[Radiance-general] AGI 32 vs Radiance

[Kera Lagios]

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 <shrikarbhave at gmail.com> 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
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