Author Topic: dubcats secret little hideout  (Read 133371 times)

2018-01-11, 22:36:26
Reply #105

dubcat

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Hey there Dubcat, how's work on those luts :D ? Can't wait to try them out. Thanks man !

Hey!

The LUTs have been ready since December, just waiting for the devs to fix the loglut loader :)

edit:

These LUTs will compress and adjust contrast. Tonemappers like ACES also change how light intensity behaves, to do this we have to change color matrix.

Here is an example made by Koola, from the Unreal 4 community.



ACES does a pretty good job at emulating how light intensity behaves, but it still has a bug with blue light. Blue turns into pink instead of cyan. fStorm has a custom matrix that correct this problem. Currently Corona does not change how light intensity behaves, so pure Red/Green/Blue will still be pure Red/Green/Blue. Stuff will look like "UE4 - Exp 0" no matter what you do.
« Last Edit: 2018-01-12, 04:34:57 by dubcat »
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2018-01-13, 00:26:08
Reply #106

serch

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The LUTs have been ready since December, just waiting for the devs to fix the loglut loader :)
u do.

Are devs actually working on the fix?

2018-01-13, 15:03:10
Reply #107

bluebox

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Thanks Dubcat :), asked if Devs are working on this topic in the daily builds topic. We'll see how it goes.

As for using LUTs only for previz grading - if something works out of the box then why overcomplicate it ;) ?

2018-01-13, 15:48:43
Reply #108

Juraj

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Instead of fixing LUT it would be better if they simply add support for OCIO. I can't trust LUT for this kind of stuff. I prefer having a trusted color management system like OCIO (works like a charm in Arnold C4D, no LUT).

LUT should just be used for pre-viz grading.

Dubcat and everyone is well aware of this, but adding full color-management has been requested for more than two years. It just doesn't feel like it will happen anytime soon, so any hack in mean-time would still be very welcome addition. Yes, LUT has certain primary use, but that doesn't mean it can't be used outside of the box for anything else.
Heck, even the main tech luminaries behind game dev like John Hable suggested LUT to be ok solution for tonemapping.

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2018-01-16, 23:51:13
Reply #109

Njen

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For sure! I tried a lot of color management LUT tests. I stopped and instead focused on a post-workflow. I just export un-tonemapped renders (openEXR) and do the rest in Davinci Resolve/Fusion or After Effect which some of them have a full color management system built in.

This is exactly my workflow as well, simple and uncomplicated to just render out linear exr's and then comp them together in Nuke, a program I 100% trust for colour management (with the right tools).
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2018-01-17, 00:51:33
Reply #110

agentdark45

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Hey there Dubcat, how's work on those luts :D ? Can't wait to try them out. Thanks man !

Hey!

The LUTs have been ready since December, just waiting for the devs to fix the loglut loader :)

edit:

These LUTs will compress and adjust contrast. Tonemappers like ACES also change how light intensity behaves, to do this we have to change color matrix.

Here is an example made by Koola, from the Unreal 4 community.

[img width=500 height=340]https://i.imgur.com/zSj6y79.jpg[img]

ACES does a pretty good job at emulating how light intensity behaves, but it still has a bug with blue light. Blue turns into pink instead of cyan. fStorm has a custom matrix that correct this problem. Currently Corona does not change how light intensity behaves, so pure Red/Green/Blue will still be pure Red/Green/Blue. Stuff will look like "UE4 - Exp 0" no matter what you do.

This is such a huge part of rendering I really don't know why we aren't looking into this with greater detail.

Please devs can we bump this up on the priority list?

How about a simple check box to unlock an "advanced tone mapper". That way all previous files render exactly the same, but for those that want to go further we have some more options (which doesn't clutter the UI by default).
Vray who?

2018-01-17, 13:59:06
Reply #111

Juraj

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How about a simple check box to unlock an "advanced tone mapper". That way all previous files render exactly the same, but for those that want to go further we have some more options (which doesn't clutter the UI by default).

Yup, full (and correct this time) filmic this way would be great.

Maybe in 2020 :- )
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2018-01-17, 17:20:16
Reply #112

Rhodesy

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Yes I think the C4D dev team is separate to the main Corona app. Also the tone mapping would quickly come to both as they use the same frame buffer window.

2018-01-19, 03:52:55
Reply #113

dubcat

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I want to state that all my posts are directed to still image architectural visualization. The stuff I post is not directed for people who use a "pipeline", like CGI film. I need to get quick and good results straight out of the frame buffer. I like to think of VFB as a photo, and then I can open the "photo" in Lightroom/CameraRaw and do the final tweaks if I want to. The logLUTs are a temporarily "hack" solution, until Corona can get a more advanced tonemapper with custom matrix. It's not a question if Corona should get a new tonemapper or not, but when. Currently I use my own custom scripts in Fusion, but I really don't want to. fStorms tonemapper is superior in every way right now. It has a shoulder, it has a toe. It adjust light intensity according to real photos. It has a custom matrix that takes care of the blue turns to pink problem. It might not be 100% photo correct, but it's not pink. I only use Corona, and it hurts to say this, but it's the truth. We are not on top of the food chain when it comes to tonemapping, and there is no reason why. Corona Team = Best Team.

edit: fixed some typos, damn you auto correct!
« Last Edit: 2018-01-19, 04:58:22 by dubcat »
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2018-01-19, 16:15:17
Reply #114

agentdark45

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I want to state that all my posts are directed to still image architectural visualization. The stuff I post is not directed for people who use a "pipeline", like CGI film. I need to get quick and good results straight out of the frame buffer. I like to think of VFB as a photo, and then I can open the "photo" in Lightroom/CameraRaw and do the final tweaks if I want to. The logLUTs are a temporarily "hack" solution, until Corona can get a more advanced tonemapper with custom matrix. It's not a question if Corona should get a new tonemapper or not, but when. Currently I use my own custom scripts in Fusion, but I really don't want to. fStorms tonemapper is superior in every way right now. It has a shoulder, it has a toe. It adjust light intensity according to real photos. It has a custom matrix that takes care of the blue turns to pink problem. It might not be 100% photo correct, but it's not pink. I only use Corona, and it hurts to say this, but it's the truth. We are not on top of the food chain when it comes to tonemapping, and there is no reason why. Corona Team = Best Team.

edit: fixed some typos, damn you auto correct!

All of the above x2

If you check the gallery, most guys on the forums are posting archviz stuff made using 3ds max. Only a small minority of Corona users are messing with Nuke e.t.c. I don't see why improving the tonemapping features of Corona to make it on par, or even surpassing the quality of F-Storm somehow detracts from the functionality for the compositing guys (it will still be there if you want it).

I'd bet my left arm that most people want an all in one solution that can produce the prettiest images out of the box, with the least amount of hassle.

This is also why I stick with Corona and don't go full into F-Storm, there are too many limitations with it despite it producing very photorealistic images.
Vray who?

2018-01-19, 19:36:18
Reply #115

bluebox

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Exactly. If you want to go pro, you still can.

As we work closely with interior designers  there is also the aspect of the images being exactly the same throught many many preview turns.
I can't imagine editing say 30 shots each time with external software, caring to maintain contrast etc. at the same level. Therefore (at least for us) getting the most straight out of VFB is very important.

2018-01-19, 22:29:12
Reply #116

zuliban

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I gave up along time ago in renders VFB i just use the lineal image as open exr and do the rest in nuke.
Still renders need small tech improvements like a correct DOF, cat eyes effect and obstruction  refraction, dof where you can see some small rainbow in some bokeh shapes and some hairs obstruction from grass in other shapes, a more correct material that preserves energy on bump and so on it.
It also would be nice to have this correct tone mapping that can mimics real world cameras and old school films.

And of course caustics... i feel nobody is looking at this anymore (corona roadmap have them)they really brings a image to life when it has enough glass or reflective surfaces.
I also have tested fstorm and i agree it feels like a real camera inside a render and create very realistic fast renders, but still i don't like the gpu low memory limitation make them really unusable for big textures or closeups maybe in some years we can have some nice 64gb cards and if miners are cool a good price range.

I also have seen some tech from Arion render and it has alot of nice features that other renders don't have like the dof obstruction and better materials i wonder why people don't use that render?
i tested it when it introduced bloom and glare before any other render then they deteached it to arionfx plugin.

2018-01-23, 00:20:50
Reply #117

snakebox

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Quote
You should try Indigo Render for caustics. The best for now, and they use MTL (Metropolis Light Transport) algorithm calculation, that are not implemented to Corona, which is why Corona caustics are nice but not the best.

I don't mean to hijack the topic, but I was pleasantly surprised by Redshifts caustics.

small test to demonstrate:
https://vimeo.com/239298771

It's still a post process like in vray I believe, but I found them much easier to use and also liked the result better. Caustics in Corona does not make sense to me, doesn't give me what I expect nor do I feel like I have any control. Hopefully that changes one day.

2018-01-23, 10:57:56
Reply #118

romullus

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I'm not Corona Team member. Everything i say, is my personal opinion only.
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2018-01-26, 01:47:22
Reply #119

dubcat

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This is from an older post I made on the forum somewhere, but I want to consolidate all the important stuff in this thread.

This is how Corona behaves today.



This is default fstorm.



These are fstorm with adjusted parameters.



fStorm at 0.99 is the same as current Corona



I just want to state again that I'm not trying to provoke, I don't like to make 1:1 comparisons between render engines. I'm posting all these findings because I think it will improve Corona as a render engine. Corona Team, you know I love you.

fStorm split the HDRi into indirect and direct pass, and I think this is the reason fStorm has different shadow values. I've talked to the Corona dev team, and they have ensured me that Corona use the correct method. So ignore the value difference, this post is about the diffuse roughness. I've made my own custom Corona to fstorm and fstorm to Corona converter, and when it comes to interior renders, diffuse roughness has a lot to say on the final render. This is a parameter that should not be overlooked by the dev team.
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