diff --git a/include/xdg/geometry_data.h b/include/xdg/geometry_data.h
index f3b69c7..11b4048 100644
--- a/include/xdg/geometry_data.h
+++ b/include/xdg/geometry_data.h
@@ -1,6 +1,8 @@
 #ifndef _XDG_GEOMETRY_DATA_H
 #define _XDG_GEOMETRY_DATA_H
 
+#include "xdg/constants.h"
+
 namespace xdg
 {
 
@@ -8,6 +10,7 @@ struct MeshManager; // Forward declaration
 struct TriangleRef; // Forward declaration
 
 struct GeometryUserData {
+  MeshID surface_id {ID_NONE}; //! ID of the surface this geometry data is associated with
   MeshManager* mesh_manager {nullptr}; //! Pointer to the mesh manager for this geometry
   TriangleRef* tri_ref_buffer {nullptr}; //! Pointer to the triangles in the geometry
   double box_bump; //! Bump distance for the bounding boxes in this geometry
diff --git a/include/xdg/ray_tracing_interface.h b/include/xdg/ray_tracing_interface.h
index 03c5152..c6632b9 100644
--- a/include/xdg/ray_tracing_interface.h
+++ b/include/xdg/ray_tracing_interface.h
@@ -14,6 +14,8 @@
 namespace xdg
 {
 
+using TreeID = RTCScene;
+
 class RayTracer {
 // Constructors
 public:
diff --git a/include/xdg/triangle_ref.h b/include/xdg/triangle_ref.h
index adb6798..0f84302 100644
--- a/include/xdg/triangle_ref.h
+++ b/include/xdg/triangle_ref.h
@@ -12,7 +12,6 @@ struct TriangleRef; // Forward declaration
 // TODO: could be a more generic primitive ref?
 struct TriangleRef {
   MeshID triangle_id {ID_NONE};
-  MeshID surface_id {ID_NONE};
   Sense sense {Sense::UNSET};
 };
 
diff --git a/src/ray_tracing_interface.cpp b/src/ray_tracing_interface.cpp
index 7bbcf76..0e9a487 100644
--- a/src/ray_tracing_interface.cpp
+++ b/src/ray_tracing_interface.cpp
@@ -51,7 +51,6 @@ RayTracer::register_volume(const std::shared_ptr<MeshManager> mesh_manager,
     for (int i = 0; i < surface_elements.size(); ++i) {
       auto& triangle_ref = triangle_storage[i + storage_offset];
       triangle_ref.triangle_id = surface_elements[i];
-      triangle_ref.surface_id = surface_id;
       triangle_ref.sense = triangle_sense;
     }
     storage_offset += surface_elements.size();
@@ -86,6 +85,7 @@ RayTracer::register_volume(const std::shared_ptr<MeshManager> mesh_manager,
     this->surface_to_geometry_map_[surface] = surface_geometry;
 
     GeometryUserData surface_data;
+    surface_data.surface_id = surface;
     surface_data.mesh_manager = mesh_manager.get();
     surface_data.tri_ref_buffer = tri_ref_ptr + buffer_start;
     user_data_map_[surface_geometry] = surface_data;
@@ -255,9 +255,10 @@ Direction RayTracer::get_normal(MeshID surface,
     TriangleRef triangle_ref;
     closest(surface_vols.first, point, dist, triangle_ref);
 
-    if (triangle_ref.surface_id != surface) {
-      fatal_error("Point {} was closest to surface {}, not surface {}, in volume {}.", point, triangle_ref.surface_id, surface, surface_vols.first);
-    }
+    // TODO: bring this back when we have a better way to handle this
+    // if (geom_data.surface_id != surface) {
+    //   fatal_error("Point {} was closest to surface {}, not surface {}, in volume {}.", point, geom_data.surface_id, surface, surface_vols.first);
+    // }
     element = triangle_ref.triangle_id;
   }