[Radiance-general] scripting genprism | no explicit holes problem

[Georg Mischler]

Jelle Feringa // EZCT / Paris wrote:

> Dear All,
>
> I'm working on a python script which I use to generate polygon description
> to describe walls, in order to automate an architectural design process.
> (building on the  http://www.dezentral.de/soft/Polygon/index.html module)
>
> Using an excellent library, all my functions are in place... the data is
> ready to be shipped to genprism... if it wasn't for No Explicit Holes
> Problem


As far as I understand, a general solution is non-trivial.
I tried something like that in AutoLisp more than ten years ago,
but I'm not sure if the code to that still exists. In any case,
it hat quite a few problems when there were multiple holes in odd
shapes.

But the best solution to this entirely depends on the way your
input data is structured. The more you know about what kinds of
polygons you're going to see, the easier it becomes.

One alternative approach would be to cut the outer polygon apart
instead of keeping it intact. Just sort the corner points of all
the holes eg. vertically, and make a horizontal cut at each
height. You need to be careful to combine equal hights (allow for
some numeric rounding error), and not to cut through tall holes
sitting next to short ones. This method should work particularly
well if the wall and hole polygons are orthogonal to each other,
which happens to often be the case in architectural models.


-schorsch

-- 
Georg Mischler  --  simulations developer  --  schorsch at schorsch com
+schorsch.com+  --  lighting design tools  --  http://www.schorsch.com/