diff --git a/src/RawModel.cpp b/src/RawModel.cpp
index 230b180..1353743 100644
--- a/src/RawModel.cpp
+++ b/src/RawModel.cpp
@@ -269,11 +269,20 @@ void RawModel::Condense()
 
         surfaces.clear();
 
+        std::set<int> survivingSurfaceIds;
         for (auto &triangle : triangles) {
+            int oldSurfaceIndex = triangle.surfaceIndex;
             const RawSurface &surface = oldSurfaces[triangle.surfaceIndex];
             const int surfaceIndex = AddSurface(surface.name.c_str(), surface.id);
             surfaces[surfaceIndex] = surface;
             triangle.surfaceIndex = surfaceIndex;
+            survivingSurfaceIds.emplace(surface.id);
+        }
+        // clear out references to meshes that no longer exist
+        for (auto &node : nodes) {
+            if (node.surfaceId != 0 && survivingSurfaceIds.find(node.surfaceId) == survivingSurfaceIds.end()) {
+                node.surfaceId = 0;
+            }
         }
     }