.. location, doesn't seem too unusual...

You may be right - that it is a more usual combination than I thought. As it will happen with windows too (at least those with an outside wall offset and at an elevation below the top of the lower, sloped wall), it may be something worth reporting. As a bug or feature request.

As for SH3D Source Forge, the most useful models will end up in the contributor library anyway. But it is a good place to exchange/find special models.

..working out the centre of a sloping wall, i'll skip that thx...

Not sure I understand what you mean by working out of the centre... The SH3D split wall command is pretty clever as it will insert correct start and end heights in a sloping walls.

Anyway, glad you found a solution.

ok