diff --git a/source/MaterialXGenGlsl/Nodes/ViewDirectionNodeGlsl.cpp b/source/MaterialXGenGlsl/Nodes/ViewDirectionNodeGlsl.cpp
index 198465c9af..f9714b5d33 100644
--- a/source/MaterialXGenGlsl/Nodes/ViewDirectionNodeGlsl.cpp
+++ b/source/MaterialXGenGlsl/Nodes/ViewDirectionNodeGlsl.cpp
@@ -26,12 +26,12 @@ void ViewDirectionNodeGlsl::createVariables(const ShaderNode&, GenContext&, Shad
 
 void ViewDirectionNodeGlsl::emitFunctionCall(const ShaderNode& node, GenContext& context, ShaderStage& stage) const
 {
-    const ShaderGenerator& shadergen = context.getShaderGenerator();
+    const GlslShaderGenerator& shadergen = static_cast<const GlslShaderGenerator&>(context.getShaderGenerator());
 
     DEFINE_SHADER_STAGE(stage, Stage::VERTEX)
     {
         VariableBlock& vertexData = stage.getOutputBlock(HW::VERTEX_DATA);
-        const string prefix = vertexData.getInstance() + ".";
+        const string prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort* position = vertexData[HW::T_POSITION_WORLD];
         if (!position->isEmitted())
         {
@@ -43,7 +43,7 @@ void ViewDirectionNodeGlsl::emitFunctionCall(const ShaderNode& node, GenContext&
     DEFINE_SHADER_STAGE(stage, Stage::PIXEL)
     {
         VariableBlock& vertexData = stage.getInputBlock(HW::VERTEX_DATA);
-        const string prefix = vertexData.getInstance() + ".";
+        const string prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort* position = vertexData[HW::T_POSITION_WORLD];
         shadergen.emitLineBegin(stage);
         shadergen.emitOutput(node.getOutput(), true, false, context, stage);
diff --git a/source/MaterialXGenMsl/Nodes/ViewDirectionNodeMsl.cpp b/source/MaterialXGenMsl/Nodes/ViewDirectionNodeMsl.cpp
index 84a6b02b4f..1443b5c320 100644
--- a/source/MaterialXGenMsl/Nodes/ViewDirectionNodeMsl.cpp
+++ b/source/MaterialXGenMsl/Nodes/ViewDirectionNodeMsl.cpp
@@ -26,12 +26,12 @@ void ViewDirectionNodeMsl::createVariables(const ShaderNode&, GenContext&, Shade
 
 void ViewDirectionNodeMsl::emitFunctionCall(const ShaderNode& node, GenContext& context, ShaderStage& stage) const
 {
-    const ShaderGenerator& shadergen = context.getShaderGenerator();
+    const MslShaderGenerator& shadergen = static_cast<const MslShaderGenerator&>(context.getShaderGenerator());
 
     DEFINE_SHADER_STAGE(stage, Stage::VERTEX)
     {
         VariableBlock& vertexData = stage.getOutputBlock(HW::VERTEX_DATA);
-        const string prefix = vertexData.getInstance() + ".";
+        const string prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort* position = vertexData[HW::T_POSITION_WORLD];
         if (!position->isEmitted())
         {
@@ -43,7 +43,7 @@ void ViewDirectionNodeMsl::emitFunctionCall(const ShaderNode& node, GenContext&
     DEFINE_SHADER_STAGE(stage, Stage::PIXEL)
     {
         VariableBlock& vertexData = stage.getInputBlock(HW::VERTEX_DATA);
-        const string prefix = vertexData.getInstance() + ".";
+        const string prefix = shadergen.getVertexDataPrefix(vertexData);
         ShaderPort* position = vertexData[HW::T_POSITION_WORLD];
         shadergen.emitLineBegin(stage);
         shadergen.emitOutput(node.getOutput(), true, false, context, stage);