Geometry working group

Work items for 2009

Priority List

1. Robustness checking and improvements:
   • Usage of safety on exiting surfaces in navigator
     • Fix behavior of G4Navigator for the treatment of the safety which currently ignores exiting surfaces
   • Review response precision of solids on points close to surface and normals. Verify accuracy of 2^nd order equations
     • Reiterate the tests on surface for random points close to (and far from) the solids' surface, to quantify the precision of the response according to the geometrical tolerance. Verify the conditions under which the surface normal must be computed and the accuracy of the algorithms implemented; identify cases with wrong answers and improve testing
     • Verify where to apply c/(|b|+sqrt(D)) solution
   • Implementation of precise ComputeSafety() in navigation for EM use
     • Review implementation of Computesafety() for use by physics processes (EM) for providing precise computation of the safety value to be not limited by the hard-voxel boundary
   • Interoperability of multiple navigators/geometries
     • Identify critical test cases for use of parallel geometries and combined use-cases (scoring+fast_parameterisation, biasing+scoring, etc..)
     • Review current design and implementation to address remaining open issues
   • Prototype new interface for field accuracy settings
     • Improve existing implementation to allow easier and more intuitive API to users for tuning performance and field response
   • Study adoption of direction in replica navigation
     • Review implementation of G4ReplicaNavigation to take into account of position and direction when locating on egdes or along surfaces
2. Performance tuning:
   • Continue code review for selected CSG shapes
     • Identify places where code is duplicated and could be simplified; study ways of caching calculation of constants and reuse them efficiently; identify hot-spots performance critical
     • Give priority first to most common used shapes, e.g. G4Box and behavior on shared surfaces
3. New features:
   • Customised GDML writer for schema extensions
     • Implement mechanism for allowing for custom extension of the GDML writer for handling of GDML schema extensions in output
   • First prototype of BREPS solids by surface extrusion and rotation
     • Allow for construction of BREPS solids by extrusion and revolution of flat surfaces
   • Extension of G4Region to local magnetic fields
     • Allow for associating magnetic fields to detector regions and propagate the attributes to volumes which are part of the region
4. Documentation:
   • Publication on refereed journal
     • Aim on publishing a paper (pre-print) of the Geant4 geometry modeler, including recent extensions for navigation on regular phantoms geometries on a chosen refereed journal

Previous years planned activities