# slightly higher irradiance values for -b 1 option

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done
something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent
component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct
< pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali

Hello Ali,

I think you are missing the "order of magnitude" (i.e. the eXXXX value
after the number) of the scientific notation. In "normal math", the numbers
you are getting are:

-b 1: 0.09245390
-b 10: 0.9045287
-b 100: 9.023538e
-b 1000: 90.39278

which are different in one order of magnitude, just as your -b input.

Best,

Germán

···

2017-04-21 8:56 GMT-03:00 Ali Fatoorechi <[email protected]>:

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done
something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent
component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct
< pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali

_______________________________________________
[email protected]

I think I expect to get at least same digits for the first few places. The
- b 10, 100, 1000 share equal first two digits that is 9 and 0(apart from
the exponent).
so I expect to see -b 1 to come as -b1 : 0.090..

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

*62 High Street*

*SteyningWest SussexBN44 3RD*

*T +44 (0)1903 879323M +44(0)7830751409*
[email protected]

···

On Fri, Apr 21, 2017 at 2:05 PM, Germán Molina Larrain <[email protected] > wrote:

Hello Ali,

I think you are missing the "order of magnitude" (i.e. the eXXXX value
after the number) of the scientific notation. In "normal math", the numbers
you are getting are:

-b 1: 0.09245390
-b 10: 0.9045287
-b 100: 9.023538e
-b 1000: 90.39278

which are different in one order of magnitude, just as your -b input.

Best,

Germán

2017-04-21 8:56 GMT-03:00 Ali Fatoorechi <[email protected]>:

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done
something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent
component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05
room.oct < pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali

_______________________________________________
[email protected]

_______________________________________________
[email protected]

Ali,
If you run the same commands multiple times, do you always get similar results? Does -b 1 always give proportionally 2% higher value than the higher orders of magnitude if you repeat the process multiple times, or does it vary?

If you change the –ad or –lw parameters do you get any different degree of consistency?

-Chris

···

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 7:57 AM

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct < pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali
____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses

Yes the posted figures are sort of avg of multiple runs.

I noticed for -b 10, 100,... options the -ad has to be increased to some x4
more to get same accuracy as -b 1.
But I am not sure if this is expected in Radiance.

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

*62 High Street*

*SteyningWest SussexBN44 3RD*

*T +44 (0)1903 879323M +44(0)7830751409 <+44%207830%20751409>*
[email protected]

···

On Fri, Apr 21, 2017 at 2:38 PM, Christopher Rush <[email protected] > wrote:

Ali,

If you run the same commands multiple times, do you always get similar
results? Does -b 1 always give proportionally 2% higher value than the
higher orders of magnitude if you repeat the process multiple times, or
does it vary?

If you change the –ad or –lw parameters do you get any different degree of
consistency?

-Chris

*From:* Ali Fatoorechi [mailto:[email protected]]
*Sent:* Friday, April 21, 2017 7:57 AM
option

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done
something wrong.

The rtrace gives roughly same irradiance figures(apart from the exponent
component) for overcast sky generated with -b 10, -b 100, -b 1000,

or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct
< pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002

-b 10: 9.045287e-001 9.045287e-001 9.045287e-001

-b 100: 9.023538e+000 9.023538e+000 9.023538e+000

-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,

Ali

____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses

_______________________________________________
[email protected]

I don’t think I’ll have the answer to your question, but to be sure we all understand… although you get more consistent values between –b 10, 100, and 1000, when you increase –ad they all converge toward the trend you would expect from –b 1?

-Chris

···

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 10:15 AM

Yes the posted figures are sort of avg of multiple runs.

I noticed for -b 10, 100,... options the -ad has to be increased to some x4 more to get same accuracy as -b 1.
But I am not sure if this is expected in Radiance.

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

62 High Street
Steyning
West Sussex
BN44 3RD
T +44 (0)1903 879323
M +44(0)7830751409<tel:+44%207830%20751409>
[email protected]<mailto:[email protected]>
www.surveymbs.com<http://www.surveymbs.com/>

On Fri, Apr 21, 2017 at 2:38 PM, Christopher Rush <[email protected]<mailto:[email protected]>> wrote:
Ali,
If you run the same commands multiple times, do you always get similar results? Does -b 1 always give proportionally 2% higher value than the higher orders of magnitude if you repeat the process multiple times, or does it vary?

If you change the –ad or –lw parameters do you get any different degree of consistency?

-Chris

From: Ali Fatoorechi [mailto:[email protected]<mailto:[email protected]>]
Sent: Friday, April 21, 2017 7:57 AM

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct < pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali

____________________________________________________________
Electronic mail messages entering and leaving Arup business
systems are scanned for acceptability of content and viruses

_______________________________________________
[email protected]<mailto:[email protected]>

Hi Ali,

I agree that this is an interesting and unexpected result. I've looked over the code, and I suspect the cause is having so many ambient samples for a small starting radiance is causing the ambient super-sampling code to hit the 1e-7 (FTINY) threshold for ignoring differences between adjacent ambient divisions.

What happens to your series when you use -as 0. I would expect the errors to go up for all brightnesses, but hopefully you will at least get the same errors for all gensky -b settings at that point. This would confirm my suspicion, and allow me to implement a fix.

Cheers,
-Greg

···

From: Christopher Rush <[email protected]>
Date: April 21, 2017 7:46:08 AM PDT

I don’t think I’ll have the answer to your question, but to be sure we all understand… although you get more consistent values between –b 10, 100, and 1000, when you increase –ad they all converge toward the trend you would expect from –b 1?

-Chris

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 10:15 AM

Yes the posted figures are sort of avg of multiple runs.

I noticed for -b 10, 100,... options the -ad has to be increased to some x4 more to get same accuracy as -b 1.
But I am not sure if this is expected in Radiance.

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

On Fri, Apr 21, 2017 at 2:38 PM, Christopher Rush <[email protected]> wrote:
Ali,
If you run the same commands multiple times, do you always get similar results? Does -b 1 always give proportionally 2% higher value than the higher orders of magnitude if you repeat the process multiple times, or does it vary?

If you change the –ad or –lw parameters do you get any different degree of consistency?

-Chris

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 7:57 AM

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done something wrong.
The rtrace gives roughly same irradiance figures(apart from the exponent component) for overcast sky generated with -b 10, -b 100, -b 1000,
or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct < pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002
-b 10: 9.045287e-001 9.045287e-001 9.045287e-001
-b 100: 9.023538e+000 9.023538e+000 9.023538e+000
-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,
Ali

Hi Greg,

True that was the cause It gives ~same results with -as 0 for all -b
values though less accurate.

thanks

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

*62 High Street*

*SteyningWest SussexBN44 3RD*

*T +44 (0)1903 879323M +44(0)7830751409 <+44%207830%20751409>*
[email protected]

···

On Fri, Apr 21, 2017 at 4:09 PM, Greg Ward <[email protected]> wrote:

Hi Ali,

I agree that this is an interesting and unexpected result. I've looked
over the code, and I suspect the cause is having so many ambient samples
for a small starting radiance is causing the ambient super-sampling code to
hit the 1e-7 (FTINY) threshold for ignoring differences between adjacent
ambient divisions.

What happens to your series when you use -as 0. I would expect the errors
to go up for all brightnesses, but hopefully you will at least get the same
errors for all gensky -b settings at that point. This would confirm my
suspicion, and allow me to implement a fix.

Cheers,
-Greg

*From: *Christopher Rush <[email protected]>

*Date: *April 21, 2017 7:46:08 AM PDT

I don’t think I’ll have the answer to your question, but to be sure we all
understand… although you get more consistent values between –b 10, 100, and
1000, when you increase –ad they all converge toward the trend you would
expect from –b 1?

-Chris

*From:* Ali Fatoorechi [mailto:[email protected]]
*Sent:* Friday, April 21, 2017 10:15 AM

Yes the posted figures are sort of avg of multiple runs.

I noticed for -b 10, 100,... options the -ad has to be increased to some
x4 more to get same accuracy as -b 1.

But I am not sure if this is expected in Radiance.

Regards,

Ali Fatoorechi

MBS Survey Software Ltd

On Fri, Apr 21, 2017 at 2:38 PM, Christopher Rush < > [email protected]> wrote:

Ali,

If you run the same commands multiple times, do you always get similar
results? Does -b 1 always give proportionally 2% higher value than the
higher orders of magnitude if you repeat the process multiple times, or
does it vary?

If you change the –ad or –lw parameters do you get any different degree of
consistency?

-Chris

*From:* Ali Fatoorechi [mailto:[email protected]]
*Sent:* Friday, April 21, 2017 7:57 AM

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done
something wrong.

The rtrace gives roughly same irradiance figures(apart from the exponent
component) for overcast sky generated with -b 10, -b 100, -b 1000,

or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct
< pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002

-b 10: 9.045287e-001 9.045287e-001 9.045287e-001

-b 100: 9.023538e+000 9.023538e+000 9.023538e+000

-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,

Ali

_______________________________________________
[email protected]

Thanks, Ali, for the quick confirmation. I just checked in a fix for the -as option to the CVS head.

Cheers,
-Greg

···

From: Ali Fatoorechi <[email protected]>
Date: April 21, 2017 8:39:32 AM PDT

Hi Greg,

True that was the cause It gives ~same results with -as 0 for all -b values though less accurate.

thanks

Regards,

Ali Fatoorechi
MBS Survey Software Ltd

On Fri, Apr 21, 2017 at 4:09 PM, Greg Ward <[email protected]> wrote:
Hi Ali,

I agree that this is an interesting and unexpected result. I've looked over the code, and I suspect the cause is having so many ambient samples for a small starting radiance is causing the ambient super-sampling code to hit the 1e-7 (FTINY) threshold for ignoring differences between adjacent ambient divisions.

What happens to your series when you use -as 0. I would expect the errors to go up for all brightnesses, but hopefully you will at least get the same errors for all gensky -b settings at that point. This would confirm my suspicion, and allow me to implement a fix.

Cheers,
-Greg

From: Christopher Rush <[email protected]>
Date: April 21, 2017 7:46:08 AM PDT

I don’t think I’ll have the answer to your question, but to be sure we all understand… although you get more consistent values between –b 10, 100, and 1000, when you increase –ad they all converge toward the trend you would expect from –b 1?

-Chris

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 10:15 AM

Yes the posted figures are sort of avg of multiple runs.

I noticed for -b 10, 100,... options the -ad has to be increased to some x4 more to get same accuracy as -b 1.

But I am not sure if this is expected in Radiance.

Regards,

Ali Fatoorechi

MBS Survey Software Ltd

On Fri, Apr 21, 2017 at 2:38 PM, Christopher Rush <[email protected]> wrote:

Ali,

If you run the same commands multiple times, do you always get similar results? Does -b 1 always give proportionally 2% higher value than the higher orders of magnitude if you repeat the process multiple times, or does it vary?

If you change the –ad or –lw parameters do you get any different degree of consistency?

-Chris

From: Ali Fatoorechi [mailto:[email protected]]
Sent: Friday, April 21, 2017 7:57 AM

Hello guys,

I am a bit struggling to make sense of numbers I get. I might have done something wrong.

The rtrace gives roughly same irradiance figures(apart from the exponent component) for overcast sky generated with -b 10, -b 100, -b 1000,

or any other power of 10, while -b 1 gives slightly higher value.

rtrace -w -h -I -ab 12 -ad 10000 0 -as 4096 -aa 0 -ar 0 -lw 1E-05 room.oct < pnt.txt

!gensky 3 21 10 -c -a 51 -o 0 -m 0 -b 1

-b 1: 9.245390e-002 9.245390e-002 9.245390e-002

-b 10: 9.045287e-001 9.045287e-001 9.045287e-001

-b 100: 9.023538e+000 9.023538e+000 9.023538e+000

-b 1000: 9.039278e+001 9.039278e+001 9.039278e+001

This is a simple room with an opening and no glazing.

Thanks,

Ali