topic Re: Can't create an arch in Modeling

Can't create an arch

Anonymous — Tue, 23 May 2023 13:02:28 GMT

Hi, I've been trying to create an arch starting from a section line I created and using the curved roof slab tool. However, when I do in in 2D, for some reason ArchiCAD switches it to the normal roof slab and creates a normal straight slab. Any suggestions? What am I doing wrong?

Thanks a lot!

Re: Can't create an arch

Erika Epstein — Tue, 16 Jun 2009 19:13:13 GMT

You need to magic-wand the roof onto the arch.

Activate the roof tool.
Set the geometry method to the curved roof.
Magic want the roof onto the curve. You will get many small straight segments of roof simulating the curve. If you want a true arch semicircle, create a custom one using the Profile manager.

Are you trying to create a freestanding arch?

Re: Can't create an arch

Anonymous — Thu, 18 Jun 2009 11:32:25 GMT

Actually it's about a renovation project of an historic building. The structure of each stair fly is an arch, which makes it quite tricky to draw...

I've created the actual steps with the stair tool. I've then added each arch part with a custom-shaped GDL object (old building in new BIM software = a lot of patience required). This works well in building sections, but I can't get the plan view to cut the GDL objects, so the plan I get is not correct.

I'm now trying to replace these GDL objects with one wall each, as wide as the relative stair fly. I can shape the top part of these walls to fit the stair fly using the Solid Operation tool (subtract with above extrusion), and I need to create an arch-shaped roof slab to do the same for the bottom part.

I'll try to follow your tip, thanks!

Enrico

Re: Can't create an arch

Erika Epstein — Thu, 18 Jun 2009 13:49:46 GMT

Would it be easier to place a wall under the stair the depth of the stair. In the place arched openings to size. Then the only trimming needed would be the wall by the stair?

Re: Can't create an arch

rocorona — Thu, 18 Jun 2009 20:03:36 GMT

Enrico wrote:
However, when I do in in 2D, for some reason ArchiCAD switches it to the normal roof slab and creates a normal straight slab.

The fault, creating a vault roof, can be the size of it (=stair width). Maybe you need to adjust the Magic Wand Settings before.

Enrico wrote:
I'm now trying to replace these GDL objects with one wall each, as wide as the relative stair fly. I can shape the top part of these walls to fit the stair fly using the Solid Operation tool (subtract with above extrusion), and I need to create an arch-shaped roof slab to do the same for the bottom part.

You can use a beam with custom profile, or a Library object (Cylinder, Vault) instead of the arch-roof. This can be easier and not so oddly segmented.

Enrico wrote:
This works well in building sections, but I can't get the plan view to cut the GDL objects, so the plan I get is not correct.

If you are satisfied with the 3D of your object you are 99% done... You can simply draw the desired plan symbol in the object 2D drawing window (and delete all from the 2D script).
I think you can also add some instruction to the 3D script, to place a cutting plane if the "context" is the storey plan window, and use PROJECT2 to get that view in 2D... (not tested).

Re: Can't create an arch

Anonymous — Mon, 22 Jun 2009 16:24:01 GMT

I followed your tip and used a wall with custom profile, this solved my problem.

Thanks!