Issue with Spectral Matrix Simulation

[Hasti]

Hello,

I am relatively new to the world of Radiance and am currently learning and testing its commands. I have encountered an issue in the spectral matrix simulation section, and I would greatly appreciate any guidance on what I might be doing wrong.

As a first step, I followed the matrix simulation commands based on Subramanian’s tutorial. To ensure that I was proceeding correctly, I compared my results with Honeybee’s two-phase output (without DDS), and the results seemed consistent, suggesting that I had followed the process correctly.

However, when I attempted to extend this approach to the spectral mode, the results were significantly different from the non-spectral case. The results for month 6 (12:00 during the summer solstice) are somewhat acceptable, but for month 9 (equinox) and month 12 (winter solstice), the results appear to be completely incorrect.(Even 500 times larger. In the third row, I divided the results) The light distribution pattern itself seems reasonable.

Mat file:
void glass generic_exterior_window_vis_0.64
0
0
3 0.697576181538 0.697576181538 0.697576181538
void plastic OpaqueMaterial_f95cbb3c
0
0
5 0.2 0.2 0.2 0.0 0.0
void plastic generic_wall_0.50
0
0
5 0.5 0.5 0.5 0.0 0.0
void plastic generic_floor_0.20
0
0
5 0.2 0.2 0.2 0.0 0.0
void plastic generic_ceiling_0.80
0
0
5 0.8 0.8 0.8 0.0 0.0

Rad file:
generic_exterior_window_vis_0.64 polygon Room_1_915d0f9b…Face2_Glz0
0
0
12 0.5 0.0 0.8 3.5 0.0 0.8 3.5 0.0 2.8 0.5 0.0 2.8
generic_wall_0.50 polygon Room_1_915d0f9b…Face0
0
0
12 4.0 7.0 0.0 0.0 7.0 0.0 0.0 7.0 3.0 4.0 7.0 3.0
generic_wall_0.50 polygon Room_1_915d0f9b…Face1
0
0
12 0.0 7.0 0.0 0.0 0.0 0.0 0.0 0.0 3.0 0.0 7.0 3.0
generic_wall_0.50 polygon Room_1_915d0f9b…Face2
0
0
30 0.0 0.0 0.0 4.0 0.0 0.0 4.0 0.0 3.0 0.0 0.0 3.0 0.5 0.0 2.8 3.5 0.0 2.8 3.5 0.0 0.8 0.5 0.0 0.8 0.5 0.0 2.8 0.0 0.0 3.0
generic_wall_0.50 polygon Room_1_915d0f9b…Face3
0
0
12 4.0 0.0 0.0 4.0 7.0 0.0 4.0 7.0 3.0 4.0 0.0 3.0
generic_floor_0.20 polygon Room_1_915d0f9b…Face4
0
0
12 4.0 7.0 0.0 4.0 0.0 0.0 0.0 0.0 0.0 0.0 7.0 0.0
generic_ceiling_0.80 polygon Room_1_915d0f9b…Face5
0
0
12 4.0 7.0 3.0 0.0 7.0 3.0 0.0 0.0 3.0 4.0 0.0 3.0
OpaqueMaterial_f95cbb3c polygon Face_9d03db89
0
0
12 -27.9890382800 33.0517613807 0.0 -27.9890382800 -27.0423502206 0.0 31.8581112187 -27.0423502206 0.0 31.8581112187 33.0517613807 0.0

DC_sky:
#@rfluxmtx u=+Y h=u
void glow groundglow
0
0
4 1 1 1 0
groundglow source ground
0
0
4 0 0 -1 180
#@rfluxmtx u=+Y h=r1
void glow skyglow
0
0
4 1 1 1 0
skyglow source skydome
0
0
4 0 0 1 180

And rfluxmtx:
0. gensdaymtx -n 8 test.epw > SDM.mtx

1. oconv m.mat r.rad > model.oct
2. type p.pts | rfluxmtx -I+ -y 72 -ab 6 -ad 25000 -as 4096 -c 1 -dc 0.75 -dp 512 -dr 3 -ds 0.05 -dt 0.15 -lr 8 -lw 4e-07 -ss 1 -st 0.15 -cs 20 - dc_sky.rad -i model.oct > DC.mtx
3. rcomb -fa -h DC.mtx -m SDM.mtx -c Y > lux.mtx

[Greg_Ward]

Welcome to the forum!

Which version of Radiance you are running? (I.e., what does “rtrace -version” say?)

There was a bug in gensdaymtx that was causing solar contributions to be about 50 times normal. This was corrected in the latest patch release, available here.

If you are using this latest version, then we’ll need to dig deeper to find out what is going on. At first glance, your inputs look reasonable.

Best,
-Greg

[Greg_Ward]

If you are using the lastest patch release and getting unexpected results, there are a number of possible causes related to differences between the “gendaymtx” and “gensdaymtx” methods. The former uses a Perez sky model, whereas the latter uses a physically-based atmospheric model. They may give very different results, though a factor of 500 is difficult to explain with model variations.

I am happy to look into this further, but I need a couple of other inputs:

A) Your “p.pts” file for the illuminance measurement points
B) Your “test.epw” file
C) The commands you used for the RGB calculations that you are comparing to

Thanks,
-Greg

[Hasti]

Hello,
I’m sorry for the delay in responding.
Thank you very much. Yes, I was using an older version, and after updating, the results improved significantly.
However, there are still some errors, and the results are slightly lower compared to the 2P.

[Greg_Ward]

Hi Hasti,

I’m glad things are better than before. Small differences (up to a factor of 2) can be attributed to differences between gendaymtx and gensdaymtx, which use completely different algorithms / sky models.

Again, I would need the additional information listed in my previous reply to reproduce your comparison if you think that would be helpful.

Best,
-Greg