Chaos Corona Forum
Chaos Corona for 3ds Max => [Max] I need help! => Topic started by: dj_buckley on 2022-05-31, 11:30:57
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Something that's always confused me in terms of material creation is Anodised Aluminium.
In terms of the physical material - is it a metal or not?
I appreciate it's not raw metal in it's original form but as it's not a separate coating such as powder coat, or applied such as paint, does that mean it's still a metal? Is it simply enough to create an aluminium material using metalness workflow and increase the roughness to give the appearance of the anodised finish?
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Hi there, anodized aluminum is still metal, but after some chemical processes. To create this kind of material in Corona I would create aluminum and then try to play with anisotropy.
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Something that's always confused me in terms of material creation is Anodised Aluminium.
In terms of the physical material - is it a metal or not?
I appreciate it's not raw metal in it's original form but as it's not a separate coating such as powder coat, or applied such as paint, does that mean it's still a metal? Is it simply enough to create an aluminium material using metalness workflow and increase the roughness to give the appearance of the anodised finish?
I guess it depends on the type of anodizing method, but in general terms I would say it's a form of coating/thin film. As a barrier type of oxidized layer, a translucent thin film coating will be formed on the metal's surface (should be easily handled by clearcoat), with a cellular oxide layer electrolytic coloring/dying can be achieved (using tin or nickel, essentially the metal deposits get absorbed by the pores), so again clear coat should handle this with absorption coloring.
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Sounds like you know your stuff George haha, I'd love to see some examples if you have the time :)
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It's not thin film (oxidized Al visually turns white), but is coated to prevent oxidation, thus it's dyed/colored.
Resulting image started with brushed Al preset (for roughness & aniso, then complex IOR of "Al for 3D artists" was set and finally clearcoat absorption color was picked from referential image...
(http://)Basically, simple colored metal would do good enough.
;)
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Interesting, visually it's a pretty straight forward material, I just wondered what the physically correct setup would be. Interesting to see the different takes
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Sounds like you know your stuff George haha, I'd love to see some examples if you have the time :)
I hope this will help clarify my approach, as mentioned previously it depends on the method used, for electrolytic coloring with metal salts being used as colorants your coating/film will consist of metal coloring (limited to colors with yellow tints, blacks, bronze or gold) deposited in the oxide pores.
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=36835.0;attach=166879;image)
As to how to approach this with Corona Physical and make it as accurate as possible, you can start with an aluminium foil preset as base from the Basic options > Apply preset of Corona Physical material, these presets are all made using Complex IOR for metals, so their parameters are physically accurate. You will need to create a Corona Layered Mtl. and set your base as the aluminium foil, for coating you will need to create a metal material as an electrolytic dye and apply it in your layer slot, you can either "eye-ball" it or use complex IOR to get more physically accurate results (please refer to the guide here: https://support.chaos.com/hc/en-us/articles/4528348723985-How-to-use-ComplexIOR-for-CoronaPhysicalMtl-) (do note you can do this with clearcoat as well but you are missing out on complex IOR properties of the coating).
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=36835.0;attach=166881;image)
For organic or inorganic dyeing/coloring that mostly consists of chemical dyes, you will need to create a Corona Physical Mtl. with an aluminium foil preset as base from the Basic options > Apply preset of Corona Physical material. Enable your Clearcoat layer set the corresponding IOR of the coloring agent that's being used (f.e. acrylic), and simply allocate the color of your choosing. For both cases surface irregularities might be bound in both the coated material but also the base depending on what you want to achieve as for color-intensity/saturation it really depends on the process. I am attaching some really basic examples/images!
(https://forum.corona-renderer.com/index.php?action=dlattach;topic=36835.0;attach=166883;image)
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Awesome thanks George. I found this page which has a nice explanatory diagram too. I was actually thinking a much more matte type look, almost but NOT the same as the powder coated look used on Window Frames etc) but the process still stands and it would be the coating layer that gets 'rougher' I suppose.
https://nulinewindows.com.au/blog/anodising-aluminium
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Awesome thanks George. I found this page which has a nice explanatory diagram too. I was actually thinking a much more matte type look, almost but NOT the same as the powder coated look used on Window Frames etc) but the process still stands and it would be the coating layer that gets 'rougher' I suppose.
https://nulinewindows.com.au/blog/anodising-aluminium
Hi again, nice presentation on the link, and yeah indeed having roughness to both layers might be the way to approach this, with coating layer seemingly being less strong.