Skanect: Colors look washed out when exporting to Sketchfab


#1

I’ve been experimenting with the Skanect software and used the built-in Sketchfab upload function. I’ve found that the colors always turn out rather bleak and washed out, like in this test I did:

In contrast, scans from ItSeez3D (that also uses the Structure scanner) look much more vibrant:

I see this all the time on Sketchfab, any idea why?

Full disclosure: I work for Sketchfab


#2

I find the same thing.I’ve tried various formats, but I believe it is because Skanect uses low res 640 x 480 photos to produce the texture. Even if the model is saved with vertex colors, the low resolution is a problem with the final rendering. ItSeez3D on the other hand uses hi res photos to produce the texture files. ItSeez3D texture files are 4096x4096. I see Skanect texture files at 1024x1024.

I used blender to transfer the texture from an ItSeez3d model to a skanect mesh. I inadvertently left the newly created texture image at 1024x1024 resolution and could not figure out why the new texture looked so poor. A little investigation revealed that it was the low resolution. I did a new texture image with 2048x2048 resolution and the results were astonishingly better. Next time I will try 4096 but the file size gets to be a problem.
Hope this helps.


#3

Hey Bob!

Actually, the scans that Skanect uploads to Sketchfab don’t contain any texture maps at all - they’re only using vertex colors. That in itself already severely limits the resolution of course. But on top of that, the vertex colors are encoded in sRGB instead of linear RGB. As a result, they’re gamma corrected twice, which leads to the bad colors.

It would be great if they could be converted to linear RGB before uploading :slight_smile:


#4

Hi Bart,
Interesting but I’m a little confused. I’ve put up models on sketchfab and I use a zip file to include the textures after saving or exporting the models from skanect along with the texture. The tools on sketchfab allow you to ensure the model has the texture applied. If the textures are low res as in Skanect output, then they really aren’t very good. If you’ve ever tried uploading ItSeez3D models on sketchfab, you can see the difference in the quality of the texture. I don’t know enough about sRGB vs RGB but can photoshop or blender help before sending?
Still, I’d like to see better contrast controls on sketchfab, but lacking that, it makes me try harder to improve textures before sending them.


#5

Maybe it’s because I’m using the build-in ‘upload to Sketchfab’ feature? I haven’t tried exporting to OBJ yet. And sure, you could use external tools to fix the texturemap, I’d just like to see the upload feature work correctly :slight_smile: