one part of the wall vanishes. why?

[Anonymous]

Hello.
I do not know what happens to this wall, but its part under the roof vanishes, both in 3D (as in the attached picture) and in section.
I should add the wall is clear of any intersections.
Is it a problem of priority?
Thank you.

[Laszlo Nagy]

It looks like the Wall has been cropped by the Roof or trimmed by the Roof's Trimming Body.

Did you use the Crop to Single-Plan Roof command on the Wall?

Or did you use the Trim Elements to Roof/Shell command on the Wall?

[Anonymous]

Hello and thank you for your reply.
No, I don't think I did. I almost never do. What I usually use is Connect > Subtract. But, even if I had used these commands, shouldn't they have been cancelled by the Cancel all connections command, which I am sure I used for the wall in the very end?
Thank you.

[DGSketcher]

I have had walls in projects moved from earlier versions which seem to randomly inherit cropping. If you have cleared all connections and you are sure there are no priority issues then it may be cropping as Lazlo suggests. Cropping seems to be unfavourably buried in the menus especially removing cropping. Perhaps its days are numbered, but this may help...

https://helpcenter.graphisoft.com/guides/archicad-21/archicad-21-reference-guide/elements-of-the-vir...