Getting composite walls to clean up with composite roofs

[Paul King]

Has anyone come up with a way to get composite walls to clean up with composite roofs in section?

I have a composite roof used as a suspended ceiling, with a skin used to represent ceiling battens and a skin for plasterboard.

I have a composite wall used as the vertical face of a ceiling bulkhead, with a skin for plasterboard, and a skin for timber framing

The plasterboard material is the same for both composite elements, and the ceiling battens material priority is the same as the wall framing material priority.  Intersection priority for layers containing wall and ceiling elements are the same. 

Both elements are new, and their edges are perfectly aligned to meet at a corner in section

I have tried merging the two elements.

However nothing seems to result in a clean intersection, where the cut view shows plasterboard wrapping down the bulkhead wall and across the ceiling below.   

What am I likely doing wrong?

[Erwin Edel]

The trick lies with the battens and timber framing building materials. They need to be lower than that of the plasterboard.

[Paul King]

I tried swapping them, but no change for me.

Philosophically, I am not clear why swapping would make a difference, at least in this simple situation;  whether the higher priority material is on the insides or outsides of the two composite elements that meet in an 'L' shape, surely like priority should still clean up with like priority, and because each element only has two skins and the same very simple topology (plasterboard outside, framing/battens inside), there is no reason for the outer plasterboard skin of one element to need penetrate the battens / framing skin of the opposing element in order to reach the plasterboard skin of the other element.

I hope that makes sense?

[Erwin Edel]

I'm not going to argue against logic, but I'm afraid this is how ArchiCAD behaves 🙂

That said, I think this is the connection you are trying to make?

The white panel (gypsum) has prio 310, the air layer (batten) has prio 265 and the brown wood panel has prio 285.

Vertical element is a wall, horizontal element is a roof. Connection made by using merge. Both elements are 'clashing' without the merge, so drawn through eachother without merge:

If this isn't what you are trying to solve, then I misunderstood.

[Paul King]

Hi Erwin.  You have the right idea.  and that is pretty much what I am doing (or attempting) - including having same highest priority for plasterboard - but merge just makes things worse rather than better - at least within the building.

Just tried the same exercise off to one side of the building with a copy of same elements, and it cleans up normally.

Suggests to me there is probably a hidden element interacting somehow to prevent clean up - so guess I just have to work though layer combinations in all saved views.

However not all is solved - when I add another higher ceiling, this one still won't clean up - paossibly because corner geometry is reversed

[Erwin Edel]

As a workaround you can give roof edges a 45° or 135° angle, which ussually helps with the connection.

[Paul King]

I found this worked for me in 3D when creating some skylight reveals recently, though in my testing, this any edge angle that is not vertical then messes up the reflected ceiling plan with extra lines, or incorrect edge line location in plan (depending on whether you use legacy mode for roof display) - either way forcing manual 2D fills and linework to be overlaid to compensate.

Hard to escape the feeling that ArchiCAD is still only around 15% complete in its ability to manipulate elements and represent what is required in all views in a swift, intuitive and integrated way.

[Erwin Edel]

I've had some good results with complex profile beams as ceilings, which you can show as simple outline (overhead), but it won't work in every scenario.

[Paul King]

That is a good idea.  Sadly mine is one of those scenarios where it probably would not help (at least not easily); a series of holes in the ceiling cut for asymmetric plasterboard skylight reveals...

[Erwin Edel]

The opening tool might work for that, it should project correctly too.