diff --git a/Source/DataSources/PlaneGeometryUpdater.js b/Source/DataSources/PlaneGeometryUpdater.js
index 47836752e4d2..811d23952ac6 100644
--- a/Source/DataSources/PlaneGeometryUpdater.js
+++ b/Source/DataSources/PlaneGeometryUpdater.js
@@ -264,7 +264,7 @@ define([
         Cartesian3.normalize(transformedNormal, transformedNormal);
 
         var up = ellipsoid.geodeticSurfaceNormal(translation, scratchAxis2);
-        if (Cartesian3.equalsEpsilon(up, transformedNormal, CesiumMath.EPSILON8)) {
+        if (CesiumMath.equalsEpsilon(Math.abs(Cartesian3.dot(up, transformedNormal)), 1.0, CesiumMath.EPSILON8)) {
             up = Cartesian3.clone(Cartesian3.UNIT_Z, up);
         }
 
@@ -285,5 +285,10 @@ define([
         return Matrix4.fromTranslationQuaternionRotationScale(translation, rotation, scale, result);
     }
 
+    /**
+     * @private
+     */
+    PlaneGeometryUpdater.createPrimitiveMatrix = createPrimitiveMatrix;
+
     return PlaneGeometryUpdater;
 });