Make access to properties protected (accessible to children).

+mgen/MgGeoLine3Point.m

 classdef MgGeoLine3Point < mgen.MgGeoLine2Point
     % A 3-point line of the geometry
 
-    properties (Access = private)
-        geoPoints = mgen.MgGeoPoint.empty(0,3);
-        gridNodes = mgen.MgGridNode.empty(0,0);
+    properties (Access = protected)
 
-        numTargetGridNodes  = 0;
-
-        switchGridNode = false;
-        switchGeoPoint = false;
-
-        normFunction = mgen.MgNormFunction();
     end
 
     methods
@@ -52,6 +44,10 @@ classdef MgGeoLine3Point < mgen.MgGeoLine2Point
         end
 
         function setNumTargetGridNodes(self, num)
+            % if num <= 3
+            %   num = 3;
+            % end
+            %
             self.numTargetGridNodes = num;
         end