If it is necessary to add new vertices to the Opening Section boundary, this can be done with the Add Vertices option. To add vertices:
First make sure the Opening Section View is selected.
Select Add Vertices from the Sidebar, the Opening menu or the right-click menu.
You may enter the coordinates of a new vertex graphically with the mouse, or by keyboard entry in the prompt line:
As you move the mouse, you will see a small red cross which snaps to the nearest point on the Opening Section boundary, following the cursor movement. You can use this as a guide to graphically add a new vertex, by clicking the left mouse button when the red cross is at the desired location. Note that the coordinates displayed in the Status Bar at the lower right of the screen, are the coordinates of the red cross on the boundary, and NOT the cursor coordinates.
You can enter the coordinates of a new vertex in the prompt line, however, the coordinates must be either exactly ON the Opening Section boundary, or very close to the boundary, in order for a vertex to be added. If the point entered is too far from the boundary, you will see a warning dialog, and be prompted to enter new coordinates. If the point is only slightly off, a vertex will be added at the nearest point on the boundary.
Repeat step 3 for each new vertex that you wish to add. You can add any number of new vertices without exiting the Add Vertices option. When you are finished, press Enter or right-click and select Done.
Note: if you enter an incorrect vertex while using Add Vertices, you cannot Cancel or undo while you are in Add Vertices mode. If this occurs, exit the Add Vertices option and select the Undo option. This will remove all of the vertices which you have just added. Or you can use the Delete Vertices option to remove incorrect vertices.