Help : bad/screwed UV from blender


(Garrom Orc Shaman) #1

Hi all. I created 3d model Blender but UV seems to be crewed.
Here is how model look in sketcfab


I'm sure you already know this is not how it is supposed to look like
What i can do to fix it ?
Thanks
-Garrom


#2

Hello,

I'm sorry you're having trouble. Can you please share a link to the model so we can have a closer look? I just increased your forum permissions so you can post links.


(Garrom Orc Shaman) #3

Yes. Here it is: https://sketchfab.com/models/7b76abf65c614cd587a96420fce53455
And thanks for permissions .


(Garrom Orc Shaman) #4

Hmm. This is interesting. If i'll limit my cpu to 1Ghz, first two second after view loads it looks fine and become bad after time what means it is some process what happens separately. With dual core 2.6 Ghz i have no chance to notice. Thanks god I'm developer, i got tools to limit own hardware for debug


#5

Hmm, I'm not sure I understand the issue. Can you post a screenshot of the model in Blender?

Thanks!


(Garrom Orc Shaman) #7

Sure, i can.


Nothing fancy just very simple voxel model with single animation. Obviously, it is problem with UVs. Do sketchfab doing compression of model data ? UVs to be more specific. Model is created in VoxelShop, blender is used only for animation and fbx export.
Here it is how it looks in Voxel Shop:

As you can see, everithing is fine as long as i don't upload anything.


#8

Thanks. @stephomi any idea?


(Garrom Orc Shaman) #9

Nevermind. Looks like problem was not in Blender but in voxelShop. Imported model has overlapping UVs and texture was not power of 2. Looks like sketchfab cannot work with overlapping uvs and textures what are not power of 2. It will be nice if someone write article about what sketchfab can work with and what sketchfab cannot work with. Nowhere is written "You can't have overlapping uvs and texture must be power of two".


(Stephomi) #10

Sketchfab is working fine with multi-uv and non power of 2 textures.

Non power of 2 textures are resized automatically and you can select the UV channel in the material editor.

I can't tell if your model has multi UV or not as it's now deleted.


(Garrom Orc Shaman) #11

No, only one UV. By "overlapping uvs" i mean multiple faces use same part of texture. Looks like it was problem because it is not standart use of UVs / Textures. Model was re-uploaded with non-overlapping uvs and it works fine now.
Here is link : https://sketchfab.com/models/4c6f4a783e754ff7a5737ecb11c2a177


(Stephomi) #12

Sketchfab is also working fine for faces that shares the same part of a textures (or even sharing UVs).
It's not really special, most 3d engine will support that actually.

The bug was probably lying somewhere else, maybe exporting or the processing on our side (can't tell because the model is deleted).

But it's fine if you found a workaround!


(Garrom Orc Shaman) #13

It took a while but I finally found REAL cause of problem, to be honest, I found it by accident. If textures are not power of 2, sketchfab will apply “video RAM compression”.
From GoDot engine Docs :
VRAM Compression: This is the most common compression mode for 3D assets. File on disk is reduced and video memory usage is also reduced considerably. For 3D, it may present unwanted artifacts, though.

I’m sure that what are we seeing are mentioned “unwanted artifacts”. Apparently, for power of 2 textures is used something less destructive, something without those unwanted artifacts. I know that some better compression methods can work only with power of 2 sized textures.


#14

We actually never render non-power of two textures in the viewer. We generate multiple resolutions of textures from the original and choose the best one.

https://help.sketchfab.com/hc/en-us/articles/202600873-Materials-and-Textures#textures