Multiple UVSets in Alembic with Vrayproxy

[ilpvfx]

Hello,
I'm trying to find a way to be able to use multiple UV sets in a vraymesh which is linked to a Alembic file. But it doesn't work... I can see the uvsets in the connection editor (see attached image), but they don't affect the object. The alembic is generated with Exocortex Crate and renders fine if it's not a vraymesh.



regards
stefan andersson

[vlado]

There is no universal way to specify multiple UV sets in Alembic files; V-Ray generally only supports the regular UVs. However, you can add V-Ray attributes to the 2D or 3D placement node for your texture and specify the name of the UV set there.

If it still does not work, would it be possible to get us an .abc file for investigation?

Best regards,
Vlado

[ilpvfx]

Hello Vlado!

Here are the steps I did

1. created a plane
2. made a new uvset (name: uvSet).
3. Added vray material and a image to the diffuse
4. Added the 2D placement node and switched it to "uvSet"
5. Exported alembic via Exocortex Crate (Ogawa) and exported it as a vraymesh.

So in my scene I have:
1 maya plane,
2 imported abc (through Exocortex)
3 vray proxy (vrmesh)
4 vray proxy (alembic)

1,2 and 3 sees the uv sets correctly and I can switch between the uv sets.
but the vray proxy that has the alembic injected can't see the extra uv set and the name of the extra uv set is named "uvmap1" and not "uvSet".

This is a little bit of a showstopper for us and it will cause a lot of problems if we need to always use vraymesh export instead of Alembic's. I really hope you have some tricks up your sleve I also attached a zip file containing the vraymesh and the alembic for you to test.

best regards
stefan andersson

[vlado]

My guess is that Exocortex writes the extra UV channel in a non-standard format that V-Ray does not recognize. I will see if there is a way for us to recognize that format though I really hate adding specific code to handle such stuff (because, if another Alembic exporter writes it in a different way, we would have to add code for it too, and there's no end to it, like it happens all the time with the velocity info...)

Best regards,
Vlado

[ilpvfx]

The reason why we are testing and starting to use Exocortex Alembic is that the built-in Maya Alembic from Autodesk doesn't support multiple uvsets. Alembic as a format supports it, but not "Autodesk Alembic". And we can also use it as a PointCache, which you also can't with "Autodesk Alembic".

regards
stefan

[vlado]

Yes, because generally Alembic doesn't support multiple UV sets The Exocortex guys came up with their own method to do it, but it doesn't mean that other Alembic readers can understand it.

Anyways, I've made a note to look into it, and we'll see how it goes.

Best regards,
Vlado

[asen.atanasov]

I'm looking into this issue right now.

Best regards,
Asen

[asen.atanasov]

We have added support for multiple uvs for tomorrow's nightly build. Please let us know is there are any issues.

Best regards,

[UdushKudush]

2 ilpvfx
select 2D placer node, add Vray attribute, and....

[ilpvfx]

Thanks! we are in the process right now of using it. I'll let you know.

regards
stefan

2 ilpvfx
select 2D placer node, add Vray attribute, and....
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