UDIM Cage Bake Not Working

[JabbaTheNut]

When I do a UDIM bake with a low and high poly, but without a cage, all is fine.  However, when I do the same UDIM bake with a cage (e.g., the low poly pushed out a bit), the bake does not respect the UDIMs. The caged UDIM bake does all bakes in 0-1 UV space as though there were no UDIMs. Each bake multiplies on top of the previous bakes.  Is this a known bug?

[Vincent Gault]

hey, the cage is not unique per texture set, which explains why it it not feasible.

[JabbaTheNut]

Thanks for the response Vincent.

That is interesting.  How then does one do UDIM bakes with a cage?  I believe there is the option to use only one cage.

[JabbaTheNut]

Hi Vincent,

I was thinking a bit about your response...

When I use a single .FBX file which contains my UDIM'd mesh, it bakes just fine without a cage.  In other words, the single .FBX is not unique to each texture set.  It bakes to each respective UDIM appropriately from the single file.

When I use a cage .FBX file with the same mesh, adjusted to be a UDIM'd cage, the bakes fall apart.

I am not sure I agree that it has something to do with the file not being unique to the texture set.

[Froyok]

The cage is loaded in the common parameters of the baker, this means the cage file will be used for each texture set when baking. Since we match a cage mesh based on the UVs of the low poly mesh and the cage, it means you can't have cages from the other texture sets inside one big cage FBX file. You will have to change the cage file and bake each texture individually.

[JabbaTheNut]

OK.  I appreciate the response.

I hope the UDIM cage bake process will change soon.  The current process makes UDIM baking a bit difficult as I have to break the bakes out as though they were individual objects with UVs in the 0-1 space.

I know UDIM support is new for Substance and I am excited that Allegorithmic is implementing it.

[yarogor]

Have same issue.
I followed instructions in this video



And here is my project:


So I have an explode scheme of a holographic sight model.  I saved 3 files: explode_low, explode_high and cage. When I tried to bake without cage - it is work. Not fine but at least I have a result. When I tried to use a Cage - I get a result just like JabbaTheNut. So as I learn from this discussion - UDIM bake is not working in substance. I tried to make separate Cage files for separate UDIM sectors (1011) - still no use. Am I do something wrong or I just should just forget about UDIM in Substance?

[yarogor]

So I get rid of UDIM textures and guess what - problem with cage file stays.
Now, if I use a cage file - it uses UV for just one mesh and don't use UV of other's.
Currently I have exploded model of separate meshes with individual materials and UVs.
So here is my files:
LOW
HIGH
CAGE

Another strange thing - when this error appear Cage file uses just one particular HP mesh and apply it to all the meshes. But if I save my files in OBJ format - cage choose another particular HP  mesh))) So In both situation I get 1 of my meshes baked correctly ))))

So I need any advise how to fix that error. Because for now only solution is to make Cage files to ALL meshes individualy and (of course) bake them individualy.