Make sure that objects on the desk and floor are not floating.
Ex. model that doesn't snap properly to the desk
If the object pipes down, the bottom line will not be drawn, so you will need to snap it.
Ex. model that does not draw lines by digging
When creating the plan view, make sure that each wall is attached and not floating.
Ex. fallen wall
If there is a gap between the desk and your objects, you can resolve it by selecting the entire object and snapping it to the desk.β’
XYZ axis translation selectable, snapping is automatic