diff --git a/surface/src/3rdparty/opennurbs/opennurbs_curve.cpp b/surface/src/3rdparty/opennurbs/opennurbs_curve.cpp
index 62516064cfa..1003adbde25 100644
--- a/surface/src/3rdparty/opennurbs/opennurbs_curve.cpp
+++ b/surface/src/3rdparty/opennurbs/opennurbs_curve.cpp
@@ -1182,7 +1182,7 @@ bool ON_Curve::EvaluatePoint( const class ON_ObjRef& objref, ON_3dPoint& P ) con
         ON_3dPoint F1, F2;
         if ( ellipse.GetFoci(F1,F2) )
         {
-          P = ( F1.DistanceTo(Q) <= F1.DistanceTo(Q)) ? F1 : F2;
+          P = ( F1.DistanceTo(Q) <= F2.DistanceTo(Q)) ? F1 : F2;
           rc = true;
         }
       }