Volume below a plane

include/ignition/math/Line3.hh

@@ -231,8 +231,9 @@ namespace ignition
 
       /// \brief Calculate shortest distance between line and point
       /// \param[in] _pt Point which we are measuring distance to.
+      /// \param[in] _epsilon Tolerance below which assume this line is a point.
       /// \returns Distance from point to line.
-      public: T Distance(const Vector3<T> &_pt)
+      public: T Distance(const Vector3<T> &_pt, const T _epsilon = 1e-6)
       {
         auto line = this->pts[1] - this->pts[0];
         auto ptTo0 = _pt - this->pts[0];
@@ -251,8 +252,13 @@ namespace ignition
         }
 
         // Distance to point projected onto line
-        auto d = (ptTo0).Cross(line);
-        return d.Length() / (line).Length();
+        auto d = ptTo0.Cross(line);
+
+        // If line has length zero assume its a point.
+        if(line.Length() <= _epsilon)
+          return ptTo0.Length();
+
+        return d.Length() / line.Length();
       }
 
       /// \brief Check if this line intersects the given line segment.