Out of memory error

Hi Mostapha,

Thanks to new release of Honey bee. It is actually a great job.

I have a very simple shoe box model with a window. I've tried to use all 8 CPUs of my system to run just an static simulation (just for one hour 21 June @12:00). I got an Out of memory error.

The only special thing that I used is a dielectric material.

would you please help me to figure out this problem.

Thank you in advance.

Fazel

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Permalink Reply by Mostapha Sadeghipour Roudsari on February 22, 2016 at 8:39pm

Hi Fazel,

That's a Radiance error. I found this email on Radiance mailing list but the answer is not clear. What is the definition that you're using? Is the file works fine with plastic material?

Mostapha

Permalink Reply by Sarith Subramaniam on February 22, 2016 at 9:50pm

The culprit is the dielectric material....rays tend to get "lost" inside it (or something like that). Especially if it is a solid where light is supposed to enter and leave. I used to think that it had something to do with total internal reflection. Since Radiance is a stochastic ray tracing engine, there will always be some rays that undergo total internal reflection.

I once had an online discussion with Greg Ward about this. I am pasting the relevant excerpt below:

Is there a way to debug or track a rendering processes during runtime ie to know if it will render at all ? Secondly, is there a likelihood of something like total internal reflection happening and light rays not escaping ?

Sarith (Sep 30 '15)

1

The progress reports are the best way to make sure that the renderings are progressing, which they seemed to be doing until they got killed. Even in cases where total internal reflection prevents rays escaping, the tracing will hit some limit (either -lw or -lr and setting both to 0 will give an error) to prevent an infinite loop. Believe me, if there were any infinite loops in Radiance, people would be complaining about it!

GregWard (Sep 30 '15)

So even though the calculations don't go till infinity, they might consume(or demand) more resources than available. Although the glass primitive in Radiance is also a dielectric, it isn't as resource intensive as it is assumed to be very thin and therefore optimized. Trans is another material which seems to be resource hungry.

Permalink Reply by Fazel Ganji on February 23, 2016 at 4:38am

Thank you Mostapha and Sarith

I also predicted the effect of total internal refraction inside the water layer. and I actually wanted to simulate this effect. and I am pretty sure that I need more than 6 as ab_ parameter.

what can I do?

Permalink Reply by Fazel Ganji on February 23, 2016 at 7:21am

OK, I replaced the layers of Trans material with Glass (for layers) and kept the Dielectric Water. now it is working for ab 1 to 6.

as you said Trans are very hungry :)

Permalink Reply by Sarith Subramaniam on February 23, 2016 at 2:18pm

Hi Fazel,

I would be careful about replacing materials (especially if it is for an actual project). Trans and Dielectric are two very different kinds of materials. Trans is usually used for modelling fabrics, certain types of plastics etc. while Dielectric is used for modelling glass, water etc. You can find more details here: http://radsite.lbl.gov/radiance/refer/ray.html#Materials

Sarith

Permalink Reply by Fazel Ganji on March 4, 2016 at 2:04pm

good notice. Thank you Sarith.

But I used Trans for clear ETFE foil and just replaced it with a glass (export of Optics 6 for Radiance).

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