Car Swirl marks

[Xntric]

Hey guys,

Im new to corona coming from V-ray.

I'm trying to create some microscratch swirl marks on my material, like in this video

I've found this tutorial how to make it in V-ray, but can't seem to recreate it in Corona.
http://viscorbel.com/microscratches-swirl-marks-spiderwebbing-vray-tutorial/

Does anyone have clue how i can achieve this?

[Njen]

The scratches are not swirls, they are lot's of small randomly orientated marks. They just look like swirls because the light only picks up any mark that runs parallel to the hotspot. I made this really quickly in Substance painter as an example.

[Xntric]

Thanks!

however, the challenge is to make the scratches only appear in the highlights, like in the video I posted above.

In your substance example the scratches are more visible in the highlights, but still very visible on the other places :)

[sprayer]

Try this settings

Pretty simple material, base is reflective material with scratches at bump
layer1 material is chrome,
and mask for it falloff map with Fresnel

[Xntric]

Thanks! this looks pretty close to what I'm looking for!

The scratches are still a bit visible outside of the highlight.

Viscorbel solves this by making multiple layers in the blendmat with gradually weaker bump strength.
See this http://viscorbel.com/microscratches-swirl-marks-spiderwebbing-vray-tutorial/

But VrayBlend is using a Additive blend mode, while Coronalayeredmtl is not.

Any idea of how to solve this? :)

[Xntric]

I'm not trying to but my problem is that Corona does not use Additive blende mode in Coronalayered material, while VrayBlend does. With that, I have no clue on how to create the effect, but maybe someone knew of a way

[Njen]

I'm not trying to but my problem is that Corona does not use Additive blende mode in Coronalayered material, while VrayBlend does. With that, I have no clue on how to create the effect, but maybe someone knew of a way

Additive mode is not physically plausible or energy conserving in all but a few scenarios.

Think about the actual properties of the material you are trying to emulate. Those marks are micro scratches, they are essentially very shallow gouges, so you should be affecting anything which relies on redirecting the surface's shading normal. You will be able to do this properly simply by tuning in the bump (either using height and/or normal maps). If you try to fake this in any other way, you risk not having a physically plausible material that will behave strangely in some lighting scenarios.

Basically, your question is not technically a Corona question. The setup of using the right kind of micro scratch map as bump is the same for any 3D renderer.

Try this settings

Pretty simple material, base is reflective material with scratches at bump
layer1 material is chrome,
and mask for it falloff map with Fresnel

Technically speaking, the bump should be on the top layer, because that is the layer that will be scratched. The surface underneath is protected from scratches by the coat.

[Xntric]

Okay, thanks everyone!

I have somewhat come to a result, I'm not completely satisfied with it but it's okay I guess.

I've just added scratches to my bump in the clear coat of my car material and turned down bump strength a lot, like 0,05.

[Xntric]

WOW!

That's an amazing result you have gotten.

Would you mind sharing the material setup?

And as for the procedural scratches, how did you do that?