diff --git a/WFObj.cc b/WFObj.cc
index 0dfe42b..184fcdd 100644
--- a/WFObj.cc
+++ b/WFObj.cc
@@ -265,9 +265,25 @@ vector<WFObj::Face> WFObj::readFaces(const std::vector<std::string> & parts)
 {
     vector<Face> faces;
     VertexRef refs[4];
-    for (int i = 1, len = parts.size(); i < len && i <= 4; i++)
+    int parts_len = parts.size();
+    if (parts_len < 3 || parts_len > 4)
     {
+        cerr << "WFObj: error: faces can only have 3 or 4 vertices!" << endl;
+        return faces;
+    }
+    for (int i = 1; i <= parts_len; i++)
         refs[i - 1] = readVertexRef(parts[i]);
+    Face f;
+    f.vertices[0] = refs[0];
+    f.vertices[1] = refs[1];
+    f.vertices[2] = refs[2];
+    faces.push_back(f);
+    if (parts_len == 4)
+    {
+        f.vertices[0] = refs[2];
+        f.vertices[1] = refs[3];
+        f.vertices[2] = refs[0];
+        faces.push_back(f);
     }
     return faces;
 }