TGeometry

Class Description

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                    T G E O M E T R Y  description
                    ==============================

    The Geometry class describes the geometry of a detector.
    The current implementation supports the GEANT3 style description.
    A special program provided in the ROOT utilities (toroot) can be used
    to automatically translate a GEANT detector geometry into a ROOT geometry.

   a Geometry object is entered into the list of geometries into the
     ROOT main object (see TROOT description) when the TGeometry
     constructor is invoked.
   Several geometries may coexist in memory.

   A Geometry object consist of the following linked lists:
        - the TMaterial list (material definition only).
        - the TRotmatrix list (Rotation matrices definition only).
        - the TShape list (volume definition only).
        - the TNode list assembling all detector elements.

   Only the Build and Draw functions for a geometry are currently supported.

---------------------------------------------------------------------------
  The conversion program from Geant to Root has been added in the list
  of utilities in utils directory.(see g2root)
  The executable module of g2root can be found in $ROOTSYS/bin/g2root.

  To use this conversion program, type the shell command:
        g2root  geant_rzfile macro_name

  for example
        g2root na49.geom na49.C
  will convert the GEANT RZ file na49.geom into a ROOT macro na49.C

  To generate the Geometry structure within Root, do:
    Root > .x na49.C
    Root > na49.Draw()
    Root > wh.x3d()    (this invokes the 3-d Root viewver)
    Root > TFile gna49("na49.root","NEW")  //open a new root file
    Root > na49.Write()                    //Write the na49 geometry structure
    Root > gna49.Write()                   //Write all keys (in this case only one)
  Note: all keys are also written on closing of the file, gna49.Close or
  when the program exits, Root closes all open files correctly.
  Once this file has been written, in a subsequent session, simply do:
    Root > TFile gna49("na49.root")
    Root > na49.Draw()

  The figure below shows the geometry above using the x3d viewer.
  This x3d viewver is invoked by selecting "View x3d" in the View menu
  of a canvas (See example of this tool bar in TCanvas).
TGeometry

class TGeometry : public TNamed

Data Members

Class Description
