The custom wall "draw" tool is going to be a little bit different from the existing wall tools. Currently I have it so that can select a face (grouped or ungrouped). The face has to be vertical, in more precise terms this means the face normal vector must be perpendicular to the Z axis. Also note that as you hover over the face the nearest vertex is highlighted with the light green circle:
[image: 1782957316187-wall_su1313_800.jpg]
This indicates where the "origin" or start point of the wall will be drawn from. Once you select the face, the tool then goes to phase 2, which allows you to project along the face in one of two directions. This will determine which side is the interior or exterior of the wall:
[image: 1782957320863-wall_su1314_800.jpg]
The thick blue line indicates the ray or vector that is being used to determine which way the wall is facing, also the 3D wireframe indicates the wall's general envelope or geometry.