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UDIM in 3d coat

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At current 3d coat not full suport, but you can import UDIM tile as separate UVset and material. 

when you import paint mesh (low poli) to Paint work space. you can find option. import tiles as UV sets , you need to check it ON.

Basically it can generate all texture for each UV sets, when you paint. 


Btw I have some request which related UDIM work flow.  

1. If I use the option, 3d coat auto exchange my material group setting, as each UV sets.  (UDIM tile number)  then, if I have 10 material group with 5 UV tile,  mesh change as 5 material group , with 5 UVsets.  it make me difficult to use selection with material group. (I need to remake selection set with mask etc)

2  when import paint room object to retopo room, 3d coat not offer options.  so all one mesh group gathered as one.

  then I need to work in retopo room, to divide mesh for sculpt baking correctly.  I feel it is kind of bug.

it not only pick current visible mesh (tile) of paint room. (I disable some part of UV sets) , but just import all to retopo room.

(though the funciton discribed so, it not work, it just import all mesh include not visible in paint room)

It seems better divide my request ^^;  

Edited by tokikake

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Thanks to all for the replies. i was attempting to create UDIM in 3d coat. But surface objects in 3d coat were treated as separate materials in Unreal (game engine).


As this was the first time i am trying this, i have not idea what wrong went with the process or was it the recipient program didnt work using UDIM.


However,  i have managed a hackish way of doing UDIM in 3d coat and using that in a single material in Unreal.

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8 hours ago, pickers said:

Thanks to all for the replies. i was attempting to create UDIM in 3d coat. But surface objects in 3d coat were treated as separate materials in Unreal (game engine).


As this was the first time i am trying this, i have not idea what wrong went with the process or was it the recipient program didnt work using UDIM.


However,  i have managed a hackish way of doing UDIM in 3d coat and using that in a single material in Unreal.

I see as game assets, maybe most of game engine like one material group for perfromance. (though Unreal and unity both already offer, shader grroup assgin) At same time, I can not find good workflow Use UDIM with One material group, or Use UDIM tile, with free material groups. 

The main problems seems change in each room.  (and I hope 3d coat dev check paint and retopo room with each work flow. they may understand why current way is not good or force user un-necessary work .

About paint room,, UDIM tile and material group can not divide. at least 3d coat treat them as same. so we can not set  materrial group free. (gather  or separate  uv tile) 
Though the main usage of surface group is, which shader  will be applied. but  anyway  3d coat may need to  treat material group as "selection polgion group" of each mesh

So it  should not link with UDIM tile at all.   


about Retopo room,, it seems more complex.. we can set UV tile as I like, but at same time, there is no surface (material group) but offer Retopo group.

Sometimes Retopo group seems used as material group meaning, (3d coat may use the retopo group, when send mesh to the paint room) 

but when import mesh, 3d coat simply remove all material group.  About this case, Retopo gorup = it is just  separated object parts.  So I suppose,, Retopo room need to keep material group infomation. at least when mesh was improted or transfered from Paint (UV) room. 

I know, 3d coat separate mesh for each room,, but about retopo mesh we actually have no material group and no way to assgin it.  Retopo group should not be used as material group.

(though 3d coat seems use it as materail group with some export option, but after all it will link with UV sets)

"UVset (aka UV tile for UDIM) ", "Material Group",  and "Retopo group"  these 3 groups may need to be separated clear.  

I aleady serch around google, with those words and 3d coat,, but most of them discribe same problem for each purpose.  And I know there is already almost same topic related with this,

(many advance user, digman, carlosan, etc already show their infomation,, ) But unfortunately,, this prolbem have not been solved and remain. :unknw:

So I hope,, user may show their view and request Devteam, as one gather view. (Maybe other user have more good idea, how to think these gorup, and how it is represented in 3d caot, and how mange them in 3d coat)



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I edited my statements to await the development response to a bug report Carlosan submitted.

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Haikalle thanks offer test version.   I test and report later with some cases.:)


Do quick test in Paint room and UV room.

I can not believe it actually happend ^^;


Now I can see all mat group for my import FBX from blender,  but it keep UV set with tile number.

(I use option, import tile as UV set)

One thing I found,  When I check UV in UV room,, it seems not be shown as tilled UV,, 

 but if I export mesh with UV,, it return tile, it seems no problem for me. At least I could confrim, 

3d coat could export texture for each UV sets, (not for each material) . 

when I see new version paint room, I can not believe why it had not imporved untill today ^^;  Anyway thanks all your effort! and 3d coat team!

I may check how export UV set will be shown, and see if it will work in retopo room (though I already suprised enough)


I see current prolbem seems , it can not keep UV as UV tile when I export ,(I test with  export uv set as tile, Active, and  non Active)

as FBX..  (if I use export UV set as tiles, it seems merge all verts,, if I do not use export uv set as tiles, it only show first material UV tile. 

(not set as UV tiles any more, they locate 1001 space)  I do not know if it is blender FBX improter problem or not. (test with 2.91)

to edit texture in texture room ,and export texture for each UV set,, there seems no problem already.

More test.

When I export as obj, it keep UV set, as UDIM tile,  and keep all material group without problem.. So 3d coat seems work as same as before about export option..

(maybe bender FBX importer problem? I do not know  how blender improt FBX with UDIM tile, without use app-link,, so I may test with app link again)


And I really apreciate,, as future request,,,   retopo room will show surface group too ^^;  (Though It need new panell or UI I think)

Edited by tokikake

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At first thanks much haikalle you really improve work-flow for me. :rofl:

 about Paint room, now import mesh with UDIM uv plus material group (shader domain, or surface mat group etc) then export mesh with keep imported UV work almost perfect.

Then  I hope 3d coat dev team may improve, UV room and Retopo room <> paint room work flow. 

I am not advanced user, so maybe other user offer more good view. even though I import UV tiled mesh, in paint room, (and it keep each UV tile as UV sets)

Current problem which I think it may need to be improved are,


1.   UV room not show UV set as UV tiles.   to edit UV as UDIM way,  in UV room and Retopo room,  we may need grid UV  as UDIM  with number.

And each UV set may need to locate in the UDIM tile as visual infomation.

At current if I check current UV in UV room,, all UV sets are located on same UDIM space, without show grid number. 

  (I suppose all UVset are now located on same UV space (1001) , when  I check mesh in UV room )

It make user difficult to set UDIM tile in 3d coat. (in paint room , it is not problem,.  when we export mesh,  it generate UV tile with UV set number.


2  Almost same thing happen about Retopo room.  I can locate each UV as I like,, but it not show any grid number as visual infomation.  and usually when we set UDIM, 

we may hope to move mesh, as UDIM unit, but 3d coat not offer way. (so I move and scale with transform widgt on UV space, 

, but sometimes we need to translate U direciton as 2 unit, V direction as 1 unit etc) 



3 As I said already, when we export mesh from Retopo room to Paint room (by bake option),  it seems auto set material group as UV set name.   

But what we really need is, offer way to assgin material group (not retopo group name). I think at current there is no room where we can assgin material group. 

Hope 3d coat keep the material group and UV tile,  which user defined for all room. when we transfer same object between Retopo <> paint (UV room)


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4 hours ago, haikalle said:

Thanks for feedback. two main things:

1) Do you think I should add this "Materials are kept with udim" feature into official 3D-Coat release?

2) about UV / RETOPO ROOM. Many has asked this feature that users could see all tiles in uvmap at once. I think it would be nice but I also think that there is maybe other ways to implement this. Vision what I have is that you could select two (udim)tiles side by side and then move uv islands between them.  If you have like 20 tiles in udim, navigation/moving island could become quite confused prosess if you see them in one uv map.

3) Other idea I have is that you could rename udims(1001,1002...) into names as you wish. For example rename 1001 into "Armor/Metal". Under the hood 3D-coat would still use numbered tiles but names would be only users eyes only.

fixed again some udim bugs from applink.

my answers are

1) For me current status is ideal for texture in 3d coat workflow.  And if there is good clear documents about UDIM import paint room work-flow,

Most of user may easy understand, how it work. (when import and export, setting options)

Then,  about FBX export (from 3d coat), some aprication may not re-generate UV-tile as same as before.  eg recent blender, if you export mesh with UV as FBX from paint room,

actually it gather all UV tiles, in 1001 space.  (I can not still confirm, which side problem.. but if I export FBX from blender as UDIM ,then return same FBX to blender, it can keep UDIM tiles.

So I suppose,, FBX code format cause this issue.  (It often happen, even though we improt same file, each aprication may show differently.. some infomation will be lost etc)


2) I have used  UDIM tiles,,  basically even though there were  100 UV tiles, it not cause problem to set UV tiles..when user can see UV tile number (or there is grid) , and user can zoom in out full UV tiles in Editor and Can transform full UV grid.. (actually we did so, in most of aprication, when we set UV on to another tile (non 1001 space)

 we start UV unfold,  on 1001 place.. then we may move them to different tile, (and edit scale etc). .

even though there is no visuall number, if we can detect the 1001 tile area as clear separate color,  with grid, we can move island in the UV view tool.  and can see, which UV located on which UV tile as visuall.  (we only need zoom out,, and see  whole tile in the UV view).

Side by side view seems good idea, but at same time, it may only work well, user already decide, which part will move to which tile.. (On the other hand show all UV tile at once,, then we move full UVtile in view, offer more flexibility edit, I think)

UV only need 10 X 10 grid as max.. it is not difficult to see whole area in UV view.  (with scroll zoom in and out)  as same as we see Othero game.in small View.

At same time we may need tool, to move selected UV parts with Units..(step transform option) for transform widgt and input U V value, (as same as transform tool which offered already in other room (we can input value)

Eg  blender offer short cut,, G + X (U) + X(U) unit number,      and G, Y (V),  Y(V) unit number..on UV editor. so I can really quick move selected part to tile which I hoped to.

3) It should be welcom improvements,, Actually current 3d coat can name  UV sets as I like, at same time it cause some miss-understand when user set UDIM, I feel. 

(Then I did not know, if there is meaning to set number for each UV sets,.. I can not detect, which infomation 3d coat use to set tile.. (case A,, 3d coat simply use UDIM tile, where we locate UV island, or it is decided by UV set name,, or 3d coat may only use UV set number, with export option,, (generate tile as same as UV set name, so if we set it as mytile1 etc, it may not work when generate UV tile in another aprication,,)

Anyway, if there is clear tip small document,, User can learn how to., if there is not,, we may see many question in forum I believe  ."What UV set name actually means? " etc.;)


I suppose the youtube training video tutor, often use many apricaitons, and have offered some UDIM tutoriall, so it seems best to ask him, and how he think..

He know almost everything, for UDIM work -flow I feel, (and each aprication limit), As my opinion, we may need new options in UV room. so after bake retopo mesh, we an re-locate and edit UV as UDIM manner..  (UDIM is for texture map, so  paint room (UV room) is best place I feel.. )

Of course if 3d coat try to offer all options of UV room in Retopo room UV tools, I apreciate it..  At least I can say,, when I work in current 3d coat retopo room, I almost need to forget about material group.. then concentrate UV set,, but UV tool not offer good manipulation tool to move UV with grid ^^;)

Without desgin carefully, new enhancement may offer confusion, 3d coat may show difference things, when we import mesh (UDIM with mat group) in paint room and Retopo room. then after bake and transfer retopo mesh to paint room, then export,, we see UDIM have been lost in some step,, (but user can not detect which porcess cause this issue)

Edited by tokikake

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Sorry I forget one important thing ,,, actually it need for paint texture with Texture editor.

I said,, it may ok even though all UDIM gather in paint room as visualll (we only see one UVset (UV tile) at same time)

But it is not so good ^^;  because case by case,  we paint texture directly on to Texture 2D editor too. Eg I may pick color for 1001 area to 1002 part

or use Clone tool etc,,  with Texture editor. 

Current 3d coat only show current selected UV set (tile)  in 3d View... (Though I suppose it for peformance ,)

So even though I not request it,, maybe after UDIM support many user will ask same thing .. 

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I test for FBX and OBJ export from paint room, with use same options and same mesh (it imported as UDIM mesh with haikalle offred test version 3d coat.exe)

Now I can clear see, about FBX it break UV (it not matter which option I choosed, (export UV tile as UV sets or not)


And just to confirm, if I direct re-import as FBX from Blender (without import in 3d coat) it not happen. (keep UDIM tile).

So 3d coat export fbx seems lost infomation, or blender fbx importer can not read it correctly.

Export from 3d coat only change file as OBJ. then import to Blender.


I do not know if 3ds max or maya etc, may show same issue. I test with blender 2.83 and 2.90, 2.91 (each branch recent version)

If 3d coat Applink use original FBX importer, it may not happen I suppsoe. (though I first test without applink.. (it may need for other app user)

Edited by tokikake

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On 9/16/2020 at 4:33 PM, haikalle said:


fixed again some udim bugs from applink.

Haikalle,  Does this version is most recent version?   The attached version show version number as 4.9.34

Then what I got from applink thread (thanks you up-date to improve often) show as 5.0.0

So I am now thinking, which version I should use ^^;  

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Just now, haikalle said:

@tokikake Yes that the latest. I will start to rename this files differently so user can see better which version it is.

Thanks,, now I see measurement old trouble in 3d coat ^^; and struggel with it,,, hope to know how haikalle set those setting,,,

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