[Radiance-general] DGP studies: image size

[Randolph M. Fritz]

Thanks. That helps.

-- 
Randolph M. Fritz, Lighting Design and Simulation
+1 206 659-8617 || rmfritz3 at gmail.com

On Tue, Mar 8, 2016 at 1:38 AM, Jan Wienold <jan.wienold at epfl.ch> wrote:

> Hi Randolph,
>
> as the question is general, the clear answer is no - this cannot be
> recommended in general. Just imagine having a 180 degree fish eye resolving
> the sun (or reflection of it)  with 0.5 degree and having only 500x500
> pixels. We made this recommendation of 800x800 10 years ago, when a)
> evalglare was in its first version (in the meanwhile I optimized the code
> which results in average to 30% time saving compared to the first versions)
> b) computer power was less. Nowadays I recommend 1000x1000, especially when
> dealing with fabrics/translucent materials with a certain peak transmission.
> Another example: Imagine you want to do a electric lighting analysis with
> small emitting surfaces (e.g. bunch of single LEDs) of high luminances. In
> that case you really want to resolve the glare sources not only with 1
> pixel each.
>
> But on the other hand, there are also many cases, where you are totally
> fine with 500x500, when your potential glare sources are rather large.
>
> I'm currently performing a study including images from several groups - we
> are having more than 1000 images and I would say in average an evalglare
> run was about 7s per image (using 1000x1000). The more glare sources are
> found in the image, the longer it takes (this has to do with the combining
> the "glare source pixel" to glare sources). So for a scene with a large
> amount of glare sources you might end up with 3-4min per image.
>
> Jan
>
>
>
>
> On 08/03/16 03:19, Randolph M. Fritz wrote:
>
> The original paper recommends 800x800 images for glare studies. Anyone
> have a feeling for how hard and fast that is? Would the canonical 500x500
> be enough?
>
> --
> Randolph M. Fritz, Lighting Design and Simulation
> +1 206 659-8617 || <rmfritz3 at gmail.com>rmfritz3 at gmail.com
>
>
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> --
> Dr.-Ing.  Jan Wienold
> Ecole Polytechnique Fédérale de Lausanne (EPFL)
> EPFL ENAC IA LIPID
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