//------------------------------------------------------------------------------
        private void buildDisplayLists_LN()
        {
            // find all the point in the bbbox
            if (NumPts > 0)
            {
                _DisplayListLN = Gl.glGenLists(1);
                Gl.glNewList(_DisplayListLN, Gl.GL_COMPILE);

                // draw the box
                Gl.glDisable(Gl.GL_LIGHTING);
                Gl.glEnable(Gl.GL_LINE_SMOOTH_HINT);
                GL_Draw.GLBBCube(_bbMin, _bbMax, Colour.Lemon_Chiffon());
                Gl.glDisable(Gl.GL_LINE_SMOOTH_HINT);
                Gl.glEnable(Gl.GL_LIGHTING);
                Gl.glEndList();
            }
        }
 //------------------------------------------------------------------------------
 private void buildDisplayLists_CentreNorm(bool centroid)
 {
     _DispLstCentreNorm = Gl.glGenLists(1);
     Gl.glNewList(_DispLstCentreNorm, Gl.GL_COMPILE);
     Gl.glDisable(Gl.GL_LIGHTING);
     GL_Draw.GLBBCube(_bbMin, _bbMax, Colour.Dark_Orchid());
     displayEigen();
     displayAdjacent(centroid);
     Gl.glPointSize(5.0f);
     Gl.glEnable(Gl.GL_POINT_SMOOTH);
     Gl.glBegin(Gl.GL_POINTS);
     Gl.glColor3d(1.0d, 0.0d, 0.0d);
     Gl.glVertex3d(Centre._X, Centre._Y, Centre._Z);
     Gl.glEnd();
     Gl.glDisable(Gl.GL_POINT_SMOOTH);
     Gl.glEnable(Gl.GL_LIGHTING);
     Gl.glEndList();
 }