1 | <html> |
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2 | <head> |
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3 | <title>ADG: Geometry</title> |
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4 | </head> |
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5 | |
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6 | <!-- Changed by: Gabriele Cosmo, 18-Apr-2005 --> |
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7 | <!-- $Id: geomReflection.html,v 1.2 2006/06/09 13:57:14 gcosmo Exp $ --> |
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8 | <!-- $Name: $ --> |
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10 | <table WIDTH="100%"><TR> |
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11 | <td> |
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12 | <a href="../../../../Overview/html/index.html"> |
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13 | <IMG SRC="../../../../resources/html/IconsGIF/Overview.gif" ALT="Overview"></a> |
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14 | <a href="geometry.html"> |
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20 | </td> |
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21 | <td ALIGN="Right"> |
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22 | <font SIZE="-1" COLOR="#238E23"> |
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23 | <b>Geant4 User's Guide</b> |
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24 | <br> |
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25 | <b>For Application Developers</b> |
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26 | <br> |
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27 | <b>Geometry</b> |
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28 | </font> |
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29 | </td> |
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30 | </tr></table> |
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31 | <br><br> |
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32 | |
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33 | <a name="4.1.7"> |
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34 | <h2>4.1.7 Reflecting Hierarchies of Volumes</h2></a> |
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35 | |
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36 | <p> |
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37 | Hierarchies of volumes based on <i>CSG</i> or <i>specific</i> solids can be |
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38 | reflected by means of the <tt>G4ReflectionFactory</tt> class and |
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39 | <tt>G4ReflectedSolid</tt>, which implements a solid that has been shifted |
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40 | from its original reference frame to a new 'reflected' one. The reflection |
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41 | transformation is applied as a decomposition into rotation and translation |
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42 | transformations.<br> |
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43 | |
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44 | The factory is a singleton object which provides the following methods: |
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45 | <pre> |
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46 | G4PhysicalVolumesPair Place(const G4Transform3D& transform3D, |
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47 | const G4String& name, |
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48 | G4LogicalVolume* LV, |
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49 | G4LogicalVolume* motherLV, |
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50 | G4bool isMany, |
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51 | G4int copyNo, |
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52 | G4bool surfCheck=false) |
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53 | |
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54 | G4PhysicalVolumesPair Replicate(const G4String& name, |
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55 | G4LogicalVolume* LV, |
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56 | G4LogicalVolume* motherLV, |
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57 | EAxis axis, |
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58 | G4int nofReplicas, |
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59 | G4double width, |
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60 | G4double offset=0) |
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61 | |
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62 | G4PhysicalVolumesPair Divide(const G4String& name, |
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63 | G4LogicalVolume* LV, |
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64 | G4LogicalVolume* motherLV, |
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65 | EAxis axis, |
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66 | G4int nofDivisions, |
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67 | G4double width, |
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68 | G4double offset); |
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69 | </pre> |
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70 | |
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71 | The method <tt>Place()</tt> used for placements, evaluates the passed |
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72 | transformation. In case the transformation contains a reflection, the |
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73 | factory will act as follows: |
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74 | <ol> |
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75 | <li>Performs the transformation decomposition.</li> |
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76 | <li>Creates a new reflected solid and logical volume, or retrieves them |
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77 | from a map if the reflected object was already created.</li> |
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78 | <li>Transforms the daughters (if any) and place them in the given mother.</li> |
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79 | </ol> |
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80 | If successful, the result is a pair of physical volumes, where the second |
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81 | physical volume is a placement in a reflected mother. Optionally, it is also |
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82 | possible to force the overlaps check at the time of placement, by activating |
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83 | the <tt>surfCheck</tt> flag. |
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84 | <br> |
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85 | The method <tt>Replicate()</tt> creates replicas in the given mother. |
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86 | If successful, the result is a pair of physical volumes, where the second |
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87 | physical volume is a replica in a reflected mother. |
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88 | <br> |
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89 | The method <tt>Divide()</tt> creates divisions in the given mother. |
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90 | If successful, the result is a pair of physical volumes, where the second |
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91 | physical volume is a division in a reflected mother. There exists also two |
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92 | more variants of this method which may specify or not width or number of |
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93 | divisions. |
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94 | </p> |
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95 | <p> |
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96 | <b>Notes</b> |
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97 | <ul> |
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98 | <li>In order to reflect hierarchies containing divided volumes, |
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99 | it is necessary to explicitely instantiate a concrete <i>division</i> |
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100 | factory -before- applying the actual reflection: |
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101 | (i.e. - <TT>G4PVDivisionFactory::GetInstance();</TT>).</li> |
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102 | <li>Reflection of generic parameterised volumes is not possible yet.</li> |
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103 | </ul> |
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104 | </p> |
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105 | |
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106 | <p> |
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107 | <center> |
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108 | <table BORDER=1 CELLPADDING=8> |
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109 | <tr><td> |
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110 | <pre> |
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111 | #include "G4ReflectionFactory.hh" |
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112 | |
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113 | // Calor placement with rotation |
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114 | |
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115 | G4double calThickness = 100*cm; |
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116 | G4double Xpos = calThickness*1.5; |
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117 | G4RotationMatrix* rotD3 = new G4RotationMatrix(); |
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118 | rotD3->rotateY(10.*deg); |
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119 | |
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120 | G4VPhysicalVolume* physiCalor = |
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121 | new G4PVPlacement(rotD3, // rotation |
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122 | G4ThreeVector(Xpos,0.,0.), // at (Xpos,0,0) |
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123 | logicCalor, // its logical volume (defined elsewhere) |
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124 | "Calorimeter", // its name |
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125 | logicHall, // its mother volume (defined elsewhere) |
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126 | false, // no boolean operation |
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127 | 0); // copy number |
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128 | |
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129 | // Calor reflection with rotation |
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130 | // |
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131 | G4Translate3D translation(-Xpos, 0., 0.); |
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132 | G4Transform3D rotation = G4Rotate3D(*rotD3); |
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133 | G4ReflectX3D reflection; |
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134 | G4Transform3D transform = translation*rotation*reflection; |
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135 | |
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136 | G4ReflectionFactory::Instance() |
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137 | ->Place(transform, // the transformation with reflection |
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138 | "Calorimeter", // the actual name |
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139 | logicCalor, // the logical volume |
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140 | logicHall, // the mother volume |
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141 | false, // no boolean operation |
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142 | 1, // copy number |
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143 | false); // no overlap check triggered |
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144 | |
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145 | // Replicate layers |
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146 | // |
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147 | G4ReflectionFactory::Instance() |
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148 | ->Replicate("Layer", // layer name |
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149 | logicLayer, // layer logical volume (defined elsewhere) |
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150 | logicCalor, // its mother |
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151 | kXAxis, // axis of replication |
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152 | 5, // number of replica |
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153 | 20*cm); // width of replica |
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154 | </pre> |
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155 | </tr></td> |
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156 | |
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157 | <tr> |
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158 | <td ALIGN=center> |
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159 | Source listing 4.1.8<br> |
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160 | An example of usage of the <tt>G4ReflectionFactory</tt> class. |
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161 | </td> |
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162 | </tr> |
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163 | </table> |
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164 | </center> |
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165 | |
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166 | <hr><a href="../../../../Authors/html/subjectsToAuthors.html"> |
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167 | <i>About the authors</a></i> </P> |
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168 | |
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169 | </body> |
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170 | </html> |
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