diff --git a/Source/ThirdParty/GltfPipeline/addPipelineExtras.js b/Source/ThirdParty/GltfPipeline/addPipelineExtras.js
index 26770de6b816..5f5dc2b54656 100644
--- a/Source/ThirdParty/GltfPipeline/addPipelineExtras.js
+++ b/Source/ThirdParty/GltfPipeline/addPipelineExtras.js
@@ -56,6 +56,11 @@ define([
         gltf.extras._pipeline = defaultValue(gltf.extras._pipeline, {});
         gltf.asset = defaultValue(gltf.asset, {});
         gltf.asset.extras = defaultValue(gltf.asset.extras, {});
+        if (defined(gltf.asset.extras) && typeof(gltf.asset.extras) !== 'object') {
+            gltf.asset.extras = {
+                extras : gltf.asset.extras
+            };
+        }
         gltf.asset.extras._pipeline = defaultValue(gltf.asset.extras._pipeline, {});
         return gltf;
     }
diff --git a/Source/ThirdParty/GltfPipeline/processModelMaterialsCommon.js b/Source/ThirdParty/GltfPipeline/processModelMaterialsCommon.js
index 3fe20099f819..9608b4de179d 100644
--- a/Source/ThirdParty/GltfPipeline/processModelMaterialsCommon.js
+++ b/Source/ThirdParty/GltfPipeline/processModelMaterialsCommon.js
@@ -541,7 +541,8 @@ define([
             } else {
                 fragmentLightingBlock += '  vec3 l = vec3(0.0, 0.0, 1.0);\n';
             }
-            fragmentLightingBlock += '  diffuseLight += vec3(1.0, 1.0, 1.0) * max(dot(normal,l), 0.);\n';
+            var minimumLighting = optimizeForCesium ? 0.2 : 0.0;
+            fragmentLightingBlock += '  diffuseLight += vec3(1.0, 1.0, 1.0) * max(dot(normal,l), ' + minimumLighting + ');\n';
 
             if (hasSpecular) {
                 if (lightingModel === 'BLINN') {
diff --git a/Source/ThirdParty/GltfPipeline/updateVersion.js b/Source/ThirdParty/GltfPipeline/updateVersion.js
index d6d42ea1535b..e357b0e8cf37 100644
--- a/Source/ThirdParty/GltfPipeline/updateVersion.js
+++ b/Source/ThirdParty/GltfPipeline/updateVersion.js
@@ -225,7 +225,7 @@ define([
                 var value = object[id];
                 mapping[id] = array.length;
                 array.push(value);
-                if (!defined(value.name)) {
+                if (!defined(value.name) && typeof(value) === 'object') {
                     value.name = id;
                 }
             }
@@ -449,6 +449,7 @@ define([
                     var target = channel.target;
                     if (defined(target)) {
                         target.node = globalMapping.nodes[target.id];
+                        delete target.id;
                     }
                 }
             }
@@ -737,7 +738,7 @@ define([
                     bufferViewsToDelete[oldBufferViewId] = true;
                 }
                 var bufferView = clone(bufferViews[oldBufferViewId]);
-                var accessorByteStride = getAccessorByteStride(gltf, accessor);
+                var accessorByteStride = (defined(accessor.byteStride) && accessor.byteStride !== 0) ? accessor.byteStride : getAccessorByteStride(gltf, accessor);
                 if (defined(accessorByteStride)) {
                     bufferView.byteStride = accessorByteStride;
                     if (bufferView.byteStride !== 0) {