Design forum
Showing results for 
Search instead for 
Did you mean: 

Building Material Override?

Hey all,

For some reason my building materials aren't interacting right. The priority levels are set right within the Building Materials dialog box, but when I use the "Trim Elements to Roof/Shell," the walls being trimmed to the roof show their outline on the top portion of the roof. They are trimmed right, but the wall stud building material texture is different than the roof sheathing material texture, so it doesn't look right in 3D. It trimmed right when I started the model, then somewhere along the way something changed. It's like the building material priorities have been overriden.

I checked the Renovation Filter options to make sure they didn't have the, "Do not Intersect," option selected.
I checked to make sure that the Layer Priority Numbers were set to the same number.

I'm not really sure where else to look. I'm clueless. I checked everywhere. Maybe I missed something that I've already checked. Does anyone have any ideas?
>ArchiCAD 23, 6004 USA FULL
>Mac Pro (Late 2013) Macintosh HD, OS Catalina, 3.5 GHz 6-Core Intel Xeon E5 Processor, 16 GB 1866 MHz DDR3 Memory, AMD FirePro D500 3072 MB Graphics

Barry Kelly
When you are using the same building materials in the roof and walls it can get a little tricky when you have lots of skins.
Like materials (the external cladding) will trim each other allowing the inner skins to extend.
When you use a wall that has weaker external skins and the roof ply is stronger, it will cover those up.
If the roof ply is stronger than the wall inner skins, it will trim those too.
If weaker the inner wall skins will show through.

It is a bit hard to explain.
You can see in the image attached I have a vertical wall and slabs - all the same composites.
I have shown these, as slabs and walls intersect automatically (no need to trim).
You can see especially with the top 2 slabs how the trimming changes just because one of the slabs passes through the entire wall.
Probably not a good example, but you can see how things can change.

It is all a bit tricky because generally you will want the core (inside) of the wall to be stronger and the external cladding to be weaker.
But when you use the same cladding on the wall and roof it can be a bit unpredictable.
As Brazza mentioned, it is better to have 2 claddings, one for wall and one for roof.
They can look the same but give the roof a slightly higher strength so it will always cut the wall cladding.

Another tip is to use Solid Element Operations on the walls/roof.
Subtract the roof from the wall with upward extrusion.
This will trim the roof to the underside of the roof regardless of material strengths and the walls will never show through.


One of the forum moderators.
Versions 6.5 to 25
Dell XPS- i7-6700 @ 3.4Ghz, 16GB ram, GeForce GTX 960 (2GB), Windows 10
Dell Precision 3510 - i7 6820HQ @ 2.70GHz, 16GB RAM, AMD FirePro W5130M, Windows 10

View solution in original post


Didn't find the answer? Start a new discussion


Still looking?

Browse more topics

Back to forum

See latest solutions

Accepted solutions

Start a new discussion!