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side walls in dormers?


hey everyone,

i can't figure out how to trim, or create side walls for a roof dormer that are trimmed to the main roof slope, so that the walls don't extend down to the floor. see the pic attached. i i have tried trim to roof or shell, but the whole wall disappears. 

Screen Shot 2022-11-17 at 15.12.57.png
MAC Studio 2022 M1 Max, 32 GB RAM, 10 cores, AC26 5003 Apple Silicon USA
Barry Kelly

Have tried a Solid Element Operation?

The main roof is the operator.

The side walls are the targets.

Subtract with downward extrusion.

That should do it.




One of the forum moderators.
Versions 6.5 to 27
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Lenovo Thinkpad - i7-1270P 2.20 GHz, 32GB RAM, Nvidia T550, Windows 11

well is sort of works, but i would need to line up the drywall skin with the roof opening and although the wall is cut, what i see is a section through the roof with all the skins. idealy i need the inside skins,(drywall) to intersect.

MAC Studio 2022 M1 Max, 32 GB RAM, 10 cores, AC26 5003 Apple Silicon USA

Some kind of better workflow using shells, because shells can do seide-walls better: (german - just turn the sound down..)


AC5.5-AC27EduAut, PC-Win10, MacbookAirM1, MacbookM1Max, Win-I7+Nvidia

This is yet another situation which highlights the need for a new more general approach to modelling in AC. Similar to beams there is functionality tied to shells that would be very useful when modelling walls, slabs and roofs. The start/end angle is very useful when modelling walls with angled sides such as for dormers or gables since it gets correctly displayed in plan. But as always the usefulness is compromised by imposed presuppositions of which building part the created geometry should represent - in this case one where there isn't doors, nor windows - only skylights...