fix: detray json writing fixes

Plugins/Json/include/Acts/Plugins/Json/DetectorVolumeFinderJsonConverter.hpp

@@ -43,7 +43,7 @@ void convert(nlohmann::json& jIndexedVolumes,
   auto castedDelegate = dynamic_cast<const DelegateType*>(instance);
   if (castedDelegate != nullptr) {
     jIndexedVolumes = IndexedGridJsonHelper::convertImpl<DelegateType>(
-        *castedDelegate, detray);
+        *castedDelegate, detray, false);
     if (detray) {
       jIndexedVolumes["volume_link"] = 1;
       nlohmann::json jAccLink;

Plugins/Json/include/Acts/Plugins/Json/GridJsonConverter.hpp

@@ -84,10 +84,14 @@ nlohmann::json toJson(const grid_type& grid) {
 ///
 /// @tparam grid_type the type of the grid
 /// @param grid the grid object
+/// @param swapAxis - this is needed for detray
+///
+/// @note detray has a different offset for the
+/// local indices, it starts at 0
 ///
 /// @return a json object to represent the grid
 template <typename grid_type>
-nlohmann::json toJsonDetray(const grid_type& grid) {
+nlohmann::json toJsonDetray(const grid_type& grid, bool swapAxis = false) {
   nlohmann::json jGrid;
 
   auto axes = grid.axes();
@@ -106,7 +110,7 @@ nlohmann::json toJsonDetray(const grid_type& grid) {
   if constexpr (grid_type::DIM == 1u) {
     for (unsigned int ib0 = 1u; ib0 <= axes[0u]->getNBins(); ++ib0) {
       typename grid_type::index_t lbin;
-      lbin[0u] = ib0;
+      lbin[0u] = ib0 - 1u;
       nlohmann::json jBin;
       jBin["loc_index"] = lbin;
       jBin["content"] = grid.atLocalBins(lbin);
@@ -116,11 +120,13 @@ nlohmann::json toJsonDetray(const grid_type& grid) {
 
   // 2D connections
   if constexpr (grid_type::DIM == 2u) {
-    for (unsigned int ib0 = 1u; ib0 <= axes[0u]->getNBins(); ++ib0) {
-      for (unsigned int ib1 = 1u; ib1 <= axes[1u]->getNBins(); ++ib1) {
+    unsigned int iaxis0 = swapAxis ? 1u : 0u;
+    unsigned int iaxis1 = swapAxis ? 0u : 1u;
+    for (unsigned int ib0 = 1u; ib0 <= axes[iaxis0]->getNBins(); ++ib0) {
+      for (unsigned int ib1 = 1u; ib1 <= axes[iaxis1]->getNBins(); ++ib1) {
         typename grid_type::index_t lbin;
-        lbin[0u] = ib0;
-        lbin[1u] = ib1;
+        lbin[0u] = ib0 - 1u;
+        lbin[1u] = ib1 - 1u;
         nlohmann::json jBin;
         jBin["loc_index"] = lbin;
         jBin["content"] = grid.atLocalBins(lbin);

Plugins/Json/include/Acts/Plugins/Json/IndexedGridJsonHelper.hpp

@@ -22,10 +22,18 @@ using namespace Experimental::detail::GridAxisGenerators;
 namespace IndexedGridJsonHelper {
 
 /// @brief The actual conversion method
+///
+/// @param indexGrid is the index grid to be written
+/// @param detray is a flag indicating detray writout
+/// @param checkSwap is a flag indicating if the axes should be swapped
 template <typename index_grid>
-nlohmann::json convertImpl(const index_grid& indexGrid, bool detray = false) {
+nlohmann::json convertImpl(const index_grid& indexGrid, bool detray = false,
+                           bool checkSwap = false) {
   nlohmann::json jIndexedGrid;
 
+  // Axis swapping
+  bool swapAxes = checkSwap;
+
   // Fill the casts
   nlohmann::json jCasts;
   // 1D casts
@@ -36,12 +44,14 @@ nlohmann::json convertImpl(const index_grid& indexGrid, bool detray = false) {
   if constexpr (index_grid::grid_type::DIM == 2u) {
     jCasts.push_back(indexGrid.casts[0u]);
     jCasts.push_back(indexGrid.casts[1u]);
+    swapAxes = checkSwap &&
+               (indexGrid.casts[0u] == binZ && indexGrid.casts[1u] == binPhi);
   }
   jIndexedGrid["casts"] = jCasts;
   jIndexedGrid["transform"] =
       Transform3JsonConverter::toJson(indexGrid.transform);
   if (detray) {
-    jIndexedGrid = GridJsonConverter::toJsonDetray(indexGrid.grid);
+    jIndexedGrid = GridJsonConverter::toJsonDetray(indexGrid.grid, swapAxes);
   } else {
     jIndexedGrid["grid"] = GridJsonConverter::toJson(indexGrid.grid);
   }

Plugins/Json/src/DetectorJsonConverter.cpp

@@ -149,6 +149,23 @@ nlohmann::json Acts::DetectorJsonConverter::toJsonDetray(
     if (jSurfacesDelegate.is_null()) {
       continue;
     }
+    // Patch axes for cylindrical grid surfaces, axes are swapped
+    // at this point
+    auto jAccLink = jSurfacesDelegate["acc_link"];
+    std::size_t accLinkType = jAccLink["type"];
+    if (accLinkType == 4u) {
+      // Radial value to transfer phi to rphi
+      std::vector<ActsScalar> bValues = volume->volumeBounds().values();
+      ActsScalar rRef = 0.5 * (bValues[1] + bValues[0]);
+      // Get the axes
+      auto& jAxes = jSurfacesDelegate["axes"];
+      // r*phi axis is the first one
+      std::vector<ActsScalar> jAxesEdges = jAxes[0u]["edges"];
+      std::for_each(jAxesEdges.begin(), jAxesEdges.end(),
+                    [rRef](ActsScalar& phi) { phi *= rRef; });
+      // Write back the patches axis edges
+      jSurfacesDelegate["axes"][0u]["edges"] = jAxesEdges;
+    }
     // Colplete the grid json for detray usage
     jSurfacesDelegate["volume_link"] = iv;
     // jSurfacesDelegate["acc_link"] =

Plugins/Json/src/PortalJsonConverter.cpp

@@ -22,6 +22,7 @@
 #include "Acts/Surfaces/RegularSurface.hpp"
 #include "Acts/Surfaces/Surface.hpp"
 #include "Acts/Utilities/Enumerate.hpp"
+#include "Acts/Utilities/VectorHelpers.hpp"
 
 #include <algorithm>
 #include <iterator>
@@ -134,11 +135,11 @@ std::vector<nlohmann::json> Acts::PortalJsonConverter::toJsonDetray(
       const auto& cast = multiLink1D->indexedUpdator.casts[0u];
       const auto& transform = multiLink1D->indexedUpdator.transform;
       const auto& volumes = multiLink1D->indexedUpdator.extractor.dVolumes;
-      if (!transform.isApprox(Transform3::Identity())) {
-        std::runtime_error(
-            "PortalJsonConverter: transformed boundary link implementation not "
-            "(yet) supported");
-      }
+
+      // Apply the correction from local to global boundaries
+      ActsScalar gCorr = VectorHelpers::cast(transform.translation(), cast);
+      std::for_each(boundaries.begin(), boundaries.end(),
+                    [&gCorr](ActsScalar& b) { b -= gCorr; });
 
       // Get the volume indices
       auto surfaceType = surfaceAdjusted->type();