[Radiance-general] Modeling glare from light fixtures

[Lars O. Grobe]

Hi!
> I suppose I could build up my own mathematical representation of how the glow object should distribute its light (in effect build my own .IES file (of sorts).  Though, I truly have never done this before and I would assume there is a chance of error.
> 
> 
> Exactly. You will not only introduce some errors due to inaccurate information but you also have hardly a way to verify your model. If something is wrong with your calculation results you will have a hard time to prove it wasn't your hand made distribution. That's hardly worth it.

Maybe my view is a bit too simplifying, but, imho: I think basically, for glare, there are two cases:

1) luminaire designed without thinking about glare. Lamp directly visible. IES data does not reflect well the spatially non-uniform distribution, which is averaged over aperture area. Will probably make your client unhappy anyways in your usecase.

2) luminaire optimized to reduce glare. No direct visibility of the lamp, thus little nonuniformity over the aperture. Should be matched not all that bad by IES data.

If you really model the reflector and source, you may actually try to validate it by sampling at the directions of you IES file. Unless the data is not wrong at all, you would get the same averaged values if your model is ok. By the way, is your IES data based on measurements, or is it also the result of a simulation?

Cheers, Lars.
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