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jason kaehler avatar image
jason kaehler asked ·

vertex color 3dsmax

hi, i'm trying to convert my old material (#26) to new Arnold material. its being driven by vertex color node . This wiring doesn't seem to work...can anyone please help? Thanks!

vertexcolor.jpg (77.5 KiB)
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Mike Samoylov avatar image
Mike Samoylov answered ·

wheel-fortroubleshoot-02.zip

It's works as expected. Please check attached scene.

p.s. In your scene you not assign Material #3 to the wheel, and Base color value must be 1.0 not 0.


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Paul Bertino avatar image
Paul Bertino answered ·

Care to expand on this explanation? I can't get vertex colors to render at all with Arnold. And there is nothing in the documentation about vertex color support.

If a model only has vertex colors then it likely doesn't have UVW coordinates, which my models do not, which I assume is why "UVW channel" OSL node is not doing anything.

Any ideas on how to fix this problem?

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Mike Samoylov avatar image
Mike Samoylov answered ·

In 2019 Max you can use OSL node "UVW Cahnnel" with Map Channel == 0 to get vertex color from object.

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Paul Bertino avatar image
Paul Bertino answered ·

OMG, thank you.

I guess I mistakenly changed the base color to zero while watching Mads' video, where he actually just changes the reflection to zero.

Thanks!!

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Paul Bertino avatar image
Paul Bertino answered ·

Awesome, thanks.

Attached is the wheel.

I did watch your video actually. Maybe I'm missing something simple.

Here is additional info on the origin of the mesh:

1) Mesh created from FARO point cloud data in CloudCompare.

2) Exported as a PLY

3) Imported into Meshlab

4) Exported as a DAE

5) Imported into 3DS Max.

I even used the vertex paint modifier and painted on top of my existing vertex colors. I still get a black render. :(

Thanks!

wheel-fortroubleshoot-01.zip


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Mads Drøschler avatar image
Mads Drøschler answered ·

please upload a section of the wheele with green paint on.
We can check if your data sits in a different channel or quickly narrow down the workflow issue.

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Paul Bertino avatar image
Paul Bertino answered ·

Thanks for the reply. I kind of understand what you're saying, but I don't know if it helps me.

I've got an imported object with vertex colors only. No UVW mapping. It displays the vertex colors fine in the viewport.

I created a shader OSL UVW CHANNEL (map channel 0) piped into the base color of an arnold standard surface.

Render in Arnold 2019 and 2020

`

Ideas? Thanks


vtexcoloredmesh.jpg (482.0 KiB)
osluvwchannel.jpg (146.7 KiB)
blackrender.jpg (66.5 KiB)
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Mads Drøschler avatar image
Mads Drøschler answered ·

Made a video, maybe this will help, atleast I show how to paint vertex colors and render them.
You can use the OSL UVW channel map and set it to the channel you export the vertex colors to, which can be any, by default 0 as already mentioned.

https://knowledge.autodesk.com/support/3ds-max/getting-started/caas/screencast/Main/Details/2a01656f-b2f5-49ba-80ce-abebcfb22faf.html

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Mike Samoylov avatar image
Mike Samoylov answered ·

Vertex color == vertex uvw coordinate, where R==U, G==V,B==W. So if you have vertex color on object that you have UVW mapping on it.
Vertex color map channel it's just custom name of UVW channel 0.


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