Texturing can be a simple process for some artists and a baffling void of common sense to others. While the idea of flattening textures isn't new the concept of cramming them all down into one UV tile, no matter the size of the map, lead to some textures being subpar as the entire texture set was located in that one UV tile.
The simplified version with UDIM is we get to put as little as one object per tile which greatly improves the resolution as you are no longer shoving the entire texture set into just one tile. Just the shirt, for example, can go into one tile instead of sharing space with everything else. You can even put parts of the shirt in their own tiles depending on the situation.
Before we go any further let's get the basic UDIM lowdown from FXGuide:
UDIM stands for U-Dimension.
UDIM is a way of creating a single linear number that identifies each integer block in UV space. You do this by defining a limit on the number of patches you can use in the U direction (the U-DIM) and then resetting U to 0 and incrementing V by one after reaching that number. i.e. fill in all the patches up to U=10, then go back to U=0 and go up a line in V. In fact, while UDIM could use an U base number, 10 is now the default and almost exclusively the only number used.
The UDIM number starts at 1001 with the U=0,Y=0 being 1001.
It makes texture layout a breeze as you no longer have to twist, turn, and resize each object into an available free space. You still need to be efficient but being able to put them into several tiles is a real-time saver which means money saver on a production budget.
If software like Marvelous Designer is a part of your production pipeline then all the better as it's UV Editor has the multi-tile map already built-in. You just lay it out and save.
To get here Substance Painter became UDIM friendly and Reallusion integrated it into Character Creator 3 for those that use the method. Reallusion even provides a preset to use when exporting the textures from Substance Painter.
When it came to working with CC3 characters I had no problem with the Reallusion or Marketplace items that were CC3 Plus. Others seemed to need conversion to CC3 Plus to enable the Substance Painter button in CC3.
The curious part was… and I still haven't got a grasp on this… not all CC3 Plus custom characters worked. On update, only the pants would update and everything else got an error about making sure you have the same characters loaded… which to my knowledge… I did.
To get to this problem I exported a blank CC3 character as an obj and into Marvelous Designer as an avatar. I then made a few items of clothing like pants, shirt, and vest. I exported the clothing from MD into CC3 as skinned cloth or accessories. From there I exported the character and clothing from CC3 using the Substance Painter export option.
So far, so good.
In CC3 I selected the items I wanted updated which brought about the pants update… though improperly mapped… and error messages out the kazoo. It was also very hard to read the messages on a 4K monitor as the text is rather small. The gist being I didn't have the same character.
To figure this out I downloaded my latest character from the marketplace, and it zipped through the pipeline as you'd expect. Next, I tried a different custom character and got the error messages with the ill mapped pants again.
I think I'm figuring this out. Custom characters don't work?
So… I then loaded the custom character version of the same marketplace character that zipped through the pipeline… expecting it to not work.
But damn it… it worked!
Now I'm really lost and, for a while at least, decided to put it aside for now as I can still drag and drop the textures from the generated folders, but that kind torpedoes a large part of the integration. In my cases it's still a step forward as the software I use is UDIM friendly and I have to manually drag and drop textures anyway.
Obviously, I'm not using the integration properly. Maybe if I actually took time to really view Kai's tutorial instead of it being background noise I'd probably figure this out by deadline. Then there is always that thing… what's it called… oh yes… the manual!
RTFM! No telling what I might learn.
Instead… I have a topic for another article for another time! So, bear with me while I try to figure out what rabbit hole I've gone down, get my bearing, and get back on track to use the new integration to its fullest.
M.D. McCallum, aka WarLord, is an international award-winning commercial graphics artist, 3D animator, published author, project director, and webmaster with a freelance career that spans over 20 years. Now retired, M.D. is currently working part-time on writing and select character development projects. You can learn more about MD on his website.