[Radiance-daysim] gen_dc completes, but shows zero values at all sesnor points

[J. Alstan Jakubiec]

Hi Kerger,

You will not receive any diffuse contributions in your model, because 
the ambient bounce setting (ab) is 0. Only direct sunlight values will 
be returned--static_system.dir.dc will show some results when sensors 
can directly see the direct solar sources. Try increasing ab to 
something larger. 2 is a good testing value, and 6 is a good value for 
high quality results. An -lr of setting of 0 means no limit; therefore, 
it should not influence your results.

 > When I changed my limit reflections parameter (-lr) to >/= 1. This 
returned both direct and diffuse coefficients.

I'm not sure how this could be with an ab setting of 0.

Best,

Alstan


On 5/9/2017 4:08 PM, Kerger Truesdell wrote:
> Hi all,
>
> Thank you in advance for any input you can share.
>
> PROBLEM:
> I cannot generate daylight coefficients using gen_dc. The program 
> /does /seem to complete successfully, creating the following files in 
> the process:
> - direct_radiance_file.tmp.rad
> - skyPatches.rad
> - static_system.dif.dc
> - static_system.dir.dc
> - DC.dc
>
> Curiously, the .dc files show zero for every sensor point! It's as if 
> rays were traced from the sensors and found no light.
>
> This would make sense in a closed box, but my geometry has a large 
> south-facing window (I'm confident in the geometry definition, the 
> materials definition, and the sky model).
>
> CONSIDERATIONS / EXCEPTIONS
> There were three occurrences where I DID manage to generate daylight 
> coefficients:
> 1. When I removed the roof. Oddly, this returned direct daylight 
> coefficients but not diffuse coefficients. I would expect to have seen 
> direct and sky diffuse represented, possibly even ground diffuse.
> 2. When I changed the roof material to glass. This, too, only returned 
> direct coefficients.
> 3. When I changed my limit reflections parameter (-lr) to >/= 1. This 
> returned both direct and diffuse coefficients.
>
> BEST GUESS
> At this point, my best guess is that rtrace_dc is somehow failing as a 
> result of my -lr setting (i.e. when it's set below 1). Is that 
> possible, or would I receive an error message?
>
> BACKGROUND INFORMATION
> Windows 10 (Intel Core i7-4600U CPU, 8GB RAM)
> Daysim 4.0 is installed
> Radiance is also installed on my machine
> PATH and RAYPATH are properly setup
>
> Thank you again for any input you can provide!
>
> #####################
> # project information
> #####################
> project_name Project
> project_directory C:\Desktop\genDCtest\
> tmp_directory C:\Desktop\genDCtest\tmp\
> bin_directory C:\DAYSIM\bin\
>
> ##################
> # site information
> ##################
> place Default
> latitude 38.1074198
> longitude 122.56970319999999
> time_zone 120.0
> site_elevation 120.0
> ground_reflectance 0.2
> wea_data_file weather.wea
> wea_data_file_units 1
> first_weekday 1
> time_step 60
> wea_data_short_file weather.wea
> wea_data_short_file_units 1
> lower_direct_threshold 2
> lower_diffuse_threshold 2
> output_units 2
>
> ######################
> # building information
> ######################
> material_file material.rad
> geometry_file geometry.rad
> sensor_file points.pts
> shading 1
> static_system \res\DC.dc \res\ILL.ill
> daylight_factor \res\DF.df
> viewpoint_file no_DGP_view_file_provided
> DC_file_format Daysim_original
>
> #####################
> # RADIANCE parameters
> #####################
> ab 0
> ad 256
> as 256
> ar 32
> aa 0.25
> lr 0
> st 1.0
> sj 0.7
> lw 0.05
> dj 0.7
> ds 0.0
> dr 0
> dp 32
> dc 0.0
> pt 0.15
>
>
> _______________________________________________
> Radiance-daysim mailing list
> Radiance-daysim at radiance-online.org
> https://www.radiance-online.org/mailman/listinfo/radiance-daysim

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