I have problem with sketchfabs color management. I have finished my model and animation, but i can't publish it till bug is fixed. Normal maps are being interpreted wrong.
Check it out here. https://skfb.ly/TANZ
As you can see some of the moving parts get normal map inverted at some point in the movement.
I know its a color management problem, because on exactly the same polygons, at exactly the same time had same problem in Maya 2016 viewport 2.0(other renderers work fine). I spend crazy amount of time in looking for the cause, I deleted all mesh normals and recalculated them countless times and even remodeled some of the meshes, but for my surprise nothing worked. Then finally I started to google around and found that that's just a color management bug in viewport 2.0 and there is easy fix by changing color space to Linear.
Here are couple of links about the problem-
Problem in Sketchfab is that color space already is Linear. Switching to sRGB gives even worse result, so that's how I am 100% sure that's color management problem.
I have written this to support, but there hasn't been any response. Please don't ignore this. It should be easy thing to fix. Thanks!
P.S. I did similar animation 2months ego and there wasn't this problem. I also noticed this problem month ago when I did other simpler animation, but it was not big deal on that one so I didn't look in to it that much.