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glass fibers

Posted: Wed May 29, 2013 7:38 pm
by daros
hi to all,
how would you model this to have a physically accurate result in maxwell?
http://www.pluglighting.com/assets/imag ... tain_2.jpg
Do you think the emitter has to be placed outside or inside of the glass fiber?
thanks for any help!

Re: glass fibers

Posted: Wed May 29, 2013 8:43 pm
by eric nixon
Hi Daros, unfortunately maxwell cant render glass which glows due to Internal reflections, tried before.. not happening. Your best bet is fakery.

If you do try, then put the emitter outside the geo. (prob need to photoshop the ambient glow.)

Re: glass fibers

Posted: Thu May 30, 2013 1:05 pm
by daros
Thanks you for the info eric!

Re: glass fibers

Posted: Thu May 30, 2013 3:15 pm
by Fernando Tella
I don't know if this is fake or accurate, but the effect is possible to achieve:

Image

This a glass cylinder (diameter=1cm and nearly 2m long) with a small plane fit inside near the top end pointing downwards.

I started with standard high grade glass and moved around 1 or 2 scattering coefficient. Emitter is around 15Watts.

The image was around SL24, but I know that's not a problem for you, Daros. Even your picture has some grain also, lol.

Re: glass fibers

Posted: Thu May 30, 2013 6:03 pm
by hatts
Eric I thought I remembered you getting some decent results when you were playing with refraction a while ago? Something with a curved glass cylinder in it?

Re: glass fibers

Posted: Thu May 30, 2013 11:41 pm
by eric nixon
EDIT; found that thread, http://www.maxwellrender.com/forum/view ... t=embedded



hmmm, I dont know where that thread is, as I remember it didnt work. Anyhow I cant see the renders on my HD, so prob got deleted (because it didnt work).

but i do remember that any amount of sss will give it a quite different look - cloudy, rather than 'glowing', the best results came from a rough glass with the emitter outside the glass, but still looked pretty crap.

Also if the emitter is inside the glass the light distribution into the scene was failing.

Basically the problem as I understand it, is that the desired glowing look, comes from almost infinite internal light bounces within smooth glass, so maxwell cant calculate that in a practical time-frame.

Re: glass fibers

Posted: Fri May 31, 2013 2:51 pm
by hatts
Yeah I think you're right, but by the end of that other thread, I'd say you had a very usable example for a majority of contexts (most people who are interested in this situation tend to indeed be talking about chandeliers & fiber optic etc.)