I've checked through the thread to find an answer to my question, but I couldn't find an helpfull one. Therefore I come back to you with the question.
Inserting an invisible box from the file box_invisible.zip works fine for rectangular windows, but when I use a triangle from the file triangle-invisible.zip, the hole remains opaque, not allowing to see through the wall as expected (see picture hereafter).
I want to use this to represent a wood beam under the roof starting from a wall.
Could you please show me a way to realize this.
Thanks a lot for your help and congratulations for your remarkable program.
[:-/]