Hello, thank you.
The normal is directed from the material outwards (the system node does the job well, it normalizes the vector for you) (u,v) are the parameters of orthogonal directions of the surface (bounded at 0 beginning 1 at end)
so you will have entered the 0.5.
In the code block (Com: variable) which calls the Vector class in fact and .Z (the property, Z component of the vector)
then test:
if component Z = 1, in this case it is true, otherwise it is false)
test ? action to do if true : actions to do if false ;
Filters all horizontal top faces
In fact, I should have filtered with ==-1 to take the balconies into account (worked upper surfaces, more and more like works of art in their own right) just in case.
it’s a very good reading (designscript) (How does lacing work in Design Script? - #11 by solamour)
Cordially
christian.stan