Vertex Color Channel for Houdini Alembic files

[gasanoff]

I'm using Vertex Color node and it works on simple meshes exported from Max,
but it does not when it comes to Alembic (exported from Houdini).
The color data is there, but mapped on a different channel

Is there a way to change the Vertex Color Channel for Alembic files in Unity
or select a proper channel in ASE somehow?

Thank you!

PS
I've posted this on SideFX forum, probably it can be done from alembic exporting
https://www.sidefx.com/forum/topic/3904 ... ost-266012

[Amplify_Borba]

Hello, thank you for getting in touch and for your support!

Are you using any plugin specifically for Alembic files?

Also, did you test this with other shaders?

[gasanoff]

I'm using Unity 2017.4.15f
with Alembic importer https://github.com/unity3d-jp/AlembicForUnity

all alembics are exported from Houdini with vertex colors Cd[r,g,b]
https://drive.google.com/open?id=1Vajdk ... MnGNQbef47

here's the static ABC file (in a zip)
https://drive.google.com/open?id=1N5aNH ... fU4lmUYXF3

I'm not sure if the color data gets into Unity,
but it's 100% visible in 3ds max (I have to specify the vertex color channel though, it's not 0, usually 1-2-3)


any idea would be appreciated
Thank you!

[Amplify_Borba]

We're not entirely sure if this might be Unity related or not, but did you try to access the Vertex Color data from the .ABC file in any other software?

[gasanoff]

Sure, It works perfectly fine with 3ds max,
There's a Vertex Color node you an apply directly to Diffuse map or any other,
but you can select the channel number (zero by default)
https://help.autodesk.com/cloudhelp/201 ... 2F1E49.png

With alembics it's usually #1-2... because color data is applied as external variable or something (a vector) with other data attached to vertices (like normals, velocity...)

looks like it's a Houdini export issue, the way it packs ABC files,
just thought there might be a way to remap the channel for vertex color somehow in ASE, because all the data is present in ABC file.

Thank you!

PS
full page about vertex color in Max
https://knowledge.autodesk.com/support/ ... B-htm.html

[gasanoff]

Quick edit:
I've posted an issue in GIT repo "AlembicForUnity",
https://github.com/unity3d-jp/AlembicFo ... issues/210
seems it's a Houdini->Alembic->VertexColor visibility issue rather than Shader related issue,

Appears ASE has nothing to do with it, as vertex color node works perfectly fine.
Issue closed?!

Thank you for being responsive anyway!
Andrew

[Amplify_Borba]

No problem Andrew, and thank you for sharing this information with us, hopefully it'll help others who might come across the same issue!

Please don't hesitate to get back in touch if you have any questions or come across any other issues.