Author Topic: Light Simulation  (Read 11846 times)

2014-03-15, 20:07:15

Coronaut

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Since the dawn of man... just kidding. :D
Here is something i did in last few days, finally i got some time to do something interesting(everyone say this so i had to...)
I have made this scene(staircase to my upper floor) just for one reason, to see how real, good, etc. light simulation is in corona.
Lighting is based on IES files of existing bulbs, no portals, no fake lighting, materials and surfaces are textured as they are, so there is no fake bounces.
Render PT+HD 32PTS everything def. except Exposure comp. 2 and highlight comp. 3.5 (i have raw image that i'm planing to upload later)
Post processing in Photoshop was to add lens Flare, tighten curves and levels and small white balance adjustment and also to give lens distortion, vignetting etc. since i have used regular max cam and it sucks as it lacks bunch of stuff... Also i had to guide by FOV on camera as 17mm in any camera in max don't have slightest resemblance to real 17mm...
Also i have done PT+PT and there was no visible or significant difference(at least on my preview resolution 1200x800)
Photo was taken with canon 5d lens 17-40 f4L on 17mm and as you can see its slightly different as it has some specific distortion, no flashes, no additional lights.
Critique and all kind of stuff are more than welcome.
I would just like to thank you to developers(Steve Ballmer style) :D
I will upload other images(with time stamps, raw, more photos) until then, main dish. 
Also i am planing in doing Arion version there is 2.7.6 beta available.
Cheers!

2014-03-15, 22:32:46
Reply #1

Juraj

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So the second pic is render ? Not bad !
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2014-03-16, 09:31:36
Reply #2

Coronaut

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Yes second one is render. Thank you.
I will upload rest of it now, just to open my eyes a bit.

2014-03-16, 10:07:46
Reply #3

Coronaut

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First one is RAW. Second is White balance adjusted. I have noticed bulbs are about 400-500 kelvins higher then they actually are labeled(according to white balance)
No post processing.
Photo is sharper as it is 17mm lens while corona is FOV 64.5 and that translate in different lens size... so DOF is shallower.

2014-03-16, 10:24:16
Reply #4

DeadClown

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That's pretty cool, looks very realistic! :) I think it's less the renderer than your materials and texturing (and the amount of detail).
Any sufficiently advanced bug is indistinguishable from a feature.

2014-03-16, 10:43:47
Reply #5

Coronaut

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Thank you!

2014-03-16, 11:33:25
Reply #6

Buzzz

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Very nice image, good work realistic!

2014-03-16, 13:53:34
Reply #7

Coronaut

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Thanks!

2014-03-16, 17:58:38
Reply #8

galynskij

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Wow! Cool! Looks very good! Better than foto and more realistik!

2014-03-20, 18:20:26
Reply #9

Coronaut

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Well, this is sort of continuation of this topic
But after realizing that(see attachment 1) it is ridiculous for me to try and replicate tree as i did menage to do so with this stairs...
Let's say that it is inspired from this photo(attachment 2).
Photo was taken with canon 5d and sigma 50mm f/1.4@f/2.0 lens with one of the most beautiful bokeh and it's only second to Zeiss Normal 50mm f/1.4.
I did menage to fuck up with leaf stumps, and yes i was too lazy to correct that :( as i was thinking it wouldn't matter and that it would be hardly noticeable.
Tree is  modeled, also leaf and i didn't use any scatter plug-in(yes i know i am crazy) but i was kinda "cmon its only 100... 200... 300... hundred leafs" and that is when i realized i should use multi-scatter. And after all this self imposed mistakes i did render something at least.
Render time was 52minutes 300passes distributive render. But i should leave it for few hours...(i know... one more mistake...)
Comments and critique is more than welcome.

2014-03-20, 18:28:52
Reply #10

Ludvik Koutny

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It's really nice. Although i think it could be faster. If you have problem with DoF clarity, then you can decrease GI/AA balance value. You can also hover over the spinner to see tooltip description about why it is good to do so :)

2014-03-20, 18:34:18
Reply #11

maru

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I love the tree scheme! :D

It looks great but the tree model could be better. I'm not saying I could do it better, though. Great project, I'll be definitely following it.
Marcin Miodek | chaos-corona.com
Chaos Corona Support Team Lead | contact us

2014-03-20, 18:37:26
Reply #12

Coronaut

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Thanks!
Decrease more then 16? I find it that 16 works well for this scene, as 8 gives better(cleaner) bokeh but scene is hard on GI as everything goes trough this blinds(that are dark)+translucency(and its not that big factor in this case) i tried 32, now i will do 8 samples just to test time, but will do 800 passes.

2014-03-20, 18:54:14
Reply #13

Coronaut

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I almost forgot to mention something(as i was thinking about it while i was working)
On the day i took this photo sun was slightly occluded by clouds(if you know when sun is casting rays trough thin layer of clouds) but some portion is heavily occluded by thick cloud. I knew i wouldn't be able to replicate that. As if i am to lower intensity(as i did) sun will be bleached but it wouldn't have illuminating power and vice-verse.
It would be perfect if i could make occlusion with lets say map keep intensity but being able to adjust size(as it actually effect is similar to softbox if you leave it half open)
Sun is still hitting thin layer but doesn't stop illuminating(changing intensity that much) it more changes how that photons are bouncing and creates subtle effect of soft/hard light.
It is easier to replicate this on large scale scenes as effect tends to be less noticeable(and you can use HDRI with that lighting condition).
Best example away from waiting this specific light condition is when tree leafs or something transparent(sheets, curtains(not diffuse ones) are moving on light breeze and crating changing shadows with few hard highlights of sun rays. 
Well it would be nice to have this feature.

2014-03-20, 19:02:23
Reply #14

Ludvik Koutny

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I almost forgot to mention something(as i was thinking about it while i was working)
On the day i took this photo sun was slightly occluded by clouds(if you know when sun is casting rays trough thin layer of clouds) but some portion is heavily occluded by thick cloud. I knew i wouldn't be able to replicate that. As if i am to lower intensity(as i did) sun will be bleached but it wouldn't have illuminating power and vice-verse.
It would be perfect if i could make occlusion with lets say map keep intensity but being able to adjust size(as it actually effect is similar to softbox if you leave it half open)
Sun is still hitting thin layer but doesn't stop illuminating(changing intensity that much) it more changes how that photons are bouncing and creates subtle effect of soft/hard light.
It is easier to replicate this on large scale scenes as effect tends to be less noticeable(and you can use HDRI with that lighting condition).
Best example away from waiting this specific light condition is when tree leafs or something transparent(sheets, curtains(not diffuse ones) are moving on light breeze and crating changing shadows with few hard highlights of sun rays. 
Well it would be nice to have this feature.

There's sun size multiplier... :) It retains the power but changes how big illumination area is. It's not perfect, but it could do the trick :) And to better match the leaves to that photo. I would try feeding map that's in translucency slot through output map, and perhaps increasing output value to 1.5-2 :)