Author Topic: Scratches Generator  (Read 3060 times)

Hi there people,
I like the scratches generator look so much.
But I want to use it with Arnold materials and I don't know how to do that.
I've made a custom SBSAR file with the two scratches generator outputs (normal and greyscale) and it opens OK inside MAYA (so I can connect those outputs).
But I don't know where to connect those outputs.
If I connect the normal to the normal camera input of the shader, I don't quite get the results of Designer (MDL material).
Do you know the correct workflow for that?.
Thanks in advance.

I'd recommend downloading the Substance Plugin for Maya if you haven't already. If it's anything like the 3DS Max version, it can connect the outputs automatically. You can also take a look at the documentation page for Maya/Substance integration. It shows exactly how it all connects. I don't have any personal experience with it, so I can't help, but I hope you get something out of those links!
"Better than some, no worse than others."

Hi and thanks for your answer.
The problem is, Wes showed that node in action in a tutorial and it worked very good with MDL materials.
Arnold doesn't have such materials, so it can't be connected the way Wes does it.
My question was more like Where I connect the scratch generator to a NON MDL material, like aiStandard?
Thanks in advance.

BTW, here you can see the video I'm talking about:

The scratch generator, as you probably know, isn't a material in itself. You'd have to blend it into a material to get any results. You can do that either in Maya, or straight in Substance Designer.

Let's assume you're making the material in Maya and just want to use the scratches generator.

In Substance Designer, I would recommend you make three different outputs: Color, Mask, and Normal. Like this:

You'll use those to make different effects in Maya.
If you're making a Car Paint material like Wes, here's what I would do:

1. Connect the Normal output to Geometry / Bump Mapping (Arnold Standard Surface)
(Remember also to set the bump2D to Tangent Space Normals and to uncheck the flip Red and Green channels)

2. Connect the Color output to Base / Metalness, to make it more metallic where the scratches are. (You might want to put it through a levels equivalent in Maya first, to bring up the blacks. You don't want any plastic after all.)

3. Somehow blend the Color output with your background color (you can use the Mask output to mask where you want it,) and connect it to Base / Color. This'll give you some white in the scratched areas.

4. You might want to play with the roughness of the scratches as well. I'd assume the scratched area is less glossy so would connect the Mask output alone to the Specular / Roughness.

Again, this is just one way to do it. The scratches can affect different channels of a material in different ways, and it's up to you to determine what works best for the effect you want. I would recommend you make your entire material in Substance Designer, and connect each standard output to the corresponding AIStandard Surface input. You'll se what goes where in the documentation page.

Hope that answers your question!
"Better than some, no worse than others."

I tried all that.
BTW the most confusing thing in Wes video is where he connects the scratches in a MDL material. Since that connector is kind of hidden, I don't know what to do with it, but I guess it does more than just drive the roughness or normal map of it.
It seems Wes connect the output to a "fresnel" input of the MDL material, but I don't know how to translate that into an aiStandard shader (although it DO has that attribute).
Any tips on that?

In the tutorial Wes uses the "Scratches Generator Normal" and not the "Scratches Generator". That makes an important difference. Converting the graysclae pattern to a normal map (as suggested above) won't give a good result.

I'm not an Arnold expert but to get a similar effect you should plug this normal map on a clear coat and make sure the mip mapping (also called texture filtering) is disabled for this texture.

Edit: I looked at the doc, the aiStandard does not have a clear coat. I'd just plug the normal into the normal channel then. In the end it depends if you want to simulate a scratched metal or a scratched car paint material.
Last Edit: March 14, 2019, 11:43:13 am
Product Manager - Allegorithmic

My fault, I was refering to the scratches normal node, sorry.
aiStandard indeed does have a coat section. Would you connect it to the normals of the coat?