Magic Area Light

Discussion related to the Engine functionality, implementations and API.
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Sharlybg
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Magic Area Light

Post by Sharlybg » Wed Jun 13, 2018 2:30 pm

Please read it until the end if you can ;)

Recently i was doing some test to find a way to deeply reduce render time in Interior rendering. So i tried to find what slow down interior render. The principle is quite simple :

If light source is easy to find , not hiden and bouncing through cumbersome geometry then the render is bloodly fast. This is why outdoor are so fast. So i decied to create a realistic kitchen lit by AREA light only. And i got fast render and decide to compare with HDR lighting :



AREA 1024 samples 3.12mn ( 1080 Ti)
Area 3.12mn.jpg


HDR 1024 samples 3.0mn ( 1080 Ti)
HDR 3.0mn.jpg

AREA is by far cleanner but HDR is the most natural/realistic. So i wonder how we can combine the best of theses to ways. I already know about Portals. And while reading an Fstorm tutorial i found this :

https://www.behance.net/gallery/4598523 ... m-Tutorial
Eng.
As Vray or Corona, Fstorm has a portal system. He is very used to illuminate interiors in order to collect many more photons.
In Fstorm, It just to create a plane, glued of the borders of your wall at the level of the framing of your windows.
Be careful to orient the normal of your plane pointed inside. Then apply a "FstormPortal" material. Then you can manage the power of your portal from the material.
For my project, I used a portal with 5 power.


I said to myself maybe portals power in Fstorm is like importance in Luxcore :?: and i feel like not the case.

Also bertrand said this while testing Fstorm :

http://bertrand-benoit.com/blog/westkaai-via-fstorm/
I initially found FStorm to be slow for a GPU renderer when rendering interiors, but this was before I placed portals in my windows. This sped things up considerably. It’s been years since I had to work with portals in any renderer, so it felt strange to go back to them. But why not. They certainly work well here.
I could generate final 2K images in about an hour each on a single 1080ti.
When you add to this that Fstorm don't support any form of Denoiser.

So i decied to see if we can't make an Area light to behave like HDRi in real life and Found this :
An ITALIAN scientist create a wonderful artificial light panel that mimic real daylight sun. Strangely they name is CoeLux :lol:

http://www.coelux.com/


https://youtu.be/aJ4TJ4-kkDw

CoeLux Residential anteprima.jpg
CoeLux-Hospitality-and-Recreation-areas-lighting.jpg
CoeLux-Healthcare.jpg
My question is : Is it possible to :

1/ Create a numeric version of coelux panel ?

2/ is it possible that this speed up rendering ?
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Sharlybg
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Re: Magic Area Light

Post by Sharlybg » Thu Jun 14, 2018 7:57 pm

:?
Sorry guys i know we are progressing in LC method but i just got this idea and really want to know if it is viable.
Just want to know if this idea can work.

Please if you can tell me ;)
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B.Y.O.B.
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Re: Magic Area Light

Post by B.Y.O.B. » Thu Jun 14, 2018 8:16 pm

To be honest I don't see how the magic area light would be different from a portal/visibility map.

Portals and the visibility map can only improve direct light sampling. Try to do the same test with path depth 1 so you compare only the noise in the direct light contribution.
I have the suspicion that the noise in your testscene comes from something different.

You can also use the direct/indirect AOVs for comparing the noise of direct/indirect light.
In this example you can see that the direct diffuse and direct glossy (top mid and top right) are mostly noise-free, while the indirect diffuse and indirect glossy (buttom mid and bottom right) are still noisy and show fireflies.
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Sharlybg
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Re: Magic Area Light

Post by Sharlybg » Fri Jun 15, 2018 9:48 am

To be honest I don't see how the magic area light would be different from a portal/visibility map.

Portals and the visibility map can only improve direct light sampling
thanks for your answer ! You're probably right. Maybe my idea is worse ;) . But really want to understand. The main thing that make me ask is:

# 1 It is clear that Area light and Hdri spread light defferently. So want to know if we can artificialy manipulate Rays comming from An Area light(I mean ramdomly change rays color temperature and spreading angle) to behave light HDRi.
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Re: Magic Area Light

Post by Sharlybg » Wed Jul 25, 2018 1:16 pm

How this is possible just to understand.

A portal surface capable of emitting so much light like this in the void while the HDR source stay much more dark :
page4-2-1.jpg
https://fstormrender.ru/manual/fstorm-portal-material/
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