Gloss map for PBR

Armitage19

Hey,

I am trying to find a good workflow for making Pbr materials from real world pictures.
So far, I managed to make good albedo, normal, displacement and specular maps.

But the gloss/roughness is a big problem.
There is a gloss meter but that's useless for textures.

How would you make a gloss/roughness map in this case?

Thanks

Greetings from Japan

musashidan

Whatever you do manually is going to be 'hacked' guesswork, at best. Now that's not to say the results will necessarily be bad when rendered, but I would use a program like bitmap2material.

Armitage19

Well, I was thinking about using that. But, I can real world values for everything beside gloss/roughness.
And then using guesswork for that, cant bring myself to do it.
I really want to have the real world values.

musashidan

Well you're never going to have the exact real-world values because all of this stuff is essentially hacked, faked, and a clever use of trickery/artistic skill. You can do the usual manual work of compositing various derived greyscale maps and adjusting values/curves/etc, but really you shouldn't get obsessed with trying to achieve 100% accuracy. Using your eye, your artistic knowhow, scrutinise refs, and look-deving  until you get a believable, realistic looking render should get you there.

Even auto-solutions like B2M is just the computer guessing......but quicker.

leleuxart

The real world values of gloss/roughness are too varied across a single surface. It's not really worth the hassle of matching it perfectly, when you can generally eye-ball it and test it in various lighting conditions and camera angles to get it close enough. 

Armitage19

Yeah, but its kinda a shame I cant match perfectly.
When you look at it, you see that the information is there.
Someone needs to find a way to extract this information easily from pictures.