diff --git a/src/extras/BuildingShapeUtils.js b/src/extras/BuildingShapeUtils.js
index 6c5ae8d..2c4ab81 100644
--- a/src/extras/BuildingShapeUtils.js
+++ b/src/extras/BuildingShapeUtils.js
@@ -81,11 +81,24 @@ class BuildingShapeUtils extends ShapeUtils {
    * @return {[DOM.Element]} array of closed ways.
    */
   static combineWays(ways) {
+    const validWays = [];
+
+    for (const way of ways) {
+      if (BuildingShapeUtils.isSelfIntersecting(way)) {
+        const id = way.getAttribute('id');
+        const msg = 'Way ' + id + ' is self-intersecting';
+        window.printError(msg);
+      } else {
+        const i = 3 + 'q';
+        validWays.push(way);
+      }
+    }
+
     const closedWays = [];
     const wayBegins = {};
     const wayEnds = {};
 
-    ways.forEach(w => {
+    validWays.forEach(w => {
       const firstNodeID = w.querySelector('nd').getAttribute('ref');
       if (wayBegins[firstNodeID]) {
         wayBegins[firstNodeID].push(w);
@@ -142,7 +155,7 @@ class BuildingShapeUtils extends ShapeUtils {
       return [];
     }
 
-    ways.forEach(w => {
+    validWays.forEach(w => {
       const wayID = w.getAttribute('id');
       if (usedWays.has(wayID)){
         return;
diff --git a/test/combine_ways.test.js b/test/combine_ways.test.js
index eeabde7..e0cf1c1 100644
--- a/test/combine_ways.test.js
+++ b/test/combine_ways.test.js
@@ -13,38 +13,42 @@ import { Shape } from 'three';
 import { BuildingShapeUtils } from '../src/extras/BuildingShapeUtils.js';
 // import { JSDOM } from 'jsdom';
 
+beforeEach(() => {
+  errorMsgs = [];
+});
+
 describe.each([
   [
     ['<way id="1"><nd ref="1"/><nd ref="2"/><nd ref="3"/><nd ref="4"/></way>',
-    ], 0, 0, 'Single Open Way',
+    ], 0, 0, [], 'Single Open Way',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="2"/><nd ref="3"/></way>',
       '<way id="3"><nd ref="3"/><nd ref="1"/></way>',
-    ], 1, 4, 'Test combining 3 ways 1->2->3',
+    ], 1, 4, [], 'Test combining 3 ways 1->2->3',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="3"/><nd ref="1"/></way>',
       '<way id="3"><nd ref="2"/><nd ref="3"/></way>',
-    ], 1, 4, 'Test combining 3 ways 2->1->3',
+    ], 1, 4, [], 'Test combining 3 ways 2->1->3',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="3"/><nd ref="2"/></way>',
       '<way id="3"><nd ref="3"/><nd ref="1"/></way>',
-    ], 1, 4, 'Test combining tip to tip',
+    ], 1, 4, [], 'Test combining tip to tip',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="1"/><nd ref="3"/></way>',
       '<way id="3"><nd ref="2"/><nd ref="3"/></way>',
-    ], 1, 4, 'Test combining tail to tail',
+    ], 1, 4, [], 'Test combining tail to tail',
   ],
   [
     [
@@ -52,20 +56,20 @@ describe.each([
       '<way id="2"><nd ref="3"/><nd ref="4"/></way>',
       '<way id="3"><nd ref="4"/><nd ref="1"/></way>',
       '<way id="4"><nd ref="2"/><nd ref="3"/></way>',
-    ], 1, 5, 'Test combining 4 ways',
+    ], 1, 5, [], 'Test combining 4 ways',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="3"/><nd ref="2"/></way>',
-    ], 0, 0, 'Test combining 2 open ways into one open way',
+    ], 0, 0, [], 'Test combining 2 open ways into one open way',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="3"/><nd ref="2"/></way>',
       '<way id="3"><nd ref="4"/><nd ref="5"/></way>',
-    ], 0, 0, 'Test combining 3 open ways into 2 open ways',
+    ], 0, 0, [], 'Test combining 3 open ways into 2 open ways',
   ],
   [
     [
@@ -73,28 +77,35 @@ describe.each([
       '<way id="2"><nd ref="2"/><nd ref="4"/></way>',
       '<way id="3"><nd ref="2"/><nd ref="3"/></way>',
       '<way id="4"><nd ref="1"/><nd ref="3"/></way>',
-    ], 1, 4, 'Combining 4 open ways into 1 closed & 1 remaining open way',
+    ], 1, 4, [], 'Combining 4 open ways into 1 closed & 1 remaining open way',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/><nd ref="3"/></way>',
       '<way id="2"><nd ref="3"/><nd ref="5"/><nd ref="1"/></way>',
       '<way id="3"><nd ref="3"/><nd ref="4"/><nd ref="1"/></way>',
-    ], 1, 5, 'Dealing with amiguity. Only make one closed way',
+    ], 1, 5, [], 'Dealing with amiguity. Only make one closed way',
   ],
+  //[
+  //  [
+  //    '<way id="1"><nd ref="1"/><nd ref="2"/><nd ref="3"/></way>',
+  //    '<way id="2"><nd ref="3"/><nd ref="4"/><nd ref="2"/><nd ref="5"/><nd ref="1"/></way>',
+  //  ], 0, 0, [], 'Closed way is self intersecting',
+  //],
   [
     [
-      '<way id="1"><nd ref="1"/><nd ref="2"/><nd ref="3"/></way>',
-      '<way id="2"><nd ref="3"/><nd ref="4"/><nd ref="2"/><nd ref="5"/><nd ref="1"/></way>',
-    ], 0, 0, 'Closed way is self intersecting',
+      '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
+      '<way id="2"><nd ref="2"/><nd ref="3"/><nd ref="4"/><nd ref="5"/><nd ref="3"/><nd ref="1"/></way>',
+    ], 0, 0, ['Way 2 is self-intersecting'], 'Open way is self intersecting',
   ],
   [
     [
       '<way id="1"><nd ref="1"/><nd ref="2"/></way>',
       '<way id="2"><nd ref="2"/><nd ref="3"/><nd ref="4"/><nd ref="5"/><nd ref="3"/><nd ref="1"/></way>',
-    ], 0, 0, 'Open way is self intersecting',
+      '<way id="3"><nd ref="2"/><nd ref="3"/><nd ref="1"/></way>',
+    ], 1, 4, ['Way 2 is self-intersecting'], 'Open way is self intersecting, but ring formed',
   ],
-])('Combine Ways', (ways, length, nodes, description) => {
+])('Combine Ways', (ways, length, nodes, errors, description) => {
   test(`${description}`, () => {
     let parser = new window.DOMParser();
     const xml = [];
@@ -103,6 +114,12 @@ describe.each([
     }
     let result = BuildingShapeUtils.combineWays(xml);
     expect(result.length).toBe(length);
+    expect(errorMsgs.length).toBe(errors.length);
+    if (errors.length) {
+      for (const error of errors) {
+        expect(errorMsgs.shift()).toBe(error);
+      }
+    }
     if (length) {
       expect(BuildingShapeUtils.isClosed(result[0]));
       expect(BuildingShapeUtils.isSelfIntersecting(result[0])).toBe(false);
@@ -110,3 +127,11 @@ describe.each([
     }
   });
 });
+
+window.printError = printError;
+
+var errorMsgs = [];
+
+function printError(txt) {
+  errorMsgs.push(txt);
+}