Author Topic: Fake metals in physical material  (Read 2677 times)

2022-07-15, 12:49:13

davetwo

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I've been using the Physical material more and more. But in my work (product design, packaging, and also automtive) there are a lot of non-metal metals.
Ie. metal effect plastics, silver spraypaints, foil block print etc. etc.

What is the intended workflow with these in the new metalness workflow? I find increasing the IOR value in non-metal insufficient (too dark). And the physical metal too bright.

Any thoughts?

2022-07-15, 21:12:48
Reply #1

burnin

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If not yet, click on Corona's "Convert scene" button. Does just fine with most "high-IOR-Legacy-metals".

   

2022-07-16, 10:14:37
Reply #2

davetwo

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Sorry, I think I wasnt clear - I'm refering to creating metal-look materials which are not real metals - for example plastic with a silver spraypaint finish.

There is no slider or float value for the metalness setting - it's either on or off. So I'm wondering what the 'correct' workflow for this in Physical. (Using the Legacy Material you could just use 6-20 in the IOR value and that worked fine - but it's not an option in the new Physical Material.)


2022-07-16, 10:39:00
Reply #3

John_Do

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There is no correct workflow per se, it's all fake.

Regarding the metalness channel in the Physical, you can use a Color shader in the texture slot, then you'll be able to tweak the metallic strength.

2022-07-16, 14:31:15
Reply #4

burnin

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Absurd, but true. We are all "fakes". It just depends on where one finds own meaning and truth.

"Un-real metal" has layer consisting of metal or metallic particles, flakes (feature request!)...
Regarding physical laws, knowing periodic table of chemical elements is fundamental for reproducing visual properties of those to ones best artistic abilities. Rightly we're reminded for making "fakes", since Corona is not "predictive rendering engine". Still, it offer tools with which anyone, using certain techniques (use complex IOR for metals), can achieve visually pleasing and believable results (almost indistinguishable from photographs).


If it's "correct", depends on "your warlord" :p

Enjoy :D
« Last Edit: 2022-07-16, 14:36:55 by burnin »

2022-07-17, 19:57:51
Reply #5

BLADE

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"Regarding physical laws, knowing periodic table of chemical elements is fundamental for reproducing visual properties of those to ones best artistic abilities"

Thank you for your humor in these dark times.
It's not the end of the world. But you can see it from here.
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2022-07-18, 15:03:58
Reply #6

burnin

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For a good spirit, always a pleasure.  Tho, there's some truth in that joke ;)
Shell we take it further? Do you have any specific material in mind? Any image reference? A whole set... :D


Take care

2022-07-21, 11:22:45
Reply #7

Stefan-L

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what i do (if not use the legacy mat):

1) use a grey scale color in metalness texture slor, to reduce the metal effect. for plastic metals etc this often helps(like only 50% metal effect)
2) reduce the edge color value, this is very bright as default, reducing it also often helps i think

that said i still miss a reflection color or value at least, as vray 5/6 has it. i think it would  not make the material less physical, but better to use (it isnt now either) and more compatible to industry standards-

2022-07-21, 13:05:15
Reply #8

Nejc Kilar

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Ideally with the Physical material you'd approach things like you would in a physical sense. Is the material a non-oxidized pure metal material? Go with metal. Is it a painted metal? Then paint is a non-metal material applied on top of a metal material and so you're basically recreating just that top non-metal paint layer.

If you've got paint on top of a metal material but the paint is sort of incompletely applied and you can see the actual underlying metal? Using a black and white mask as a metalness map could be the way to go.
Alternatively (and I prefer this workflow myself) you can also use the layered material, put the metal material as a base and a painted material on top then just mask everything with a nice punchy black and white mask. I prefer this approach because you're thinking about layers, just like you would in the real world and you have easier control over both materials. It might be a bit slower to render though.

To control the reflection strength of your metal materials you can play with the base color value and if you're into them details then tweaking the edge color is also important. In both cases I'd try to compare my material to the real world reference as I'm tuning things.

One quick note, technically using values between 0% and 100% for the metalness is physically incorrect. If you're using in between values you're basically just blending between a metal and a non-metal material which... Is not physical. Can be useful though so that's why we've left it in. Also, if you're using maps for the metalness make sure they're also either fully white or fully black because again, in between values... Not so physical :)

Not sure if the above helps but hey, that's why we've got the forums here to discuss things.
Nejc Kilar | chaos-corona.com
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2022-07-23, 02:44:41
Reply #9

burnin

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Regarding all, I think that this procedural VRay's CarPaintMtl, would be really beneficial in Corona. :D
eg. (imagine adding a bit of roughness on coating or "driving" it w/ 'flakes')

2022-07-23, 10:43:05
Reply #10

romullus

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  • Let's move this topic, shall we?
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By the way, dedicated car paint shader currently is the only one feature that has zero votes in the most wanted features poll, so if you'd like to change that, make sure to visit that poll here: https://forum.corona-renderer.com/index.php?topic=96.0
I'm not Corona Team member. Everything i say, is my personal opinion only.
My Models | My Videos | My Pictures

2022-07-24, 20:17:21
Reply #11

burnin

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By the look of that list, if Corona devs intend to follow it, we're up for bug inflation and recession afterwards :p

// I choose to be part of solution instead :)
Some time ago, I already made a custom physical, fully procedural one w/ some extra stuff to suit my needs ;)
Anyways, here are few renders of it, as a 'proof of concept' for "metallic-plastic" use/look.