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Start with a default Arion BSDF material.

BRDF attributes
Fresnel IOR 1.51 0.0
Falloff 46.5 16
Color
Edgetint
Roughness | % 100
Bump | % 10

 

Carpaint material are slightly metallic, so we will need to use metal-like parameters such as a relatively high Fresnel IOR and an average Roughness.

BRDF attributes
Fresnel IOR 5 0.0
Falloff 46.5 16
Color
Edgetint
Roughness | % 30
Bump | % 10

 

Next step is to add a layer of lacquer, through the use of Coating.
Carpaint lacquer is very shiny, so don't be afraid to use bright Color and Edgetint colors. Lower the Roughness as well. We have used a value of 1%, because we hate perfect, mirror-like reflections and so should you.
In this example, we have used respectively RGB 200,200,200 and 250,250,250.

Coatings
Enable
Thin-film
Fresnel IOR 1.51
Color
Edgetint
Roughness | % 1
Thickness | nm 250 1000

 

Now this would do a perfectly viable gray carpaint for a car of the famous three branches manufacturer, but we should try some colors.

In this example we have started with our now classic RandomControl red, used in the Color channel of the BRDF attributes then copied to the Edgetint channel in a lighter shade.
Respectively RGB 182,32,2 and 220,110,90. 

BRDF attributes
Fresnel IOR 5 0.0
Falloff 46.5 16
Color
Edgetint
Roughness | % 30
Bump | % 10

 

Although Arion Render v3 features a Flakes texture internally, we will now add metallic flakes using a traditional method: A noise texture (procedural in our case but a bitmap will do).

We connect this noise texture into the BRDF properties Roughness channel.

Note that originally we used a Roughness value of 30%, which correspond to approximately an RGB color of 76,76,76, so the noise texture should be generated with shades of gray a bit below and a bit above that value.
In our example we have generated the noise texture using gray shades of RGB 48,48,48 and 96,96,96, as once textured the Roughness value is entirely ignored and only the texture colors are used by Arion.

The tiling of the texture has been kept intentionally low enough so the effect is clearly visible on this page.

BRDF attributes
Fresnel IOR 5 0.0
Falloff 46.5 16
Color
Edgetint
Roughness | % 30
Bump | % 10

 

This is it for this very basic carpaint tutorial, it looks good enough if not seen from too close. In another tutorial we will detail the creation of more believable flakes.

For now, let's see how we can create funky candy color carpaints easily.

Change the Color and Edgetint colors to very different shades, such as blue and magenta.

BRDF attributes
Fresnel IOR 5 0.0
Falloff 46.5 16
Color
Edgetint
Roughness | % 30
Bump | % 10

 

This is cool but there is too much magenta and not enough blue to my taste.

We can change that by using the Falloff parameter, which we have seen in the Fabric tutorial and that allows to define arbitrary Fresnel IOR values for front-facing and grazing angles parts of the object.

You should play with both values to get the effect you want and understand how it works, but for this tutorial we have used the values 1.5 and 5.0.

BRDF attributes
Fresnel IOR 5 0.0
Falloff 1.5 5.0
Color
Edgetint
Roughness | % 30
Bump | % 10

 

Now by simply changing the Color and Edgetint and editing the Falloff parameters, you can create many different candy-color carpaints.

 

 

 

 

 

 

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