reflector size

hi every body.i am creating a lightshelf in radiance. i have a
question.what is the minimum size that radiance considers for a reflector.
my simulations shows some mistakes when the lightshelf is less than 0.5
meter
Thank you
Sincerely
Shailan zareiy

Hi Shailan,

You need to give more details. Is this a mirrored light shelf, and what material does it use?

There is no "minimum size" for sampling in Radiance. However, depending on your scene and your rendering parameters, errors may increase as a bright, important surface gets relatively smaller and it may be necessary to adjust some parameters to compensate.

Without an image or any other information about your scene, it is impossible to be of help.

Best,
-Greg

···

From: shailan zareiy <[email protected]>
Date: November 12, 2012 9:08:36 AM PST

hi every body.i am creating a lightshelf in radiance. i have a question.what is the minimum size that radiance considers for a reflector. my simulations shows some mistakes when the lightshelf is less than 0.5 meter
Thank you
Sincerely
Shailan zareiy

Thank you Greg for your quick answer.
yes, the light shelf i simulate is a mirrored shelf.The material that i
assign to it is
void mirror Mirror3
0
0
3 .91 .91 .91
and the parameters of rendering are :
-dp=2048
-ar=32
-ms=0.063
-ds=.2
-dt=.05
-dc=.75
-dr=3
-sj=1
-st=.01
-ab=3
-aa=.1
-ad=512
-as=256
-av=0.01 0.01 0.01
-lr=12
-lw=.0005
I hope that these information is efficient

···

On Mon, Nov 12, 2012 at 9:08 PM, Greg Ward <[email protected]> wrote:

Hi Shailan,

You need to give more details. Is this a mirrored light shelf, and what
material does it use?

There is no "minimum size" for sampling in Radiance. However, depending
on your scene and your rendering parameters, errors may increase as a
bright, important surface gets relatively smaller and it may be necessary
to adjust some parameters to compensate.

Without an image or any other information about your scene, it is
impossible to be of help.

Best,
-Greg

> From: shailan zareiy <[email protected]>
> Date: November 12, 2012 9:08:36 AM PST
>
> hi every body.i am creating a lightshelf in radiance. i have a
question.what is the minimum size that radiance considers for a reflector.
my simulations shows some mistakes when the lightshelf is less than 0.5
meter
> Thank you
> Sincerely
> Shailan zareiy

_______________________________________________
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http://www.radiance-online.org/mailman/listinfo/radiance-general

Have you rendered an image? It helps a lot to tell what the source of errors might be. My first suggestion would be to increase the -ad and -as settings. Try doubling them to start.

-Greg

···

From: shailan zareiy <[email protected]>
Date: November 12, 2012 9:52:39 AM PST

Thank you Greg for your quick answer.
yes, the light shelf i simulate is a mirrored shelf.The material that i assign to it is
void mirror Mirror3
0
0
3 .91 .91 .91
and the parameters of rendering are :
-dp=2048
-ar=32
-ms=0.063
-ds=.2
-dt=.05
-dc=.75
-dr=3
-sj=1
-st=.01
-ab=3
-aa=.1
-ad=512
-as=256
-av=0.01 0.01 0.01
-lr=12
-lw=.0005
I hope that these information is efficient

On Mon, Nov 12, 2012 at 9:08 PM, Greg Ward <[email protected]> wrote:
Hi Shailan,

You need to give more details. Is this a mirrored light shelf, and what material does it use?

There is no "minimum size" for sampling in Radiance. However, depending on your scene and your rendering parameters, errors may increase as a bright, important surface gets relatively smaller and it may be necessary to adjust some parameters to compensate.

Without an image or any other information about your scene, it is impossible to be of help.

Best,
-Greg

> From: shailan zareiy <[email protected]>
> Date: November 12, 2012 9:08:36 AM PST
>
> hi every body.i am creating a lightshelf in radiance. i have a question.what is the minimum size that radiance considers for a reflector. my simulations shows some mistakes when the lightshelf is less than 0.5 meter
> Thank you
> Sincerely
> Shailan zareiy

What types of mistakes are there? Are you expecting to see direct reflection of the sun that is missing? Are you expecting higher overall values? Are you seeing a direct reflection when you were expecting it to be scattered?

You mention the error occurs when the light shelf is less than 0.5m. Is it 0.5m square? Or is it 0.5m by some longer length? Also, what are the dimensions of the room it's in? And is there a lot of additional geometry outside of the room, like the rest of a building, or even surrounding buildings? How large is everything outside the room?

···

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Dear Christopher and Greg
The problem i told is that ,for example a light shelf with width of 0.2m
increases the illumination of the zone more than a shelf with the width of
0.5 or more. but it seems that it is solved when i increase the resolution
,with increasing ad and as.thank you for your help.
i have another question that is how can i make a diffuse reflection from a
mirror material as a secondary light source
Thanks
Shailan

···

On Mon, Nov 12, 2012 at 9:50 PM, Christopher Rush <[email protected] > wrote:

What types of mistakes are there? Are you expecting to see direct
reflection of the sun that is missing? Are you expecting higher overall
values? Are you seeing a direct reflection when you were expecting it to be
scattered?****

** **

You mention the error occurs when the light shelf is less than 0.5m. Is it
0.5m square? Or is it 0.5m by some longer length? Also, what are the
dimensions of the room it’s in? And is there a lot of additional geometry
outside of the room, like the rest of a building, or even surrounding
buildings? How large is everything outside the room?****

** **

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

_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general

An example of how this is done is given in the ray/obj/virtual directory included with the Radiance auxiliary file distribution. Unfortunately, I don't have time to answer further questions on this. You'll just have to figure it out yourself.

-Greg

···

From: shailan zareiy <[email protected]>
Date: November 12, 2012 12:10:52 PM PST

Dear Christopher and Greg
The problem i told is that ,for example a light shelf with width of 0.2m increases the illumination of the zone more than a shelf with the width of 0.5 or more. but it seems that it is solved when i increase the resolution ,with increasing ad and as.thank you for your help.
i have another question that is how can i make a diffuse reflection from a mirror material as a secondary light source
Thanks
Shailan

On Mon, Nov 12, 2012 at 9:50 PM, Christopher Rush <[email protected]> wrote:
What types of mistakes are there? Are you expecting to see direct reflection of the sun that is missing? Are you expecting higher overall values? Are you seeing a direct reflection when you were expecting it to be scattered?

You mention the error occurs when the light shelf is less than 0.5m. Is it 0.5m square? Or is it 0.5m by some longer length? Also, what are the dimensions of the room it’s in? And is there a lot of additional geometry outside of the room, like the rest of a building, or even surrounding buildings? How large is everything outside the room?