Arnold equivalent to Override Material?

[kristofer]

Does Arnold have an equivalent to Mental Rays Material Override and Vrays Override Mtl?

[Stephen.Blair]

Yes, Arnold has options.shader_override.

MAXtoA does not expose that Arnold parameter.

[kristofer]

Aha Thank you, so is it possible to expose options.shader_override in MaxtoA?

[RGhost77]

I wrote article how to use Arnold's operators as Override mtl feature - http://veda3d.com/override-material-for-arnold/

[abjJ53PT]

I tried following your instructions, but having a couple of issues.

First, I can't assign a material to "AOVs - AOV Shaders - Materials" that isn't already assigned to an object in the scene. I just assigned the Override_mtl to an unused object in my scene, but wondering if I've misunderstood something here.

Second, I'm getting this error when trying to render: 

[Arnold]: [ass] line 1: /Sphere001.shader: unresolved reference to '/ Override_mtl'

Didn't completely understand the override operator parameters, but thought it would work as long as I named everything correctly. Any idea what might be the problem? 

[RGhost77]

1. You can use override mtl on any object. But if no object with this material, use AOV Shader Material that will add material to scene.

2. Selection in Set Parameter node should be name of objects begins from / symbol: /Sphere001 (in your case).

Assignment Expression should be node parameter. Most geometry Max's objects in Arnold exported as polymesh node. So, shader is a polymesh parameter: shader = "/MyMaterialName".

Please check this video for to be sure what you need to do.

[abjJ53PT]

Thanks for walking me through this, I appreciate it! 

I can get it to work now. 🙂

It's not a huge problem, but 3Ds Max won't let me drag any material from the material editor over to the AOV Shader Materials, not sure why that is. 

[Anonymous]

Thanks for this!

I've gotten this to work to override all materials at render time with the override material.

I'm having an issue using this method to do a "toon" render.  I can make a "toon" shader that will make my scene look like a "sketch" (white with black outlines) If I apply this material to everything in the scene it will render correctly

but I don't want to replace all my materials, I just want to "override" temporarilly to create a black and white line drawing "sketch" to share with clients so they aren't looking at a full color/lit model in early stages. Don't want them to be reacting to a half finished rendering, just want to share a "sketch" for feedback on the camera angle and objects etc.

When I try to use this method with a "toon"  in the map slot it begins to render a preview pass and then 3ds Max crashes and closes every time.

Any ideas? or another method for temporarily overriding with a "toon" material?

In mental ray, I would drop an "ink & paint" material into the "material override" slot and hit render. It was so easy 😞

[RGhost77]

Yep, something wrong with Toon shader and AOV's slots. I don't know it is limitation or bug, 3dsmax crash.

But only working solution is use "dummy" object with assigned Toon shader which is would be source for overriding. Please check screenshot.

[Anonymous]

Thanks! that works. I added a box and applied the material to the box and positioned it off camera and it works!  good work-around

[Anonymous]

Does this need to be performed for each object in your scene? If so, it's not really an option for me as I have thousands of objects.

With MR it's was a setting under 'render set up' and it affected across the entire scene... that is what I am looking for. Does Arnold have an equivalent feature or work around? 

Thanks

Frank

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@RGhost77 wrote:

1. You can use override mtl on any object. But if no object with this material, use AOV Shader Material that will add material to scene.

2. Selection in Set Parameter node should be name of objects begins from / symbol: /Sphere001 (in your case).

Assignment Expression should be node parameter. Most geometry Max's objects in Arnold exported as polymesh node. So, shader is a polymesh parameter: shader = "/MyMaterialName".

Please check this video for to be sure what you need to do.

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[RGhost77]

Please check post #4

@Anonymous wrote:

Does this need to be performed for each object in your scene? If so, it's not really an option for me as I have thousands of objects.

With MR it's was a setting under 'render set up' and it affected across the entire scene... that is what I am looking for. Does Arnold have an equivalent feature or work around? 

Thanks

Frank

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@RGhost77 wrote:

1. You can use override mtl on any object. But if no object with this material, use AOV Shader Material that will add material to scene.

2. Selection in Set Parameter node should be name of objects begins from / symbol: /Sphere001 (in your case).

Assignment Expression should be node parameter. Most geometry Max's objects in Arnold exported as polymesh node. So, shader is a polymesh parameter: shader = "/MyMaterialName".

Please check this video for to be sure what you need to do.

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[Smallpoly]

Thank you for figuring this out! It works perfectly!

[gordo3di]

Looks like Arnold finally implemented the shaders override option in the Diagnostics > Feature Override > Shader Override section.

[MartinBeh]

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@gordo3di wrote:

Looks like Arnold finally implemented the shaders override option in the Diagnostics > Feature Override > Shader Override section.

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Well, to be fair the page https://veda3d.com/override-material-for-arnold/ already mentions this right in the beginning:

In the settings of the Arnold renderer in 3ds Max there Override material parameter can be used in Diagnostic render settings. But if you need more advanced technique, there tutorial how setup Override material trough Arnold’s operators.