Open or Closed Wall
When this function is selected, a wall is added as a closed wall, otherwise the wall is added as an open wall. In an open wall or wall group, the start point can be different than the end point. In a closed wall group the end point is the same as the starting point.
The selection of wall group points is finished with the Confirm function, in which case a wall is drawn and modeled from the last selected wall point to the start point of the wall group.