| 1 | G3toG4 |
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| 2 | ------ |
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| 3 | |
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| 4 | G3toG4 is the Geant4 facility to convert Geant3 geometries into Geant4. |
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| 5 | This is done in two stages. |
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| 6 | |
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| 7 | First, the user supplies a Geant3 .rz file containing the initialization |
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| 8 | data structures. An executable, rztog4, reads this file and produces an |
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| 9 | ascii ("call list") file containing instructions on how to build the |
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| 10 | geometry. The source code for this is fortran. |
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| 11 | |
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| 12 | Second, a call list interpreter (G4BuildGeom.cc) reads these instructions |
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| 13 | and builds the geometry in the user's G4 client code. |
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| 14 | |
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| 15 | Two examples of how to use the call list interpreter are supplied in |
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| 16 | examples/extended/g3tog4: |
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| 17 | - the first example, cltog4, is a simple example which simply invokes the |
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| 18 | call list interpreter method G4BuildGeom from G3toG4DetectorConstruction |
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| 19 | class, builds the geometry and exits. |
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| 20 | - the second example, clGeometry, is more complete and is patterned after |
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| 21 | the novice G4 examples. It also invokes the call list interpreter, but |
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| 22 | in addition, allows the geometry to be visualized and particles to be |
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| 23 | tracked. Currently, G3toG4 does not provide a method for scoring hits |
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| 24 | in G4. |
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| 25 | |
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| 26 | To build these examples, especially the one involving visualization, the |
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| 27 | user must have one or more of the following environment variables set: |
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| 28 | |
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| 29 | setenv G4VIS_BUILD_<driver>_DRIVER |
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| 30 | setenv G4VIS_USE_<driver> |
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| 31 | |
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| 32 | where the G4-supported drivers are listed in source/visualization/README. |
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| 33 | |
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| 34 | To use the freeware Mesa API, you must have the environment variable |
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| 35 | OGLHOME defined to point to the directory containing the Mesa lib/ directory |
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| 36 | specific to your platform. |
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| 37 | |
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| 38 | To compile and build the G3toG4 libraries, simply type |
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| 39 | |
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| 40 | gmake |
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| 41 | |
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| 42 | from the top-level G3toG4 directory. |
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| 43 | |
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| 44 | To build the converter executable "rztog4", simply type |
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| 45 | |
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| 46 | gmake bin |
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| 47 | |
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| 48 | To make everything, simply type: |
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| 49 | |
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| 50 | gmake global |
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| 51 | |
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| 52 | To remove all G3toG4 libraries, executables and .d files, simply type |
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| 53 | |
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| 54 | gmake clean |
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| 55 | |
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| 56 | the implementation (April 1999) |
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| 57 | ---------------------------------------- |
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| 58 | - PGON, PCON are built using the CSG classes G4Polycone and G4Polyhedra. |
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| 59 | - G3 MANY feature has not been tested. |
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| 60 | - GsROTM is fully implemented and supports rotations and mirror reflections |
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| 61 | - GSPOSP implemented via individual logical volumes for each instantiation |
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| 62 | (G4PVIndexed doesn't exist yet) |
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| 63 | - GSDV* routines for dividing volumes implemented, using |
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| 64 | G4PVReplicas, G4PVParametrised |
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| 65 | - GSROTM is implemented |
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| 66 | - hits are not implemented. Hit code is do-nothing. (It is |
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| 67 | coded up, but hit class references are commented out.) |
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| 68 | The digits+hits code has to be updated before G3toG4's |
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| 69 | hit code can be activated. |
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| 70 | - GSPART has to be updated. |
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| 71 | - Usage of magnetic field class has to be turned on. |
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| 72 | |
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| 73 | the implementation (February 2001) |
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| 74 | ---------------------------------------- |
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| 75 | - Supported shapes: all G3 shapes except for |
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| 76 | "HYPE", "GTRA", "CTUB" |
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| 77 | - G3 MANY feature is not supported. |
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| 78 | - GSDV* routines for dividing volumes implemented, using |
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| 79 | G4PVReplicas, for shapes: |
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| 80 | "BOX", "TUBE", "TUBS", "PARA" - all axes; |
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| 81 | "CONE", "CONS" - axes 2, 3; |
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| 82 | "TRD1", "TRD2", "TRAP" - axis 3; |
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| 83 | "PGON", "PCON" - axis 2; |
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| 84 | "PARA" -axis 1; axis 2,3 for a special case |
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| 85 | Unsupported shapes: |
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| 86 | "SPHE", "ELTU", "HYPE", "GTRA", "CTUB" |
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| 87 | |
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| 88 | the implementation (November 2001) |
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| 89 | ---------------------------------------- |
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| 90 | - Support for G3 MANY feature: |
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| 91 | |
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| 92 | MANY positions are resolved in G3toG4MANY function, |
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| 93 | which has to be processed before G3toG4BuildTree |
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| 94 | (it is not called by default). |
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| 95 | In order to resolve MANY user code has to provide |
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| 96 | additional info using G4gsbool(G4String volName, G4String manyVolName) |
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| 97 | function) for all overlapping volumes. Daughters of |
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| 98 | overlapping volumes are then resolved automatically |
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| 99 | and should not be specified via Gsbool. |
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| 100 | |
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| 101 | Limitation: a volume with a MANY position can have only this |
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| 102 | one position; if more than one position is needed a new volume |
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| 103 | has to be defined (gsvolu) for each position. |
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| 104 | |
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| 105 | See History file for modification history. |
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