Index: /applications/editors/josm/plugins/buildings_tools/src/buildings_tools/Building.java
===================================================================
--- /applications/editors/josm/plugins/buildings_tools/src/buildings_tools/Building.java	(revision 21875)
+++ /applications/editors/josm/plugins/buildings_tools/src/buildings_tools/Building.java	(revision 21876)
@@ -238,5 +238,5 @@
 		Way w = new Way();
 		w.addNode(nodes[0]);
-		if (projection2(en[2]) > 0) {
+		if (projection2(en[2]) > 0 ^ len < 0) {
 			w.addNode(nodes[1]);
 			w.addNode(nodes[2]);