Ok. So I am trying to figure out if it would be possible to replace substance with Copernicus. And I am kind of at an impasse trying to figure out a good look dev environment particularly since Copernicus does not seem to handle UDIM workflow. I feel like cops is almoooost there.
Have anyone have experimented on UDIM workflow with cops?
The info out there is not that great.

while I personally havent used it, COPs since 21 support UDIMs to certain extend

if you already tried it and hitting issues, you may want to be more specific

Absolutely.
Right now I am trying to figure out how to set up a proper workflow.
The issue now is that cops has no way to preview all UDIMs at once, the way you will preview it on Painter. I will say that workflow wise Cops is closer to Designer but the potential to make it closer to painter is almost there.

Right now I am thinking a cop network to work but the scene viewer set on the stage to preview the final outputs. But as other mentions that will probably mean constantly rendering the maps before previewing. I am pretty sure this probably happens in the background in painter anyway. As multiple UDIMs is not something you want to constantly cook.

Will try to set up a test case and share. I started this post just in part to start the conversation.

Yeah, this is a use case we have on our radar but definitely didn't get completed for H21 :<

We have a lot of the pieces but are frustratingly close to being able to answer well.

In an ideal world, you'd just wire into the Preview Material COP and see your multiple UDIMs. But we weren't able to get the viewport to cook the separate UDIMs live.

So currently the "workflow" involves saving out your UDIMs to update. If they are contiguous, this can be done with the ROP Image Output with a single click; but this is not the smooth live update we desire.

Glad to see it’s in your radar. No complaints here,you guys did an amazing job with Copernicus. So thanks for the hard work.

I will find a work around then for the time being.

In the spirit to share and maybe brainstorming a better workflow here is what i came out with so far.
Basically another snag I got is that there is no global variable for current udim in Houdini (which I find crazy, definetely add one SIDEFX) so the <UDIM> does not get evaluated until the write step. This create an issue if you want to customize textures per UDIM.

So my solution is to make it on a prerender script and then just +1 the global variable pre-frame script.

I attached the example for everyone to see. In the example I just set the switch input node for testing but an option will be to add a parameter in the rop node itself or better an INDEX on the MATCH UDIM node that other nodes can reference as an id.

LAST version....
A little clean up on the code making it relative address and exporting the currently processed UDIM to an id value I called c_udim so any node in rop can use it. With the rop properly setup and the current udim value in the system the rest is up to the direction you want to take it. For full preview I can image a way to automate the map generation and remap it to a shrinked single uv layout but it will probably be better to wait for SideFX team to develop the solution.

Nicolas Heluani
Basically another snag I got is that there is no global variable for current udim in Houdini (which I find crazy, definetely add one SIDEFX) so the <UDIM> does not get evaluated until the write step. This create an issue if you want to customize textures per UDIM.

have you tried @UDIM ?
typing `@UDIM`in your Font COP works for me
and to control which UDIM to display you can use Default UDIM parameter on the COPnet which is also accessible if you are inside on the top bar on network editor

tamte

Nicolas Heluani
Basically another snag I got is that there is no global variable for current udim in Houdini (which I find crazy, definetely add one SIDEFX) so the <UDIM> does not get evaluated until the write step. This create an issue if you want to customize textures per UDIM.

have you tried @UDIM ?
typing `@UDIM`in your Font COP works for me
and to control which UDIM to display you can use Default UDIM parameter on the COPnet which is also accessible if you are inside on the top bar on network editor

Image Not Found

Of course no, feel really stupid now. I tried crap lot of stuff but not @UDIM what with the capitals?
OMG, why is the simplest things that sometimes takes us down a rabbit hole.
This kind of solves a lot of issues, this kind of solves a lot of issues I had with previewing udims. I basically needed a way to access the current udim attribute to do specific changes according to that attribute. Thank you.


EDIT: that variable seems to be very temperamental, it does not seem to work on a COP wrangle node, or other channels.arrgh.
I was trying to avoid using more variables on the geo but I think creating a UDIM value on prims is best practice for this. Thanks for all the help.