Black Sky in Luminance Results

Does anyone have any idea why I am receiving a black color at the skylight in this point-in-time luminance simulation?


Skylight.zip (1.3 MB)Skylight.gh (1.4 MB)

The 5% VLT is deliberate. Apparently, the following simulation is done with the same parameters in DIVA and the results are very different

Is it because the sun is visible in the view?

Hi Devang, this is surprising because black is not even a color on the falsecolor palette. Can you post the HDR file and the radfiles generated prior to the Radiance run?

Thanks Sarith. I attached the files.

material_unnamed.rad (1.0 KB)
unnamed_IMG_Test.HDR (256.0 KB)
unnamed_IMG_Test@fc.HDR (133.7 KB)
unnamed_IMG_Test@fc_h.HDR (436.7 KB)
unnamed_IMG_Test@fc_cl.HDR (285.6 KB)
unnamed_IMG_Test_chkFile.HDR (250.5 KB)
unnamed_IMG_Test_noText.HDR (239.7 KB)
unnamed_IMG_Test_temp.HDR (719.2 KB)
unnamed.rad (416.3 KB)

When I change the VLT of skylight to 40% I get the following without changing any parameters
unnamed_IMG_Test%40fc

Can I add the .bat file and all the geometry and sky data referenced by it? This should mostly be in the Ladybug folder.

Thanks Sarith. Here’s the link

Hi @devang

the black color is probably because of the maskThreshold. If you set it to 0 (default 0.1) you’ll see the purple pixels back in your image. I guess you probably know it already…

Now that doesn’t explain why the skylight is so dark with VLT=0.05 while it’s bright-ish compared to the scene with VLT=0.2 (I could replicate the issue on my machine).
I’ve tried replacing the glass material with a trans but that didn’t give me an answer.

Sorry !

Thanks a lot for taking a look. Yes I did play with the maxThreshould. First time I am experiencing this.

Glad to know that you could replicate this. So My installation is fine. One thing ruled out. Thanks!

I could not recreate your error. The results appear to be fine in my installation:

By the way, the culprit appears to be your HDR itself:
unnamed_IMG_Test

I tried running the init bat commands and even they appear to render fine (given the settings):

By the way, why -ab 12?

Thanks Sarith,
What can I do to fix this HDR problem? I just tried the file on another machine. I get the same black sky.

This might be a version issue. I am using Radiance 5.2.91 dated 2018-06-20 (rcontrib -version on cmd). I am also running the perl version of falsecolor (the one shipped by NREL). Can you try a simple run to see if the parameters themselves are causing the error?

My rpict and falsecolor settings:

18:59:26 |mod:_radbase|func:call|msg:Trying to run: ['rpict', '-ab', '2', '-ad', '512', '-vf', 'view.vf', 'C:\\Users\\Sarith\\AppData\\Local\\Temp\\RAD_18_592h1dyfpp\\oconv_k93367ar.oct']

19:00:03 |mod:_radbase|func:call|msg:Trying to run: ['C:\\radiance\\perl\\bin\\perl.exe', 'c:\\radiance\\bin\\falsecolor.pl', '-i', 'test2.hdr']

(disregard the logging part!)

PS: If you need a compatible perl installation, try this: https://www.dropbox.com/sh/zvxry7eehsujq7o/AADJsN_qPEsV_9flL9Xr6GdUa?dl=0

I tried the -ab and -ad settings. The problem remains. My Radiance version would be older. I will try to use the latest version now.

Updating the Radiance version to 5.2.91bcc23df3 NREL 2018-06-20 dd not solve the problem

Can you post the getinfo on the new HDR file. On cmd just getinfo filepath.hdr

This is what I got. info.txt (7.0 KB)

Cant figure out either… your settings are similar to mine (except the view):


This might be worth escalating to the radiance forum.

Thanks for all your suggestions and responses Sarith. I will do that.