diff --git a/core/tools.descartes.dql.core.engine/src/tools/descartes/dql/core/engine/util/DoFCrossProductHelper.java b/core/tools.descartes.dql.core.engine/src/tools/descartes/dql/core/engine/util/DoFCrossProductHelper.java
index 2def448d778429e9a0dee6fb353ccd836f9609a3..82cda6539c8de7c741eb09b500ede9f5ef5a0f91 100644
--- a/core/tools.descartes.dql.core.engine/src/tools/descartes/dql/core/engine/util/DoFCrossProductHelper.java
+++ b/core/tools.descartes.dql.core.engine/src/tools/descartes/dql/core/engine/util/DoFCrossProductHelper.java
@@ -50,10 +50,10 @@ public class DoFCrossProductHelper {
 	 * @return List of DoF-combination. Each list element contains one possible
 	 *         combination
 	 */
-	public List<HashMap<DoF, String>> calculateCrossProduct(EntityMapping input) {
-		this.possibleDofValues = getPossibleDofValues(input);
-		List<HashMap<DoF, String>> result = recursiveCrossProduct();
-
+	public static List<HashMap<DoF, String>> calculateCrossProduct(EntityMapping input) {
+		DoFCrossProductHelper helper = new DoFCrossProductHelper();
+		helper.possibleDofValues = helper.getPossibleDofValues(input);
+		List<HashMap<DoF, String>> result = helper.recursiveCrossProduct();
 		return result;
 	}