Hi Mike.

It is necessary to lower the roof or rather the level in which it is defined because....

3
2
1
0

Means I can see level 0 'through the floor' when working on level 1 but if I move up to level 2 to make a change I cannot see level 0 so there I am blind.

So I need to change the relative heights

3
1
2
0

Now I can see level 0 'through the floor' whilst working on level 2 - I can edit the roof and check it fits relative to whats going on on the ground floor.

It's not a "do once" thing for me - constantly tweaking things and ripple adjustments move out through the building.

The behaviour is documented in the tips section

"How To Design A Split Level House"

Quote: "Unfortunately, Sweet Home 3D draws only walls of the previous level in light grey. Therefore, the shop walls drawn at Level 0 won't appear at Level 2, because its previous level is Level 1 and not Level 0"

The suggested workaround there is to copy 3d objects as markers between floors but I just move my levels up and down - my levels are actually
named according to their elevation so I do not forget and tap in the wrong number when I restore the level to its normal height after the edit.

Its not a hassle for me - just tap in a number before the edit and restore it after.

Its all really just about being able to see the ground floor items when editing the profile of the roof, editing a skylight or similar.

What I am really pleased about is that now I am working this way using dummy floors as ceilings then a tweak only involves an edit to a boundary
whereas before it meant messing around with creating OBJ files and exporting them, repositioning them and so on.