

• Changing the data source

• Further options for particle selection

• Modifying rendering parameters: ZParticleRnrStyle

Hits

• Import hits via ZParticle

• Hit selection:

   Float_t  x, y, z;  UChar_t det_ID;  Int_t particle_ID, eva_ID;

• RnrMod example: point size modification with ZGlBlending

TPC digits

• Optimized for memory usage: load from tree, store into GL textures and push to graphics card

• Modifying rendering parameters: TPCSegRnrMod

  somewhat slow

  setting the time slice (also need slice thickness)

  missing: show time graph for pad / pad-row

• Comparing with hits: setting the Near/Far clipping plane

Plans

Release in about a week or two

1. Implement application state with locks against concurrent operations

2. Close-up presented functionality, build against current AliROOT ... deploy binary release

After the release

1. Digits of other detectors

2. Clusters / space-points

3. Reconstructed tracks

4. Combined representation for cross-searches

Contributors and Users

At this stage anybody willing to try-it-out is a contributor (and will get lots of appreciation, support and tea/coffee/beer)

Might be some problems with graphics-card drivers (NVidia & ATI drivers must be downloaded from their site)

Things to do/consider really soon

1. Kinematics: decay-points, end-of-tracking

   Together with some common hit/track-ref representation: could be used as a general Virtual Monte-Carlo visualization suite

2. Intermediate data structures and converters

   Where to put the code ... how to access it from the EVF

3. Thread-safe TFile operations on ROOT level

   Dropped the problem during last 3 months ... but urgent.

4. Gled source integration: provide scripts for downloading and building of core Gled (a lot of it half cooked for Gled distribution building)