Jump to content
3D Coat Forums
Carlosan

UDIM UV mapping

Recommended Posts

Texturing is central to 3D.

From UV to UDIM to Ptex, it is easy to think one technology has just displaced another, but the reality is more complex.

UDIM UV mapping has enormous popularity for texturing in the face of much newer systems such as Ptex (which works very well in its own right).

While Ptex may still yet win the texturing heart of pipelines around the world, it has not yet become the dominant force.

 

The article at FXguide

 

udim.jpg?62f061

 

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.

 

//note:

Proper UDIM support in 3DC was implemented after v4.5 BETA4

Share this post


Link to post
Share on other sites

So, is Andrew going to offer an option to work with UV Tiles, or no? I read something about UDIM support, but supporting them imported in or exported out isn't the same as actually working with UDIM/UV Tiles inside the app

Share this post


Link to post
Share on other sites

UDIM is just another way to use UV tiles. It's an automated way for programs to work together with very little fuss. You import, it looks at the tiles and converts them to UDIM numbers, you export, it places them right back where they were, exports the images with their UDIM IDs, and you import in your host app. Done. Try it out. It works quite well.

 

 

As far as importing UV tiles (outside of UDIM), you'd have to ask Andrew. I've pressed him for years, this is the closest I've got.

Share this post


Link to post
Share on other sites

So, is Andrew going to offer an option to work with UV Tiles, or no? I read something about UDIM support, but supporting them imported in or exported out isn't the same as actually working with UDIM/UV Tiles inside the app

Was wondering that myself, AbnRanger

Plus all those nice additions to the retopo room that you posted at Mantis which would make our life easier even if we do get UDIM support...

Share this post


Link to post
Share on other sites

We do have UDIM support. :)

LOL, Ok Javis in a round about way... :p:  but it is there...

Share this post


Link to post
Share on other sites

Was wondering that myself, AbnRanger

Plus all those nice additions to the retopo room that you posted at Mantis which would make our life easier even if we do get UDIM support...

 

 

UDIM support is quite important for texturing and the I/O process. It cuts down on a lot of time and makes it a lot easier. I'm not sure what it would have to do with retopology though. I would like the ability to create, view, edit and export actual UV tiles outside of how Andrew is doing it now, with the same support for UDIM. That would be the best of all worlds. But Andrew wont be doing that any time soon. He tells me it requires a serious overhaul of the entire engine of 3DC. But I say press him.

LOL, Ok Javis in a round about way... :p:  but it is there...

 

Sorry about that, I hit the wrong button. I meant to edit, not delete my post. Doh.

Share this post


Link to post
Share on other sites

It's been my understanding that one of the major benefits for UDIM/UV tiles is that it allows you to work across multiple UV tiles at once, and don't have to worry about seams between them. Right now, in 3D Coat, you can only work on one (UV set) at a time. I don't know if Mudbox uses UDIM, but yeah...if it at least assigns the tiles back to where they were, that's a step in the right direction.

Share this post


Link to post
Share on other sites

That's not a benefit of UDIM at all, that's a normal function of all 3D programs, except for 3DC. It's a problem of 3DC and should be made to work like other programs in that regard. But as I said above, Andrew said it would require an entire rewrite. I hope it happens, but it's only been myself and a few other clients pressing for that. Andrew doesn't seem eager to do that.

Share this post


Link to post
Share on other sites

Np Javis... B)

 

Yeah, the last part of my statement as nothing to do with UDIM but was only a hint, hint that those features AbnRanger and a few you have asked for in the retopo room would be great to have for tradtional uvs or UDIM. Would let us work smarter not harder... :)

Edited by digman

Share this post


Link to post
Share on other sites

...Right now, in 3D Coat, you can only work on one (UV set) at a time...

 

This is not true.

You could always paint on mutlible UV sets at a time.

It makes no difference if one object use two UV sets or separatet Objects use his own UV sets.

Share this post


Link to post
Share on other sites

I'm talking about using the Texture Editor and/or laying out your UV's. I knew someone was going to come along and question what I said about that. I should have stipulated that, but didn't think I needed to.

Share this post


Link to post
Share on other sites

To elaborate further, texture artists who like working with UV tiles in Mari and Mudbox, mention that (for example) you can have a Head UV tile, a torso UV tile, arms and so on...and have them stitched together across multiple tiles and then use large res image overlays for stamps or stencils across all those tiles (when painting in 2D mode).

Share this post


Link to post
Share on other sites

That is different than UDIM, that's simply having proper multiple tiles viewed properly as one UV map. They are not mutually exclusive. Either way, there are mantis reports, let's flood Andrew with 'em and get him to rewrite the core engine. :)

Share this post


Link to post
Share on other sites

From my experience, I remember that working with UDIM in 3D-Coat was possible, but time consuming, awkward and prone to user error.

First of all, you had to move your UV's manually outside of (0, 1) UV space in a 3rd party program, simply because you couldn't do it inside 3D-Coat.

Then, you had to import that stuff into 3D-Coat. Importing to Retopo Room kept the tiles intact.

After setting up bake scan ranges and all, you had to choose this option called Import Tiles as UV Sets.

And it did what it said it does.

Finally, after painting textures, you needed to export them with Export UV Sets as Tiles, but it threw everything into one bucket. So if you had several objects using UV's inside (0, 1) UV space (let's call them objects A and B), and an object D that used, for example, five 2k UV-tiles, 3D-Coat treated all of those guys as tiles and exported as so. So, UVs of objects A and B, even though they were initially inside (0, 1) space, could land with great probability outside of their initial UV space.

This said, you had to correct the placement of all of the UV junk in a 3rd party program and also rename the files according to UDIM specification. This took a long, long time. This was probably the most time consuming part of the whole process.

I'm writing all of this in a past simple tense, because I don't know how things look like after Beta3 update.

From what I read, Andrew implemented UDIM-compliant import routines, but I didn't have a chance to try them out yet. I I assume they treat every imported UV tile as UDIM and place them in a appropriately named UV tile. So it's a step forward towards UDIM support, but still - a small one.

Feel free to correct me if I made a mistake somewhere.

Edited by ajz3d

Share this post


Link to post
Share on other sites

Oh yeah, like Don said, it's still not possible to seamlessly paint over tiles in UV Texture Editor.

Edited by ajz3d

Share this post


Link to post
Share on other sites

From what I read, Andrew implemented UDIM-compliant import routines, but I didn't have a chance to try them out yet. I I assume they treat every imported UV tile as UDIM and place them in a appropriately named UV tile. So it's a step forward towards UDIM support, but still - a small one.

Feel free to correct me if I made a mistake somewhere.

 

That's pretty much what it does. It works well, for what it is.

 

Oh yeah, like Don said, it's still not possible to seamlessly paint over tiles in UV Texture Editor.

 

One day, hopefully with enough pressure from the user base, he can't refuse right? :)

Share this post


Link to post
Share on other sites

It just occurred to me that one reason why Andrew may have been holding off on this for so long is "performance." 3D Coat does pretty well up to 4k maps, when painting on one UV map/set at a time...but go up to 8k, and it starts to slow down considerably. So imagine trying to paint across multiple 4k+ tiles. It might start to show some real weakness, in terms of performance. We STILL need for him to optimize the sliders in the Paint room, because they are practically useless unless you are working on a 2k map or smaller.

 

I wonder if he switched to DX11, would that help. We've been on DX9 since the Dinosaurs walked the earth. :)

Share this post


Link to post
Share on other sites

Just learned the hard way that the new UDIM implementation in 3DC ignores UV-set names and exports them in order as seen on the list of UV-sets. And the problem was that on that list I had 1005, 1001, 1002, etc. If only we could reorder UV-sets...

Edited by ajz3d

Share this post


Link to post
Share on other sites

Hi ajz3d

The problem you mentioned was solved in version 4.8 ?

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×