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[SOLVED] UV Mapping For Unreal Engine 4


ScrotieFlapWack
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So I have run into some issues with the way UV's work in 3D - Coat and how Unreal Engine 4 reads them. I've been trying to mirror certain UV islands to save on texture space but UE4 interprets those UV islands as overlapping. Is there another way to mirror UV's rather than the copy and paste method?

 

I've already posted this issue over at the forums and people have just come back and said that due to the UV islands being on top of each other that is technically overlapping. I must be missing something haha any help would be appreciated :D

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So I think I have managed to find the answer to this question. UE4 needs lightmaps for static meshes. When a static mesh with one UV set is imported into the engine it uses that UV channel for textures and lightmaps, lightmap UV's can't be overlapping so the only way around this is to make a second UV set for the lightmaps. 

 

Thought I would supply the answer here for anyone else who might be using 3D - Coat and UE4 :)

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Unreal Engine only supports a single UV map for actual textures (but multiple materials)

 

You need non-overlapping UV's for your meshes in order to bake the lights properly.

Source

https://forums.unrealengine.com/showthread.php?748-Error-Lightmap-UV-are-overlapping-by-40

 

ty for sharing

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This might be a stupid question (actually I am pretty sure it is) but in Unreal Engine 4 they have 'UV Channels', am I right in saying that UE4 'UV Channels' are the same as 3D - Coat's 'UV Sets'? 

 

They are both the same thing?

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Is there a way to copy UV islands into another UV set? 

 

I want to copy all of this

 

http://gyazo.com/7b00b6e7877d933cc14dfa65be223596

 

Into another UV set, without moving them somewhere. I know how to move them into another UV set. I want to know how to copy them into another UV set :D

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For some reason I don't have 'Clone' in my menu :(

 

I should mention I am using the Steam version of 3D - Coat.

 

Is that option in the retopo room? Cos I don't see it anywhere haha

Edited by ScrotieFlapWack
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I think I am missing A LOT of stuff. The Steam version isn't updated as regular as the standalone version as far as I'm aware. 

 

Please Andrew update the Steam version, I'm developing a game here and I NEED these new features :D

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This is in the UV room? 

 

Ok I got it now. It's in the retopo room. Only problem is it doesn't seem to work for me. I will select all the faces then press 'Clone' then I go to the UV set I want to clone it to and press apply and nothing happens :(

 

EDIT: 

 

Ok so I have tried this a few times now and it seems that something is happening but not what I expect. I can see the edges of my model in the other UV set and when I press the button to select all faces in that UV set they appear to be there but only the edges I can't see any faces at all or the checker texture for UV'ing with. When I go back to my other UV set on the model everything appears to be there as before.

Edited by ScrotieFlapWack
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So here is my first UV set. For my textures.

 

http://gyazo.com/d868278e0f9eab76b2bdce82464573c7

 

I want to copy this UV set into the Lightmap UV set I have added.

 

http://gyazo.com/c46743a58aa3d78c3b152c5d0ba6a809.

 

The clone tool in the retopo room doesnt work. All it does is copy the faces of the model. It doesn't unwrap anything for any islands to show in that UV set :(

 

It looks like this guy is having the same problem as me ..... 

 

http://3d-coat.com/forum/index.php?showtopic=11715

 

You posted in that thread Carlosan ...

 

i have done a model in Blender with 2 UVmaps

the UVmap1 was assigned like default for render

exported the OBJ, and imported it in Retopo room like uvset1 (Retopo > import)


then same process...


the UVmap2 was assigned like default for render

exported the OBJ, and imported it in Retopo room like uvset2 BUT first i create a new uv-set

Now i have the same mesh with 2 uvsets

When i bake for PPP, in the paint room there is one object with 2 uvsets and 2 materials

is this what you need ?
hope it help  :) 

 

This is EXACTLY what I need to do. I was wondering if you could explain though how you did this? Would I need to import my model twice but in different UV sets?

Edited by ScrotieFlapWack
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yup

http://www.worldofleveldesign.com/categories/udk/udk-lightmaps-01-basics-and-important-principles-for-creating-using-lightmaps.php

----------------------------------------------

1 UV channel means the object has texturing UVs:

009-lightmap-principles-08.jpg

 

2 UV channels means the object has both texturing and lightmap UVs:

009-lightmap-principles-09.jpg

2. Second UV Channel

For your static model to light/shadow properly you need to create a second UV channel inside modeling app such as Maya or 3dsMax.

You could generate unique UVs in UDK within Static Mesh Editor, but the best way is to create a custom set of UVs is using a 3d application. This way you have complete control over how lightmaps appear in your map.

In the second UV channel, the UVs will be laid out specifically for lightmaps. The way you lay them out will be different then you would for texturing.

To create a second UV channel in Maya do the following:

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yup

http://www.worldofleveldesign.com/categories/udk/udk-lightmaps-01-basics-and-important-principles-for-creating-using-lightmaps.php

----------------------------------------------

1 UV channel means the object has texturing UVs:

009-lightmap-principles-08.jpg

 

2 UV channels means the object has both texturing and lightmap UVs:

009-lightmap-principles-09.jpg

2. Second UV Channel

For your static model to light/shadow properly you need to create a second UV channel inside modeling app such as Maya or 3dsMax.

You could generate unique UVs in UDK within Static Mesh Editor, but the best way is to create a custom set of UVs is using a 3d application. This way you have complete control over how lightmaps appear in your map.

In the second UV channel, the UVs will be laid out specifically for lightmaps. The way you lay them out will be different then you would for texturing.

To create a second UV channel in Maya do the following:

 

I know what lightmaps are and how UE4 handles them. I need to know how to do them in 3D - Coat. Is it possible? Can you have one mesh with TWO UV SETS in 3D - Coat. I don't mean one mesh with multiple UV sets to texture different parts of the model. I mean one mesh with TWO UV SETS that are the exactly the same for ONE model?

 

Please somebody tell me how to do this. It seems I can't get a straight answer from anyone. Is this possible in 3D - Coat, if yes then how? If no then that's fine, I can stop wasting my time here asking and get another modelling application which will be able to do this.

 

I'm sorry about the capitals but it feels like nobody is actually understanding what I am talking about. This is a regular thing that artist's need to do and I am really surprised that 3D - Coat can't do this (from what I have found so far.)

Edited by ScrotieFlapWack
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Would I need to import my model twice but in different UV sets?

i guess yes, please try

 

//edit

you asked about UVChannels, i just reply the info for any1 that will dont know about.

is a good post to share about it.

 

at the beginning i post yup

yup means yes, sorry if i wasnt clear enough

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i guess yes, please try

 

Hey Carlosan, I have tried this last night, 3D - Coat wont let me import the same mesh twice into my project. I will select my 'Lightmap' UV set in the UV Room, then I'll go to the 'Texture' menu in the toolbar and choose import UV set that doesn't work. I've also tried clone and then selected my lightmap UV set and that doesn't work either. I've also tried to copy all the faces in the retopo room and paste them into my lightmap UV set, that also didn't work. I've also tried to import my model in the retopo room into the other UV set, that didn't work.

 

I really don't know what to do next :(

 

I NEED to know how to do this otherwise I'll have to get some other program that can do this and use that (which would be a real shame). I'm developing a game and I'm working to deadlines as well. Sorry if I seem a bit rude :(

Edited by ScrotieFlapWack
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you need to import it in retoporoom

 

UVroom is used to modify any mesh uv placed in paint room

 

import twice the obj

you got 2 groups = uvlayout

post-10142-0-00841800-1407835048_thumb.j

 

 

add a new uvset

post-10142-0-84180100-1407835048_thumb.j

 

Select all faces in one group

post-10142-0-97824500-1407835243_thumb.j

 

Then move selected faces to the new uvset

post-10142-0-22066900-1407835312_thumb.j

 

hope this help

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Ok I guess I'm gonna have to leave this here and stop trying. It looks like you can do this one simple thing in 3D - Coat so I'm gonna have to try out Roadkill or something like that. Thanks for everyone's help though!

 

EDIT: 

 

I have tried all the import options in the retopo room but it still won't work. The mesh doesn't show up in the lightmap UV set I've made this is what I get .....

 

http://gyazo.com/e3dc15311c76003927e1a577f2a9540e

 

No UV islands are there, I can't even unwrap the model to get any UV islands either.

 

@Carlosan, that's just moving the faces to another UV set. I need to copy them to another UV set.

Edited by ScrotieFlapWack
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is your group in the UVset needed ?

 

the island in the uv preview show no polys...

 

post-10142-0-25424300-1407835859_thumb.j

 

i import the same cube with 2 materials and 2 uvset

now i have 2 cubes in 2 groups inside one uvset

 

next i create a new uvset,

select the faces from one group in the first uvset,

post-10142-0-11692400-1407836058_thumb.j

 

and then move selected faces to the new uvset

post-10142-0-49782900-1407836171_thumb.j

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is your group in the UVset needed ?

 

Yes, I need to do this for lightmaps in UE4. If I don't have any lightmaps on my static meshes then I get an error of overlapping UV's because UE4 will use the first UV set (my texturing UV set) as the lightmap UV set as well. This is why I need to copy the same UV set to the same model into a different UV set, so I can then alter those UV's to be used as the lightmaps.

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attachicon.gifcube.jpg

 

i import the same cube with 2 materials and 2 uvset

now i have 2 cubes in 2 groups inside one uvset

 

next i create a new uvset,

select the faces from one group in the first uvset,

attachicon.gifselect all faces in first UVset.jpg

 

and then move selected faces to the new uvset

attachicon.gifmoveselectedtosecond uvset.jpg

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HOLY SHIT! CARLOSAN YOU ARE INCREDIBLE!

 

I am SO SORRY, I wasn't fully understanding what you mean. I have two of the same UV set's now. I have two groups though in the retopo room. What you said though has worked I now have two UV set's that are the same. I need to be able to alter the lightmap UV set though. If I am able to do this then it looks like this can be done in 3D - Coat after all. 

 

Everytime I delete the first group, it deletes some faces :( 

Edited by ScrotieFlapWack
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IDK, never tried in 3D Coat. I do mine in Blender 3D!! IT does the uv second channel for lighting(non overlapping) or a hundred for that matter! Besides I'm very sure that the game engine will generate a second channel for you inside the game engine!! In the Static Mesh Editor. It was in Unreal 3. I don't use it in the game engine now. But it is helpful. cheers!

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