diff --git a/zenovis/src/optx/RenderEngineOptx.cpp b/zenovis/src/optx/RenderEngineOptx.cpp
index 86dfb398e5..3a52826c72 100644
--- a/zenovis/src/optx/RenderEngineOptx.cpp
+++ b/zenovis/src/optx/RenderEngineOptx.cpp
@@ -1372,7 +1372,8 @@ struct RenderEngineOptx : RenderEngine, zeno::disable_copy {
             ensure_shadtmpl(_volume_shader_template);
             ensure_shadtmpl(_light_shader_template);
 
-            if (cachedMeshesMaterials.count("Default")) {
+            //if (cachedMeshesMaterials.count("Default")) 
+            {
                 auto tmp = std::make_shared<ShaderPrepared>();
 
                 tmp->mark = ShaderMark::Mesh;
@@ -1385,7 +1386,8 @@ struct RenderEngineOptx : RenderEngine, zeno::disable_copy {
                 meshMatLUT.insert({"Default", 0});
             }
 
-            if (cachedSphereMaterials.count("Default")) {
+            //if (cachedSphereMaterials.count("Default")) 
+            {
                 auto tmp = std::make_shared<ShaderPrepared>();
 
                 tmp->mark = ShaderMark::Sphere;
diff --git a/zenovis/xinxinoptix/optixPathTracer.cpp b/zenovis/xinxinoptix/optixPathTracer.cpp
index 1122010de4..7e114534fc 100644
--- a/zenovis/xinxinoptix/optixPathTracer.cpp
+++ b/zenovis/xinxinoptix/optixPathTracer.cpp
@@ -744,8 +744,10 @@ static void buildMeshAccel( PathTracerState& state, std::shared_ptr<smallMesh> m
                 ) );
 
     // // Build triangle GAS // // One per SBT record for this build input
+    auto numSbtRecords = g_mtlidlut.empty() ? 1 : g_mtlidlut.size();
+
     std::vector<uint32_t> triangle_input_flags(//MAT_COUNT
-        g_mtlidlut.size(),
+        numSbtRecords,
         OPTIX_GEOMETRY_FLAG_REQUIRE_SINGLE_ANYHIT_CALL);
 
     OptixBuildInput triangle_input                           = {};
@@ -755,7 +757,7 @@ static void buildMeshAccel( PathTracerState& state, std::shared_ptr<smallMesh> m
     triangle_input.triangleArray.numVertices                 = static_cast<uint32_t>( mesh->vertices.size() );
     triangle_input.triangleArray.vertexBuffers               = mesh->vertices.empty() ? nullptr : &dverts;
     triangle_input.triangleArray.flags                       = triangle_input_flags.data();
-    triangle_input.triangleArray.numSbtRecords               = mesh->vertices.empty() ? 1 : g_mtlidlut.size();
+    triangle_input.triangleArray.numSbtRecords               = numSbtRecords;
     triangle_input.triangleArray.sbtIndexOffsetBuffer        = dmats;
     triangle_input.triangleArray.sbtIndexOffsetSizeInBytes   = sizeof( uint32_t );
     triangle_input.triangleArray.sbtIndexOffsetStrideInBytes = sizeof( uint32_t );