In Revit when dimensioning it can be easy to select a common line inside a wall like the plasterboard and not the inside face, especially if you have scale that makes distinguishing between the lines difficult.
The below two images are of the same wall, by changing the scale the plaster layer is now hidden in the lines but the two lines still exist making it indistinguishable to which one you could be selecting.
By default Common Edges is on, this makes the layers inside the walls selectable.
To turn this feature off and make only the outside faces of the wall selectable we need to turn off Common Edges in Visibility Graphics. Here is what to do:
1. Go into Visibility Graphics, the keyboard shortcut is “VG”.
2. On the tab “Model Categories” scroll down to walls and Expand.
3. Under “Walls” you will see “Common Edges”, untick this.
4. Click OK.
This has now turned off the Common Edges in walls.
As you can see there is no longer a line between the different layers of the wall.