Boundary Surfaces - Substraction Problem

Hi everybody,

i was trying to substract one geometry to another (to be precise the windows from the walls) using the boundary surfaces components and i got the following error:

As you can see from the previous images, in the first one everything seems to be nice, while in the second one (with a lower scale factor) i got the error…

It seems that more i reduce the interior gometry and more i get untrimmed surfaces, which are wrongly counted as wall in my case.

I have tryed also to do it just for one wall and one window but i got the same problem.

I have to say that the geometries are built in Rhino (not through Gh) but they should be coplanar (windows and walls).

Any suggestion?

Thanks a lot in advance



Make sure input curves are flattened and are on the same plane. You can project them on the plane before trying to create the surfaces.



Thanks a lot for your answer.

Actually I have copied and pasted the surfaces (walls) in order to create the windows and then i scaled them. So i guess they are on the same plane, but i still have that issue.

Can you have a look on the file?

I attach it here

Thanks a lot


Floor_2016-08-24.3dm (1.18 MB) (804 KB)