gen_dc completes, but shows zero values at all sesnor points

radiance-daysim
1

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

2

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
[email protected]
https://www.radiance-online.org/mailman/listinfo/radiance-daysim

3

Hi Alstan,

Thank you for weighing in here (and apologies for my typo in the
heading--that's a bit embarrassing!).

Good catch on the -ab setting; that makes perfect sense as to why diffuse
contributions would not register, and the suggested values are helpful.

Frustratingly, I fear I still have an issue:
- With -ab set to 0, I receive no diffuse contribution (this is expected
per your note), *nor* do I receive a direct contribution (this is
unexpected).
- With -ab set to 2, I receive no diffuse contribution (this is unexpected)
*nor* do I receive a direct contribution (this is unexpected).
- It's only by making my roof transparent or removing the roof that I
register daylight contributions (direct and/or diffuse based on -ab setting
as you pointed out).

The building has a large window on the south facade, so even with a roof on
the building, I would expect daylight to get to at least some of the
sensors in the space.

My only thought is that my local machine is giving up or failing during the
rtrace process due to -lr set to 0, meaning, as you pointed out, that there
are no limits placed on reflections. But if it's not -ab and not -lr, what
else *might* it be? I can run some experiments if you or anyone has a guess.

Thank you again for your help!

Kerger

···

On Tue, May 9, 2017 at 3:00 PM, <[email protected] > wrote:

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Today's Topics:

   1. gen_dc completes, but shows zero values at all sesnor points
      (Kerger Truesdell)
   2. Re: gen_dc completes, but shows zero values at all sesnor
      points (J. Alstan Jakubiec)

----------------------------------------------------------------------

Message: 1
Date: Tue, 9 May 2017 10:08:39 -0400
From: Kerger Truesdell <[email protected]>
To: [email protected]
Subject: [Radiance-daysim] gen_dc completes, but shows zero values at
        all sesnor points
Message-ID:
        <CANgJyXUGVU4UjtK1o+w+v5jffs4miNuck3Pwb9iOy0QYsCZw2w
@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"

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
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------------------------------

Message: 2
Date: Tue, 9 May 2017 16:27:10 +0200
From: "J. Alstan Jakubiec" <[email protected]>
To: [email protected]
Subject: Re: [Radiance-daysim] gen_dc completes, but shows zero values
        at all sesnor points
Message-ID: <[email protected]>
Content-Type: text/plain; charset="utf-8"; Format="flowed"

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
> [email protected]
> https://www.radiance-online.org/mailman/listinfo/radiance-daysim

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