diff --git a/include/xdg/constants.h b/include/xdg/constants.h
index 79007d2..51b044d 100644
--- a/include/xdg/constants.h
+++ b/include/xdg/constants.h
@@ -67,7 +67,7 @@ static Property VOID_MATERIAL {PropertyType::MATERIAL, "void"};
 enum class RayFireType { VOLUME, POINT_CONTAINMENT, ACCUMULATE_HITS, FIND_VOLUME };
 
 //
-enum class HitOrientation { NONE, EXITING, ENTERING };
+enum class HitOrientation { ANY, EXITING, ENTERING };
 
 } // namespace xdg
 
diff --git a/include/xdg/embree3.h b/include/xdg/embree3.h
index a847db6..9cf07a1 100644
--- a/include/xdg/embree3.h
+++ b/include/xdg/embree3.h
@@ -14,4 +14,12 @@ inline void rtcIntersect1(RTCScene scene, RTCRayHit* rayhit) {
   }
 }
 
+inline void rtcOccluded1(RTCScene scene, RTCRay* ray) {
+  {
+    RTCIntersectContext context;
+    rtcInitIntersectContext(&context);
+    rtcOccluded1(scene, &context, ray);
+  }
+}
+
 #endif // include guard
\ No newline at end of file
diff --git a/include/xdg/ray_tracing_interface.h b/include/xdg/ray_tracing_interface.h
index aa0e848..72e4eef 100644
--- a/include/xdg/ray_tracing_interface.h
+++ b/include/xdg/ray_tracing_interface.h
@@ -41,6 +41,11 @@ class RayTracer {
                const Position& origin,
                double& dist);
 
+  bool occluded(MeshID volume,
+                const Position& origin,
+                const Direction& direction,
+                double& dist) const;
+
 // Accessors
   int num_registered_volumes() const { return volume_map_.size(); }
 
diff --git a/src/ray_tracing_interface.cpp b/src/ray_tracing_interface.cpp
index 0e5a7b7..46d4d45 100644
--- a/src/ray_tracing_interface.cpp
+++ b/src/ray_tracing_interface.cpp
@@ -166,4 +166,30 @@ void RayTracer::closest(MeshID volume,
   distance = query.dradius;
 }
 
+bool RayTracer::occluded(MeshID volume,
+                         const Position& origin,
+                         const Direction& direction,
+                         double& distance) const
+{
+  RTCScene scene = volume_map_.at(volume);
+
+  RTCDRay ray;
+  ray.set_org(origin);
+  ray.set_dir(direction);
+  ray.set_tfar(INFTY);
+  ray.set_tnear(0.0);
+  ray.rf_type = RayFireType::FIND_VOLUME;
+  ray.orientation = HitOrientation::ANY;
+  ray.flags = 0;
+  ray.mask = -1; // no mask
+
+  // fire the ray
+  {
+    rtcOccluded1(scene, (RTCRay*)&ray);
+  }
+
+  distance = ray.dtfar;
+  return distance != INFTY;
+}
+
 } // namespace xdg
\ No newline at end of file
diff --git a/src/triangle_ref.cpp b/src/triangle_ref.cpp
index 8512a43..dcab7ee 100644
--- a/src/triangle_ref.cpp
+++ b/src/triangle_ref.cpp
@@ -96,23 +96,6 @@ void TriangleIntersectionFunc(RTCIntersectFunctionNArguments* args) {
   rayhit->hit.dNg[2] = normal[2];
 }
 
-
-void TriangleOcclusionFunc(RTCOccludedFunctionNArguments* args) {
-  const GeometryUserData* user_data = (const GeometryUserData*) args->geometryUserPtr;
-  const MeshManager* mesh_manager = user_data->mesh_manager;
-  const TriangleRef& tri_ref = user_data->tri_ref_buffer[args->primID];
-
-  auto vertices = mesh_manager->triangle_vertices(tri_ref.triangle_id);
-
-  // get the double precision ray from the args
-  RTCDRay* ray = (RTCDRay*) args->ray;
-
-  double plucker_dist;
-  if (plucker_ray_tri_intersect(vertices, ray->dorg, ray->ddir, plucker_dist)) {
-    ray->set_tfar(-INFTY);
-  }
-}
-
 bool TriangleClosestFunc(RTCPointQueryFunctionArguments* args) {
   RTCGeometry g = rtcGetGeometry(*(RTCScene*)args->userPtr, args->geomID);
   // get the array of DblTri's stored on the geometry
@@ -140,6 +123,22 @@ bool TriangleClosestFunc(RTCPointQueryFunctionArguments* args) {
   }
 }
 
+void TriangleOcclusionFunc(RTCOccludedFunctionNArguments* args) {
+  const GeometryUserData* user_data = (const GeometryUserData*) args->geometryUserPtr;
+  const MeshManager* mesh_manager = user_data->mesh_manager;
+  const TriangleRef& tri_ref = user_data->tri_ref_buffer[args->primID];
+
+  auto vertices = mesh_manager->triangle_vertices(tri_ref.triangle_id);
+
+  // get the double precision ray from the args
+  RTCDRay* ray = (RTCDRay*) args->ray;
+
+  double plucker_dist;
+  if (plucker_ray_tri_intersect(vertices, ray->dorg, ray->ddir, plucker_dist)) {
+    ray->set_tfar(-INFTY);
+  }
+}
+
 } // namespace xdg
 
 
diff --git a/tests/CMakeLists.txt b/tests/CMakeLists.txt
index 3ed1ecb..8531452 100644
--- a/tests/CMakeLists.txt
+++ b/tests/CMakeLists.txt
@@ -5,6 +5,7 @@ TEST_NAMES
 test_bbox
 test_bvh
 test_closest
+test_occluded
 test_ray_fire
 test_mesh_internal
 test_xdg_interface
diff --git a/tests/test_occluded.cpp b/tests/test_occluded.cpp
new file mode 100644
index 0000000..0ba0014
--- /dev/null
+++ b/tests/test_occluded.cpp
@@ -0,0 +1,34 @@
+
+// for testing
+#include <catch2/catch_test_macros.hpp>
+
+// xdg includes
+#include "xdg/mesh_manager_interface.h"
+#include "xdg/ray_tracing_interface.h"
+
+#include "mesh_mock.h"
+
+using namespace xdg;
+
+TEST_CASE("Test Occluded")
+{
+  std::shared_ptr<MeshManager> mm = std::make_shared<MeshMock>();
+  mm->init(); // this should do nothing, just good practice to call it
+
+  std::shared_ptr<RayTracer> rti = std::make_shared<RayTracer>();
+  rti->register_all_volumes(mm);
+
+  // setup ray to fire that won't hit the mock model
+  Position r {-100.0, 0.0, 0.0};
+  Direction u {1.0, 0.0, 0.0};
+  double dist {0.0};
+
+  MeshID volume = mm->volumes()[0];
+
+  bool result = rti->occluded(volume, r, u, dist);
+  REQUIRE(result == true);
+
+  u = {-1.0, 0.0, 0.0};
+  result = rti->occluded(volume, r, u, dist);
+  REQUIRE(result == false);
+}
\ No newline at end of file