1 | <!-- ******************************************************** --> |
---|
2 | <!-- --> |
---|
3 | <!-- [History] --> |
---|
4 | <!-- Converted to DocBook: Katsuya Amako, Aug-2006 --> |
---|
5 | <!-- Changed by: Gabriele Cosmo, 18-Apr-2005 --> |
---|
6 | <!-- --> |
---|
7 | <!-- ******************************************************** --> |
---|
8 | |
---|
9 | |
---|
10 | <!-- ******************* Section (Level#2) ****************** --> |
---|
11 | <sect2 id="sect.Geom.Reflec"> |
---|
12 | <title> |
---|
13 | Reflecting Hierarchies of Volumes |
---|
14 | </title> |
---|
15 | |
---|
16 | <para> |
---|
17 | Hierarchies of volumes based on <emphasis>CSG</emphasis> or |
---|
18 | <emphasis>specific</emphasis> solids can be reflected by means of the |
---|
19 | <literal>G4ReflectionFactory</literal> class and <literal>G4ReflectedSolid</literal>, |
---|
20 | which implements a solid that has been shifted from its original |
---|
21 | reference frame to a new 'reflected' one. The reflection |
---|
22 | transformation is applied as a decomposition into rotation and |
---|
23 | translation transformations. |
---|
24 | </para> |
---|
25 | |
---|
26 | <para> |
---|
27 | The factory is a singleton object which provides the following |
---|
28 | methods: |
---|
29 | |
---|
30 | <informalexample> |
---|
31 | <programlisting> |
---|
32 | G4PhysicalVolumesPair Place(const G4Transform3D& transform3D, |
---|
33 | const G4String& name, |
---|
34 | G4LogicalVolume* LV, |
---|
35 | G4LogicalVolume* motherLV, |
---|
36 | G4bool isMany, |
---|
37 | G4int copyNo, |
---|
38 | G4bool surfCheck=false) |
---|
39 | |
---|
40 | G4PhysicalVolumesPair Replicate(const G4String& name, |
---|
41 | G4LogicalVolume* LV, |
---|
42 | G4LogicalVolume* motherLV, |
---|
43 | EAxis axis, |
---|
44 | G4int nofReplicas, |
---|
45 | G4double width, |
---|
46 | G4double offset=0) |
---|
47 | |
---|
48 | G4PhysicalVolumesPair Divide(const G4String& name, |
---|
49 | G4LogicalVolume* LV, |
---|
50 | G4LogicalVolume* motherLV, |
---|
51 | EAxis axis, |
---|
52 | G4int nofDivisions, |
---|
53 | G4double width, |
---|
54 | G4double offset); |
---|
55 | </programlisting> |
---|
56 | </informalexample> |
---|
57 | </para> |
---|
58 | |
---|
59 | <para> |
---|
60 | The method <literal>Place()</literal> used for placements, evaluates the |
---|
61 | passed transformation. In case the transformation contains a |
---|
62 | reflection, the factory will act as follows: |
---|
63 | |
---|
64 | <orderedlist spacing="compact"> |
---|
65 | <listitem><para> |
---|
66 | Performs the transformation decomposition. |
---|
67 | </para></listitem> |
---|
68 | <listitem><para> |
---|
69 | Creates a new reflected solid and logical volume, or retrieves |
---|
70 | them from a map if the reflected object was already created. |
---|
71 | </para></listitem> |
---|
72 | <listitem><para> |
---|
73 | Transforms the daughters (if any) and place them in the given mother. |
---|
74 | </para></listitem> |
---|
75 | </orderedlist> |
---|
76 | </para> |
---|
77 | |
---|
78 | <para> |
---|
79 | If successful, the result is a pair of physical volumes, where the |
---|
80 | second physical volume is a placement in a reflected mother. |
---|
81 | Optionally, it is also possible to force the overlaps check at the |
---|
82 | time of placement, by activating the <literal>surfCheck</literal> flag. |
---|
83 | </para> |
---|
84 | |
---|
85 | <para> |
---|
86 | The method <literal>Replicate()</literal> creates replicas in the given |
---|
87 | mother. If successful, the result is a pair of physical volumes, |
---|
88 | where the second physical volume is a replica in a reflected |
---|
89 | mother. |
---|
90 | </para> |
---|
91 | |
---|
92 | <para> |
---|
93 | The method <literal>Divide()</literal> creates divisions in the given mother. |
---|
94 | If successful, the result is a pair of physical volumes, where the |
---|
95 | second physical volume is a division in a reflected mother. There |
---|
96 | exists also two more variants of this method which may specify or |
---|
97 | not width or number of divisions. |
---|
98 | </para> |
---|
99 | |
---|
100 | <note> |
---|
101 | <title> |
---|
102 | Notes |
---|
103 | </title> |
---|
104 | <para> |
---|
105 | <itemizedlist spacing="compact"> |
---|
106 | <listitem><para> |
---|
107 | In order to reflect hierarchies containing divided volumes, it |
---|
108 | is necessary to explicitely instantiate a concrete <emphasis>division</emphasis> |
---|
109 | factory -before- applying the actual reflection: (i.e. - |
---|
110 | <literal>G4PVDivisionFactory::GetInstance();</literal>). |
---|
111 | </para></listitem> |
---|
112 | <listitem><para> |
---|
113 | Reflection of generic parameterised volumes is not possible yet. |
---|
114 | </para></listitem> |
---|
115 | </itemizedlist> |
---|
116 | </para> |
---|
117 | </note> |
---|
118 | |
---|
119 | <example id="programlist_Geom.Reflec_1"> |
---|
120 | <title> |
---|
121 | An example of usage of the |
---|
122 | <literal>G4ReflectionFactory</literal> class.</title> |
---|
123 | <programlisting> |
---|
124 | #include "G4ReflectionFactory.hh" |
---|
125 | |
---|
126 | // Calor placement with rotation |
---|
127 | |
---|
128 | G4double calThickness = 100*cm; |
---|
129 | G4double Xpos = calThickness*1.5; |
---|
130 | G4RotationMatrix* rotD3 = new G4RotationMatrix(); |
---|
131 | rotD3->rotateY(10.*deg); |
---|
132 | |
---|
133 | G4VPhysicalVolume* physiCalor = |
---|
134 | new G4PVPlacement(rotD3, // rotation |
---|
135 | G4ThreeVector(Xpos,0.,0.), // at (Xpos,0,0) |
---|
136 | logicCalor, // its logical volume (defined elsewhere) |
---|
137 | "Calorimeter", // its name |
---|
138 | logicHall, // its mother volume (defined elsewhere) |
---|
139 | false, // no boolean operation |
---|
140 | 0); // copy number |
---|
141 | |
---|
142 | // Calor reflection with rotation |
---|
143 | // |
---|
144 | G4Translate3D translation(-Xpos, 0., 0.); |
---|
145 | G4Transform3D rotation = G4Rotate3D(*rotD3); |
---|
146 | G4ReflectX3D reflection; |
---|
147 | G4Transform3D transform = translation*rotation*reflection; |
---|
148 | |
---|
149 | G4ReflectionFactory::Instance() |
---|
150 | ->Place(transform, // the transformation with reflection |
---|
151 | "Calorimeter", // the actual name |
---|
152 | logicCalor, // the logical volume |
---|
153 | logicHall, // the mother volume |
---|
154 | false, // no boolean operation |
---|
155 | 1, // copy number |
---|
156 | false); // no overlap check triggered |
---|
157 | |
---|
158 | // Replicate layers |
---|
159 | // |
---|
160 | G4ReflectionFactory::Instance() |
---|
161 | ->Replicate("Layer", // layer name |
---|
162 | logicLayer, // layer logical volume (defined elsewhere) |
---|
163 | logicCalor, // its mother |
---|
164 | kXAxis, // axis of replication |
---|
165 | 5, // number of replica |
---|
166 | 20*cm); // width of replica |
---|
167 | </programlisting> |
---|
168 | </example> |
---|
169 | |
---|
170 | </sect2> |
---|