diff --git a/Source/Scene/processPbrMaterials.js b/Source/Scene/processPbrMaterials.js
index 8b255bad5cbb..99ec66acf569 100644
--- a/Source/Scene/processPbrMaterials.js
+++ b/Source/Scene/processPbrMaterials.js
@@ -729,7 +729,7 @@ define([
             fragmentShader += '                           gltf_clippingPlanesMatrix[0][1], gltf_clippingPlanesMatrix[1][1], gltf_clippingPlanesMatrix[2][1], \n';
             fragmentShader += '                           gltf_clippingPlanesMatrix[0][2], gltf_clippingPlanesMatrix[1][2], gltf_clippingPlanesMatrix[2][2]); \n';
             fragmentShader += '    const mat3 yUpToZUp = mat3(-1.0, 0.0, 0.0, 0.0, 0.0, -1.0, 0.0, 1.0, 0.0); \n';
-            fragmentShader += '    vec3 cubeDir = yUpToZUp * fixedToENU * n; \n';
+            fragmentShader += '    vec3 cubeDir = normalize(yUpToZUp * fixedToENU * normalize(reflect(-v, n))); \n';
 
             fragmentShader += '#ifdef DIFFUSE_IBL \n';
             fragmentShader += '#ifdef CUSTOM_SPHERICAL_HARMONICS \n';