HELP! How can I fix my UVs to work in Unreal?

Demetrius_214 · Apr 2016

-If there's a thread similar to this question, provide a link so I can check it out, thanks!-

I've always been stuck on this part of the exporting process in Maya. UVs, UVs can't overlap in UE if you want the lighting to work properly; I have created two uv sets (which I will provideb below) top image is the one for texturing and the bottom image is the UV set for UE

Image: https://us.v-cdn.net/5021068/uploads/editor/95/j3redg4x8ni9.png

It's been imported to UE and built the lighting to see how it went... and that didn't work well. Here's the images for the mesh (UE images below):

Yes, they're not placed the same way like the Maya version. So I have little idea on why this is happening, please help!

McGreed · Apr 2016

Looks like you have autogenerate lightmap activated when you imported the mesh.
Try double click on your mesh in the Unreal Editor, and then look at it's properties to the right, and see if the checkbox for "Generate Automatic Lightmaps" (or something like that) is checked, if so, disable it and then reimport the mesh.
If you manually imported the mesh, you need to uncheck the box in the import box.

Btw, from the look of your UV layout for the second channel, it doesn't look like you are making full use of the UV space. Remember that the lightmap resolution is usually pretty low, so you should always try to make the best use of the space.
If possible, fill out the 1x1 square, in some cases you can scale the islands to fill it out. For lightmaps you can often stretch it to make better use of the space. Just make sure there is plenty of space between the islands.

musashidan · Apr 2016

As @mcgreed says, plus with uving for lightmaps the usual rules can be bent: forget about distortion and 1:1 scale. Try to have as few seams as possible to reduce padding and bleeding and use as much space on the sheet as you can.

Also, you texture channel is 1:1 and can be scaled right up to fill the sheet.

Demetrius_214 · Apr 2016

McGreed said:

Looks like you have autogenerate lightmap activated when you imported the mesh.
Try double click on your mesh in the Unreal Editor, and then look at it's properties to the right, and see if the checkbox for "Generate Automatic Lightmaps" (or something like that) is checked, if so, disable it and then reimport the mesh.
If you manually imported the mesh, you need to uncheck the box in the import box.

Btw, from the look of your UV layout for the second channel, it doesn't look like you are making full use of the UV space. Remember that the lightmap resolution is usually pretty low, so you should always try to make the best use of the space.
If possible, fill out the 1x1 square, in some cases you can scale the islands to fill it out. For lightmaps you can often stretch it to make better use of the space. Just make sure there is plenty of space between the islands.

and @musashidan thank you very much for the help!

Demetrius_214 · Apr 2016

Alright, I have another issue at hand, can I export BOTH UV sets onto UE? Using one UV set as material while using the second UV set for lightmap?

GlowingPotato · Apr 2016

Yes you can! Just don't generate the light map Uv at import. An then set your Uv channel for lightmap.

Demetrius_214 · Apr 2016

@GlowingPotato I believe I have done that part: before importing the mesh, you uncheck generate lightmaps. Correct? I have worded my question incorrectly, so I'll reword it: The model I've pictured above has two UV sets; map1 and uvset 1. Map1 is used for the textures, while uvset 1 is used for lightmapping. I noticed whatever uv set that's selected for the model in Maya, will be exported and used in UE. I want both UV sets to be exported, but I don't know how to do that; I think this may be on Maya's end, but I'm not entirely sure.

GlowingPotato · Apr 2016

when you export an Fbx from maya, all your Uv sets are exported. Do a test, create a cube, create 2 uv sets, then export an fbx, then create a new scene, and import that fbx and see if your Uv sets are there. you can check for them inside unreal too.

Demetrius_214 · Apr 2016

I'll try exporting them as fbx files. I know importing fbx files on UE would crash?

musashidan · Apr 2016

Demetrius_214 said:

I'll try exporting them as fbx files. I know importing fbx files on UE would crash?

.fbx files store a lot more data than .obj and shouldn't crash UE. What version .fbx plugin are you using?

GlowingPotato · Apr 2016

use fbx 2014/2015

Demetrius_214 · Apr 2016

Oh right! I forgot I can use different versions of fbx files! @musashidan fbx 15/16

musashidan · Apr 2016

As glowing potatoes says, try 14/15

HELP! How can I fix my UVs to work in Unreal?

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