Fix DAWN view for barrel calorimeter support

compact/ecal_barrel_interlayers.xml

 <lccdd>
 
     <display>
-    <vis name="EcalBarrelEnvelope_vis" alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
-    <vis name="EcalBarrelStave_vis"    alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelEnvelope_vis"   alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelStave_vis"      alpha="0.9" r="0.99" g="0.5" b="0" showDaughters="true" visible="false" />
+    <vis name="EcalBarrelFiberLayer_vis" alpha="0.9" r="0.1" g="0.5" b="0.5" showDaughters="false" visible="true" />
     </display>
   <define>
     <comment>
@@ -85,7 +86,6 @@
       <dimensions numsides="EcalBarrel_ModRepeat"
         rmin="EcalBarrel_rmin"
         z="EcalBarrel_length"/>
-      <staves vis="EcalBarrelStave_vis"/>
       <layer repeat="EcalBarrelImagingLayers_num" vis="AnlBlue"
         space_between="EcalBarrel_ScFiLayerThickness + EcalBarrel_SpaceBetween"
         space_before="0.*cm">
@@ -115,18 +115,16 @@
         rmin="EcalBarrel_rmin"
         z="EcalBarrel_length"/>
       <staves vis="EcalBarrelStave_vis">
-        <support inside="true"  material="Steel235" vis="AnlOrange"
-          thickness="EcalBarrel_Support_thickness"
-          n_beams="3" grid_size="25.0*cm" >
+        <support material="Steel235" vis="AnlOrange" n_beams="3" grid_size="25.0*cm"
+          thickness="EcalBarrel_Support_thickness" beam_thickness="EcalBarrel_Support_thickness/4" >
         </support>
       </staves>
       <layer repeat="EcalBarrelImagingLayers_num-1" vis="AnlBlue"
        space_between="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween"
        space_before="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween/2.">
-        <slice material="Lead" thickness="EcalBarrel_RadiatorThickness" vis="EcalBarrelFibersVis">
+        <slice material="Lead" thickness="EcalBarrel_RadiatorThickness" vis="EcalBarrelFiberLayer_vis">
           <fiber material="PlasticScint"
             sensitive="yes"
-            vis="EcalBarrelFiberVis"
             radius="EcalBarrel_FiberRadius"
             spacing_x="EcalBarrel_FiberXSpacing"
             spacing_z="EcalBarrel_FiberZSpacing"/>
@@ -138,14 +136,12 @@
           space_before="EcalBarrel_ImagingLayerThickness + EcalBarrel_SpaceBetween">
         <slice material="Lead"
           thickness="EcalBarrel_FiberLayerThickness/EcalBarrel_FiberChunkLayers_num"
-          vis="EcalBarrelFiberLayerVis">
+          vis="EcalBarrelFiberLayer_vis">
           <fiber material="PlasticScint"
             sensitive="yes"
-            vis="EcalBarrelFiberVis"
             radius="EcalBarrel_FiberRadius"
             spacing_x="EcalBarrel_FiberXSpacing"
-            spacing_z="EcalBarrel_FiberZSpacing">
-          </fiber>
+            spacing_z="EcalBarrel_FiberZSpacing"/>
         </slice>
       </layer>
     </detector>

src/BarrelCalorimeterInterlayers_geo.cpp

@@ -3,9 +3,13 @@
 // Assembly is used as the envelope so two different detectors can be interlayered with each other
 //
 //
-// Implementation of the Sci Fiber geometry: M. Żurek 06/19/2021
-// Support interlayers between multiple detectors: C. Peng 07/09/2021
-
+// 06/19/2021: Implementation of the Sci Fiber geometry. M. Żurek
+// 07/09/2021: Support interlayers between multiple detectors. C. Peng
+// 07/23/2021: Add assemblies as mother volumes of fibers to reduce the number of daughter volumes. C. Peng, M. Żurek
+//     Reference: TGeo performance issue with large number of daughter volumes
+//     https://indico.cern.ch/event/967418/contributions/4075358/attachments/2128099/3583278/201009_shKo_dd4hep.pdf
+// 07/24/2021: Changed support implementation to avoid too many uses of boolean geometries. DAWN view seems to have
+//     issue dealing with it. C. Peng
 
 #include "DD4hep/DetFactoryHelper.h"
 #include "XML/Layering.h"
@@ -17,13 +21,17 @@ using namespace dd4hep;
 using namespace dd4hep::detail;
 
 typedef ROOT::Math::XYPoint Point;
-// headers for helper functions, defined in BarrelCalorimeterHybrid_geo
+// fiber placement helpers, defined in BarrelCalorimeterHybrid_geo
 vector<vector<Point>> fiberPositions(double radius, double x_spacing, double z_spacing,
                                      double x, double z, double phi, double spacing_tol = 1e-2);
 std::pair<int, int> getNdivisions(double x, double z, double dx, double dz);
 vector<tuple<int, Point, Point, Point, Point>> gridPoints(int div_x, int div_z, double x, double z, double phi);
-void buildFibers(Detector& desc, SensitiveDetector sens, Volume &s_vol, xml_comp_t x_fiber,
-                 std::tuple<double, double, double, double> dimensions);
+
+// geometry helpers
+void buildFibers(Detector& desc, SensitiveDetector &sens, Volume &mother, xml_comp_t x_fiber,
+                 const std::tuple<double, double, double, double> &dimensions);
+void buildSupport(Detector& desc, Volume &mother, xml_comp_t x_support,
+                  const std::tuple<double, double, double, double> &dimensions);
 
 
 // barrel ecal layers contained in an assembly
@@ -33,7 +41,6 @@ static Ref_t create_detector(Detector& desc, xml_h e, SensitiveDetector sens)  {
   Material      air       = desc.air();
   int           det_id    = x_det.id();
   string        det_name  = x_det.nameStr();
-  xml_comp_t    x_staves  = x_det.staves();
   double        offset    = x_det.attr<double>(_Unicode(offset));
   xml_comp_t    x_dim     = x_det.dimensions();
   int           nsides    = x_dim.numsides();
@@ -150,75 +157,22 @@ static Ref_t create_detector(Detector& desc, xml_h e, SensitiveDetector sens)  {
     sdet.add(sd);
   }
 
-  Solid  support_frame_s;
   // optional stave support
-  if (x_staves.hasChild("support")) {
-    xml_comp_t  x_support           = x_staves.child(_U(support));
-    double      support_thickness   = getAttrOrDefault(x_support, _U(thickness), 5.0 * cm);
-    double      trd_x1_support      = (2 * std::tan(hphi) * l_pos_z + support_thickness)/2;
-    // is the support on the inside surface?
-    bool        is_inside_support   = getAttrOrDefault<bool>(x_support, _Unicode(inside), true);
-    double      trd_x1              = std::tan(hphi) * inner_r;
-    double      trd_x2              = std::tan(hphi) * (l_pos_z + support_thickness);
-    double      trd_y1              = x_dim.z()/2.;
-
-    // number of "beams" running the length of the stave.
-    int    n_beams          = getAttrOrDefault<int>(x_support, _Unicode(n_beams), 3);
-    double beam_thickness   = support_thickness / 4.0; // maybe a parameter later...
-    trd_x1_support          = (2 * std::tan(hphi) * (l_pos_z + beam_thickness)) / 2.;
-    double grid_size        = getAttrOrDefault(x_support, _Unicode(grid_size), 25.0 * cm);
-    double beam_width       = 2.0 * trd_x1_support / (n_beams + 1); // quick hack to make some gap between T beams
-
-    double cross_beam_thickness = support_thickness/4.0;
-    //double trd_x1_support     = (2 * std::tan(hphi) * (inner_r + beam_thickness)) / 2.;
-    double trd_x2_support       = trd_x2;
-
-    int n_cross_supports = std::floor((trd_y1-cross_beam_thickness)/grid_size);
-
-    Box        beam_vert_s(beam_thickness / 2.0 , trd_y1, support_thickness / 2.0 );
-    Box        beam_hori_s(beam_width / 2.0, trd_y1, beam_thickness / 2.0);
-    UnionSolid T_beam_s(beam_vert_s, beam_hori_s, Position(0, 0, -support_thickness / 2.0 + beam_thickness / 2.0));
-
-    // cross supports
-    Trapezoid  trd_support(trd_x1_support,trd_x2_support,
-                           beam_thickness / 2.0, beam_thickness / 2.0,
-                           support_thickness / 2.0 - cross_beam_thickness/2.0);
-    UnionSolid support_array_start_s(T_beam_s,trd_support,Position(0,0,cross_beam_thickness/2.0));
-    for (int isup = 0; isup < n_cross_supports; isup++) {
-      support_array_start_s = UnionSolid(support_array_start_s, trd_support,
-                                         Position(0, -1.0 * isup * grid_size, cross_beam_thickness/2.0));
-      support_array_start_s = UnionSolid(support_array_start_s, trd_support,
-                                         Position(0, 1.0 * isup * grid_size, cross_beam_thickness/2.0));
+  if (x_det.hasChild(_U(staves))) {
+    xml_comp_t x_staves = x_det.staves();
+    mod_vol.setVisAttributes(desc.visAttributes(x_staves.visStr()));
+    if (x_staves.hasChild(_U(support))) {
+      buildSupport(desc, mod_vol, x_staves.child(_U(support)), {inner_r, l_pos_z, x_dim.z(), hphi});
     }
-    support_array_start_s =
-        UnionSolid(support_array_start_s, beam_hori_s,
-                   Position(-1.8 * 0.5*(trd_x1+trd_x2_support) / n_beams, 0, -support_thickness / 2.0 + beam_thickness / 2.0));
-    support_array_start_s =
-        UnionSolid(support_array_start_s, beam_hori_s,
-                   Position(1.8 * 0.5*(trd_x1+trd_x2_support) / n_beams, 0, -support_thickness / 2.0 + beam_thickness / 2.0));
-    support_array_start_s =
-        UnionSolid(support_array_start_s, beam_vert_s, Position(-1.8 * 0.5*(trd_x1+trd_x2_support) / n_beams, 0, 0));
-    support_array_start_s =
-        UnionSolid(support_array_start_s, beam_vert_s, Position(1.8 * 0.5*(trd_x1+trd_x2_support) / n_beams, 0, 0));
-
-    support_frame_s = support_array_start_s;
-
-    Material support_mat = desc.material(x_support.materialStr());
-    Volume   support_vol("support_frame_v", support_frame_s, support_mat);
-    support_vol.setVisAttributes(desc,x_support.visStr());
-
-    // figure out how to best place
-    auto pv = mod_vol.placeVolume(support_vol, Position(0.0, 0.0, l_pos_z + support_thickness / 2.0));
   }
 
-  //l_pos_z += support_thickness;
   // Set envelope volume attributes.
   envelope.setAttributes(desc, x_det.regionStr(), x_det.limitsStr(), x_det.visStr());
   return sdet;
 }
 
-void buildFibers(Detector& desc, SensitiveDetector sens, Volume &s_vol, xml_comp_t x_fiber,
-                 std::tuple<double, double, double, double> dimensions)
+void buildFibers(Detector& desc, SensitiveDetector &sens, Volume &s_vol, xml_comp_t x_fiber,
+                 const std::tuple<double, double, double, double> &dimensions)
 {
   auto [s_trd_x1, s_thick, s_length, hphi] = dimensions;
   double f_radius = getAttrOrDefault(x_fiber, _U(radius), 0.1 * cm);
@@ -258,7 +212,7 @@ void buildFibers(Detector& desc, SensitiveDetector sens, Volume &s_vol, xml_comp
       // Check to which grid fiber belongs to
       for (auto &poly_vtx : grid_vtx) {
         if (p.y() != l_pos_y) {
-          std::cerr << Form("Expected the same y position from a same line: %.2f, but got %.f", l_pos_y, p.y())
+          std::cerr << Form("Expected the same y position from a same line: %.2f, but got %.2f", l_pos_y, p.y())
                     << std::endl;
           continue;
         }
@@ -289,11 +243,96 @@ void buildFibers(Detector& desc, SensitiveDetector sens, Volume &s_vol, xml_comp
       PlacedVolume fiber_phv = lfibers.placeVolume(f_vol, Position(p.x(), 0., 0.));
       fiber_phv.addPhysVolID(f_id_grid, f_grid_id + 1).addPhysVolID(f_id_fiber, f_id + 1);
     }
+    lfibers.ptr()->Voxelize("");
     Transform3D l_tr(RotationZYX(0,0,M_PI*0.5),Position(0., 0, l_pos_y));
     s_vol.placeVolume(lfibers, l_tr);
   }
 }
 
+// DAWN view seems to have some issue with overlapping solids even if they were unions
+// The support is now built without overlapping
+void buildSupport(Detector& desc, Volume &mod_vol, xml_comp_t x_support,
+                  const std::tuple<double, double, double, double> &dimensions)
+{
+  auto [inner_r, l_pos_z, stave_length, hphi] = dimensions;
+
+  double support_thickness = getAttrOrDefault(x_support, _Unicode(thickness), 5. * cm);
+  double beam_thickness    = getAttrOrDefault(x_support, _Unicode(beam_thickness), support_thickness/4.);
+  // sanity check
+  if (beam_thickness > support_thickness/3.) {
+    std::cerr << Form("beam_thickness (%.2f) cannot be greater than support_thickness/3 (%.2f), shrink it to fit",
+                      beam_thickness, support_thickness/3.) << std::endl;
+    beam_thickness = support_thickness/3.;
+  }
+  double   trd_x1_support = std::tan(hphi) * l_pos_z;
+  double   trd_x2_support = std::tan(hphi) * (l_pos_z + support_thickness);
+  double   trd_y          = stave_length / 2.;
+  Assembly env_vol        ("support_envelope");
+
+  double grid_size        = getAttrOrDefault(x_support, _Unicode(grid_size), 25. * cm);
+  int    n_cross_supports = std::floor(trd_y - beam_thickness)/grid_size;
+  // number of "beams" running the length of the stave.
+  // @TODO make it configurable
+  int    n_beams          = getAttrOrDefault(x_support, _Unicode(n_beams), 3);;
+  double beam_width       = 2. * trd_x1_support / (n_beams + 1); // quick hack to make some gap between T beams
+  double beam_gap         = getAttrOrDefault(x_support, _Unicode(beam_gap), 3.*cm);
+
+  // build H-shape beam
+  double beam_space_x    = beam_width + beam_gap;
+  double beam_space_z    = support_thickness - beam_thickness;
+  double cross_thickness = support_thickness - 2.*beam_thickness;
+  double beam_pos_z      = -beam_thickness / 2.;
+  double beam_center_z   = support_thickness / 2. + beam_pos_z;
+
+  Box        beam_vert_s(beam_thickness / 2. , trd_y, cross_thickness / 2.);
+  Box        beam_hori_s(beam_width / 2., trd_y, beam_thickness / 2.);
+  UnionSolid T_beam_s(beam_hori_s, beam_vert_s, Position(0., 0., beam_space_z / 2.));
+  UnionSolid H_beam_s(T_beam_s, beam_hori_s, Position(0., 0., support_thickness - beam_thickness));
+  Volume H_beam_vol("H_beam", H_beam_s, desc.material(x_support.materialStr()));
+  H_beam_vol.setVisAttributes(desc, x_support.visStr());
+  // place H beams first
+  double beam_start_x = - (n_beams - 1) * (beam_width + beam_gap) / 2.;
+  for (int i = 0; i < n_beams; ++i) {
+    Position beam_pos(beam_start_x + i * (beam_width + beam_gap), 0., - support_thickness / 2. - beam_pos_z);
+    env_vol.placeVolume(H_beam_vol, beam_pos);
+  }
+
+  // place central crossing beams that connects the H beams
+  double cross_x = beam_space_x - beam_thickness;
+  Box cross_s(cross_x / 2., beam_thickness / 2., cross_thickness / 2.);
+  Volume cross_vol("cross_center_beam", cross_s, desc.material(x_support.materialStr()));
+  cross_vol.setVisAttributes(desc, x_support.visStr());
+  for (int i = 0; i < n_beams - 1; ++i) {
+    env_vol.placeVolume(cross_vol, Position(beam_start_x + beam_space_x * (i + 0.5), 0., 0.));
+    for (int j = 1; j < n_cross_supports; j++) {
+      env_vol.placeVolume(cross_vol, Position(beam_start_x + beam_space_x * (i + 0.5), -j * grid_size, 0.));
+      env_vol.placeVolume(cross_vol, Position(beam_start_x + beam_space_x * (i + 0.5), j * grid_size, 0.));
+    }
+  }
+
+  // place edge crossing beams that connects the neighbour support
+  // @TODO: connection part is still using boolean volumes, maybe problematic to DAWN
+  double    cross_edge_x = trd_x1_support + beam_start_x - beam_thickness / 2.;
+  double    cross_trd_x1 = cross_edge_x + std::tan(hphi) * beam_thickness;
+  double    cross_trd_x2 = cross_trd_x1 + 2.* std::tan(hphi) * cross_thickness;
+  double    edge_pos_x   = beam_start_x - beam_thickness / 2. - cross_trd_x1 / 2.;
+  Trapezoid cross_s2_trd (cross_trd_x1 / 2., cross_trd_x2 / 2.,
+                          beam_thickness / 2., beam_thickness / 2., cross_thickness / 2.);
+  Box       cross_s2_box ((cross_trd_x2 - cross_trd_x1)/2., beam_thickness / 2., cross_thickness / 2.);
+  SubtractionSolid cross_s2(cross_s2_trd, cross_s2_box, Position((cross_trd_x1 + cross_trd_x2) / 4., 0., 0.));
+  Volume cross_vol2("cross_edge_beam", cross_s2, desc.material(x_support.materialStr()));
+  cross_vol2.setVisAttributes(desc, x_support.visStr());
+  env_vol.placeVolume(cross_vol2, Position(edge_pos_x, 0., 0.));
+  env_vol.placeVolume(cross_vol2, Transform3D(Translation3D(-edge_pos_x, 0., 0.) * RotationZ(M_PI)));
+  for (int j = 1; j < n_cross_supports; j++) {
+    env_vol.placeVolume(cross_vol2, Position(edge_pos_x, -j * grid_size, 0.));
+    env_vol.placeVolume(cross_vol2, Position(edge_pos_x, j * grid_size, 0.));
+    env_vol.placeVolume(cross_vol2, Transform3D(Translation3D(-edge_pos_x, -j * grid_size, 0.) * RotationZ(M_PI)));
+    env_vol.placeVolume(cross_vol2, Transform3D(Translation3D(-edge_pos_x, j * grid_size, 0.) * RotationZ(M_PI)));
+  }
+
+  mod_vol.placeVolume(env_vol, Position(0.0, 0.0, l_pos_z + support_thickness/2.));
+}
+
 DECLARE_DETELEMENT(athena_EcalBarrelInterlayers, create_detector)
-// DECLARE_DETELEMENT(athena_EcalBarrelInterlayers, create_detector)