Hello All,
I have been put in an unusual situation of convincing someone that radiance
is better and more scientifically accurate at simulating a daylighting
scene which includes large application of translucent glazing. I haven't
used AGI 32 at all to understand the nuances myself.
Could someone please provide salient features comparing the two and/or
point me to the correct resources? What I have found online hasn't been
convincing. May be I am not searching in the right place.
So that you know, the audience is not technically sound. But understands
light well in the architectural context.
Thanks in advance,
Shri
Hi Shri,
Perhaps you know this already, but the major difference between AGI
and Radiance is that AGI uses radiosity rather than raytracing to
calculate light, and therefore does not calculate specularity or
specular light transmission. You can raytrace individual views in AGI,
but that applies Ray tracing to the direct component only and it does
not affect any calculated point grids. Qualitatively, visualizations
are less true to life. Ability to control your calculation parameters
in AGI is also limited.
Another limitation with AGI is the ability to define complex
materials. In general the parameters are limited to tramsittance or
transparency and color. There is an option to add a texture, but I
think these are just image maps, although I would have to check. If
you are planning on using a complex definition for your materials, AGI
does not support that.
Lastly, AGI doesn't support climate-based metrics/annual calculations or DGP.
I have heard that there are several papers and studies out there that
try to compare AGI, Radiance, and other softwares, but I don't have
any specific reference to give you.
None of this is to say that AGI is not accurate, especially within
it's given capabilities, and in your case if the translucent material
you are using is 100% diffusing, and you do not need to address
specularity, daylight autonomy or DGP, you would likely get reasonable
results as far as the light transmission through the glazing. But in
the end, Radiance has much greater capacity to simulate daylight,
glare, materials, etc.
I hope that helps,
Kera
···
Sent from my iPhone
On Mar 12, 2015, at 4:37 PM, Shrikar Bhave <[email protected]> wrote:
Hello All,
I have been put in an unusual situation of convincing someone that radiance is better and more scientifically accurate at simulating a daylighting scene which includes large application of translucent glazing. I haven't used AGI 32 at all to understand the nuances myself.
Could someone please provide salient features comparing the two and/or point me to the correct resources? What I have found online hasn't been convincing. May be I am not searching in the right place.
So that you know, the audience is not technically sound. But understands light well in the architectural context.
Thanks in advance,
Shri
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general
Wow Kera, all that info, and from your iPhone?! Impressive. Kera hit all
the points, I think. I would only add that I think AGI *can* produce
pretty convincing images, within the limitations of the radiosity approach
(i.e. no true specular reflection model). In fact the brains behind AGI
(Ian Ashdown) recently contributed to a thread on a LinkedIn forum about
how AGI is the only commercial lighting simulation tool that can render
chromatic adaptation (constancy), which is pretty damned impressive and
goes along way toward "true to life" renderings.
Shri, your specific case of wanting accuracy in the translucent realm is
what finally drove me from Radiance dabbler to Radiance user many moons
ago. Since then however, AGI has matured quite a bit. In my book, the
inability to do climate based simulations and metrics is a non-starter,
though.
- Rob
···
On 3/13/15, 9:19 AM, "Kera Lagios" <[email protected]> wrote:
Hi Shri,
Perhaps you know this already, but the major difference between AGI
and Radiance is that AGI uses radiosity rather than raytracing to
calculate light, and therefore does not calculate specularity or
specular light transmission. You can raytrace individual views in AGI,
but that applies Ray tracing to the direct component only and it does
not affect any calculated point grids. Qualitatively, visualizations
are less true to life. Ability to control your calculation parameters
in AGI is also limited.
Another limitation with AGI is the ability to define complex
materials. In general the parameters are limited to tramsittance or
transparency and color. There is an option to add a texture, but I
think these are just image maps, although I would have to check. If
you are planning on using a complex definition for your materials, AGI
does not support that.
Lastly, AGI doesn't support climate-based metrics/annual calculations or
DGP.
I have heard that there are several papers and studies out there that
try to compare AGI, Radiance, and other softwares, but I don't have
any specific reference to give you.
None of this is to say that AGI is not accurate, especially within
it's given capabilities, and in your case if the translucent material
you are using is 100% diffusing, and you do not need to address
specularity, daylight autonomy or DGP, you would likely get reasonable
results as far as the light transmission through the glazing. But in
the end, Radiance has much greater capacity to simulate daylight,
glare, materials, etc.
I hope that helps,
Kera
Sent from my iPhone
On Mar 12, 2015, at 4:37 PM, Shrikar Bhave <[email protected]> >>wrote:
Hello All,
I have been put in an unusual situation of convincing someone that
radiance is better and more scientifically accurate at simulating a
daylighting scene which includes large application of translucent
glazing. I haven't used AGI 32 at all to understand the nuances myself.
Could someone please provide salient features comparing the two and/or
point me to the correct resources? What I have found online hasn't been
convincing. May be I am not searching in the right place.
So that you know, the audience is not technically sound. But
understands light well in the architectural context.
Thanks in advance,
Shri
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general
Hi Kera and Rob,
Thanks a lot both for your input! I was only aware of the two items.
1. Radiosity vs. Raytracing
2. Limitations in modeling specular reflection
Good to know the details.
Shri
···
On Fri, Mar 13, 2015 at 11:41 AM, Guglielmetti, Robert < [email protected]> wrote:
Wow Kera, all that info, and from your iPhone?! Impressive. Kera hit all
the points, I think. I would only add that I think AGI *can* produce
pretty convincing images, within the limitations of the radiosity approach
(i.e. no true specular reflection model). In fact the brains behind AGI
(Ian Ashdown) recently contributed to a thread on a LinkedIn forum about
how AGI is the only commercial lighting simulation tool that can render
chromatic adaptation (constancy), which is pretty damned impressive and
goes along way toward "true to life" renderings.
Shri, your specific case of wanting accuracy in the translucent realm is
what finally drove me from Radiance dabbler to Radiance user many moons
ago. Since then however, AGI has matured quite a bit. In my book, the
inability to do climate based simulations and metrics is a non-starter,
though.
- Rob
On 3/13/15, 9:19 AM, "Kera Lagios" <[email protected]> wrote:
>Hi Shri,
>
>Perhaps you know this already, but the major difference between AGI
>and Radiance is that AGI uses radiosity rather than raytracing to
>calculate light, and therefore does not calculate specularity or
>specular light transmission. You can raytrace individual views in AGI,
>but that applies Ray tracing to the direct component only and it does
>not affect any calculated point grids. Qualitatively, visualizations
>are less true to life. Ability to control your calculation parameters
>in AGI is also limited.
>
>Another limitation with AGI is the ability to define complex
>materials. In general the parameters are limited to tramsittance or
>transparency and color. There is an option to add a texture, but I
>think these are just image maps, although I would have to check. If
>you are planning on using a complex definition for your materials, AGI
>does not support that.
>
>Lastly, AGI doesn't support climate-based metrics/annual calculations or
>DGP.
>
>I have heard that there are several papers and studies out there that
>try to compare AGI, Radiance, and other softwares, but I don't have
>any specific reference to give you.
>
>None of this is to say that AGI is not accurate, especially within
>it's given capabilities, and in your case if the translucent material
>you are using is 100% diffusing, and you do not need to address
>specularity, daylight autonomy or DGP, you would likely get reasonable
>results as far as the light transmission through the glazing. But in
>the end, Radiance has much greater capacity to simulate daylight,
>glare, materials, etc.
>
>I hope that helps,
>Kera
>
>
>Sent from my iPhone
>
>> On Mar 12, 2015, at 4:37 PM, Shrikar Bhave <[email protected]> > >>wrote:
>>
>> Hello All,
>> I have been put in an unusual situation of convincing someone that
>>radiance is better and more scientifically accurate at simulating a
>>daylighting scene which includes large application of translucent
>>glazing. I haven't used AGI 32 at all to understand the nuances myself.
>>
>> Could someone please provide salient features comparing the two and/or
>>point me to the correct resources? What I have found online hasn't been
>>convincing. May be I am not searching in the right place.
>>
>> So that you know, the audience is not technically sound. But
>>understands light well in the architectural context.
>>
>> Thanks in advance,
>>
>> Shri
>> _______________________________________________
>> Radiance-general mailing list
>> [email protected]
>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>
>_______________________________________________
>Radiance-general mailing list
>[email protected]
>http://www.radiance-online.org/mailman/listinfo/radiance-general
_______________________________________________
Radiance-general mailing list
[email protected]
http://www.radiance-online.org/mailman/listinfo/radiance-general