topic Re: Wall and slab accessories automatic cut in GDL

Wall and slab accessories automatic cut

B_Migito — Mon, 19 May 2025 19:03:36 GMT

Hi all,

I've created a wall accessory and a sloped slab accessory but there is a problem with how they interact with the rest of the model

For the wall accessory, I've used the uwbp and uwtp trick to make them react to slabs and other elements connected to the top and bottom of the wall : elements like slab (with the slab tool)

My question is (if possible) : How do I make them react to other elements like other slab accessories ?

Below is a screenshot of a native concrete wall with my wall accessory, native concrete slab with my sloped slab accessory.

The connection between the wall accessory and the slab accessory is what I'm trying to fix.

And in 2d - section

The problem is the same with ArchiCAD native wall and slab accessories (see below)

For top connected element, like the slab of the next story above, I don't have that problem.

But for any other elements (like ceiling), I had to use SEO if I want to achieve a similar result so I added a control hotspot to change the height of the wall accessory

All of this was created using ArchiCAD 28.1.1 on MacOS Sequoia 15.3.2

Re: Wall and slab accessories automatic cut

Barry Kelly — Tue, 20 May 2025 00:49:23 GMT

Accessories are object that read the geometry information from the element they are associated to.

So a wall accessory will read the shape of the wall and any door/window openings (not opening tool openings).

The objects will not react to any other objects or elements, so you will have to use SEO to trim them or as you mentioned a hotspot that can override the shape of the accessory.

I am not sure what you mean by the "uwbp and uwtp trick".

Could you explain more what that is please?

Barry.

Re: Wall and slab accessories automatic cut

Pertti Paasky — Tue, 20 May 2025 07:02:27 GMT

There is a limitation with the SEO tool and accessory objects. Every time you update the accessory object you have to do the SEO operation again.

Re: Wall and slab accessories automatic cut

Barry Kelly — Tue, 20 May 2025 07:53:59 GMT

@Pertti Paasky wrote:

There is a limitation with the SEO tool and accessory objects. Every time you update the accessory object you have to do the SEO operation again.

Correct.

I always forget that.

Barry.

Re: Wall and slab accessories automatic cut

B_Migito — Tue, 20 May 2025 12:01:58 GMT

Yes, and it's quite annoying to have to redo it every time 😔

Re: Wall and slab accessories automatic cut

B_Migito — Tue, 20 May 2025 12:37:20 GMT

In the ArchiCAD wall accessory, there are parameters to control the top and bottom cuts of the shape

Here was my thoughts process.

Since there are ways to cut the wall accessory based on interacting elements (ie slab in contact of the wall, other connecting walls, etc.), I was looking for :

A better understanding of how that function works
How could I use that to my advantage with other non specific objects

I started with testing every native ArchiCAD tools and objects that would interact with my accessories

Then, based on my finding, tried to add to that list new cut_set variables.

I should specify that I still don't understand the exactly how this works but since it's a fixed array, I could add more to dim cut_set[i] but there are two issues :

How would ArchiCAD knows that cut_set[7] is for my ceiling slab and cut_set[9] is for skirting boards (plinths)
How could I specify the cut I want from that. In the base object, that cut is a basic SEO (substraction) but I want, for the ceiling as an example, a substraction with upwards extrusion

In the last image (with Next story up), the ceiling is a basic slab but the wall accessory doesn't react to it like it does to the slab above so it's not exactly the type of elements that determines the cut.

And if it's not the type of element, it might be the position of the element.

So I started moving slabs left and right, up and down, only to realize that the building material of the element was also a criteria for the cuts...

Re: Wall and slab accessories automatic cut

Toper Barrientos — Wed, 21 May 2025 01:59:43 GMT

hi Team.

I dabbled with such case as well & it be solved by pure GDL alone...sadly.

My work around is to employ an adjustable CUTplane command at top & bottom of the "wall accessory". I also provided a 3d graphical hotspot , which i can adjust in section or 3d view. I manage the typologies of these wall objects with respect to room application (toilet vs. office vs. units w/o ceiling or flr finishes) using favorites.

Re: Wall and slab accessories automatic cut

B_Migito — Wed, 21 May 2025 09:51:36 GMT

I don't mind the solving with GDL part, but I would have liked to automate the process and not have to do it myself.

I also used a graphical hotspot for the height (top) and I wouldn't mind using the same for the base (bottom) but that would mess up my tiles layout

I'll try to find out more about the automatic SEO. It might be a taller order than I can handle but I would like to try

If I'm not mistaking, modifying the Wall Cutting Body.gsm should give me the result I'm looking for...given that I understand how it works haha

Re: Wall and slab accessories automatic cut

B_Migito — Tue, 03 Jun 2025 17:07:59 GMT

UPDATE (JUNE25)

Hi all,

Little update about my endeavours. I went down the rabbit hole that is the WallCuttingBody.gsm object and realized (too late I might add) that the amount of work to automate the height of my wall accessory was way over what I could do by myself.

I went back to Toper suggestion about using CUTPLANEs and added that to my object.

It might be the right (and easier) way to do it because of two things :

It helps with the creation of molding or credenza

It allows to have multiple finishes on walls

I still think that it would be cool to automate the process but I don't think it is worth doing for myself

Also. I now have to modify the whole script to add the height of the cut plane to the start of my tiles layout. Not complicated but a bit annoying

Next will be to configure the object to be able to schedule it. I don't know anything about that part so it should be fun.

That's not the topic of the discussion anymore, so I won't develop on it but, quick question for those following, is it possible to get any type of information from GDL parameters into a new properties ?

Re: Wall and slab accessories automatic cut

Barry Kelly — Wed, 04 Jun 2025 00:29:51 GMT

@B_Migito wrote:

quick question for those following, is it possible to get any type of information from GDL parameters into a new properties ?

No.

Properties can not access GDL object parameters.

Barry.