Hello,
I am working on a geometry conversion project and need to "carve" out a
hole in my wall(s) for any window(s). In lieu of actually breaking the
wall into smaller components or creating it as a large polygon wrapping
around windows I am considering using antimatter.
The 4 links below represent a building with window openings (no glass)
using antimatter to carve the holes. In these renderings I had a
polygon that defines the overall wall and then a co-planar polygon that
defines the opening. Two of the images were generated with rpict and
two with rvu. In rvu, depending on the view angle, portions of the
opening disappear. In rpict, all openings seem to be correct in size
but it seems to have a hard time determing which material to use (wall
or antimatter) creating a speckled frit look. Given that these two
surfaces do overlap, the rpict renderings make some sense as it is
similar to what I have seen with other overlapping surfaces.
My questions regarding antimatter:
1) Is the use antimatter validated? and for what, rtrace, rview, rpict?
I seem to remember the are certain situations to avoid with antimatter.
Are there alot? Should I just avoid it altogether?
2) How do you apply antimatter? The documentation I could find
discusses using antimatter applied to a "volume", and seems to indicate
that any other object in that "volume" with the modifier specified in
the antimatter definition will be invisible. How do you apply it to a
volume? From what I understand, sphere and cylinder may be the only
objects with volume in radiance. I tried applying it to a genbox that
went through my wall but that is basically applying it to 6 polygons and
I got no hole in my wall. I am worried about relying on surfaces having
to be co-planar because for any angled (off axis) planes it will be hard
to ensure the two surfaces are planar given rounding differences.
3) A hole seemed to be carved in my wall whether or not the modifier in
my antimatter definition matched my wall. From the definition, i
gathered that the modifiers listed are the only ones that will become
invisible when inside an antimatter volume, but that seems to only
sometimes be the case. Am I misunderstanding the modifier list?
4) If the rest of this is valid, what now if I put a window polygon
directly on top of the antimatter polygon? The renderings I got seemed
to take this ok. The glass modifier was not listed in the antimatter
list and it seemed to still be there intact.
Overall, I am looking for a go or no-go on this approach to carving out
holes for windows. If there are too many problems with this approach, I
will fall back on the much more time consuming process of writing an
algorithm that will create a polygon wrapped around windows - anyone
have one of those written in python?
http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfOTF4ZnRra21mdw
&hl=en
<http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfOTF4ZnRra21md
w&hl=en>
http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODlmMjI2cDZnNQ
&hl=en
<http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODlmMjI2cDZnN
Q&hl=en>
http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODdjcXA5eHNkNg
&hl=en
<http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODdjcXA5eHNkN
g&hl=en>
http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODVjd2RjNXNqcA
&hl=en
<http://docs.google.com/Doc?docid=0AcMF73k-1deIZGdkNmhja3BfODVjd2RjNXNqc
A&hl=en>
In radiance terms, here is an example of what I am trying to do for a
single wall with window. Notice, the antimatter definition lists
grey_0.00 however it seems to do a fine job punching a whole through my
grey_0.30 wall but not my trans_0.30 window.
void antimatter opening
1 grey_0.00
0
0
void plastic grey_0.30
0
0
5 0.3 0.3 0.3
0 0
void trans trans_0.30
0
0
7 0.947 0.947 0.947 0.05 0.02 0.333 0.00
grey_0.30 polygon wall
0
0
12 0 0 0
20 0 0
20 0 10
0 0 10
opening polygon hole
0
0
12 3 0 3
17 0 3
17 0 9
3 0 9
trans_0.30 polygon window
0
0
12 3 0 3
17 0 3
17 0 9
3 0 9
Thanks for the help!
Zack
···
________________________________
ZACK ROGERS PE, LEED (r) AP
INTEGRATED DESIGN ASSOCIATES, INC
437 Main Street
Longmont, CO 80501
tel: 303.848.8299, fax: 303.848.8290
www.ideasi.com <http://www.ideasi.com/>