Pbr microsurface (gloss) workflow help needed.

BradMyers82

I have been trying to find info on this, and looking at other peoples maps, but I’m just not sure.
Can anyone fill me in on a general workflow for creating the microsurface (gloss) in a pbr system?

I was thinking you should first set base values, then overlay the cavity, multiply the ao on top then do any kind of detail/grunge work to break shit up.
Is this a correct workflow or is the cavity and ao stuff I mentioned going to make it incorrect?

almighty_gir

do not overlay anything. gloss/roughness really is as simple as: paint it white for one end of the spectrum and black for the other, and fill in the middle with varying values.

gloss/roughness is the one area where there's no real measurement involved, it's where artists can truly express themselves for the most part.

now obviously there are some exceptions. you'll never have a glossy brick for example.

if you try to bake in information like cavity, all you're doing is saying "this area is incredibly glossy/rough (depending which you're using)".

so yeah... have fun with your gloss maps! they're awesome!

Swizzle

almighty_gir wrote: »

now obviously there are some exceptions. you'll never have a glossy brick for example.

Stop it! Bad tech artist! Go sit in the corner and think about your life decisions!






Seriously, though, Lee's spot-on.

Gloss maps are where the life of your material comes from. Most stuff reflects more or less the same amount of light (unless it's something like rough coal or a diamond), so you can get away with really simple or even nonexistent spec maps. Your gloss maps, on the other hand, should have a lot of variety in them unless you're working on something that's supposed to be very new.

You should ABSOLUTELY NOT overlay things like AO and cavity on your gloss maps, as Lee mentioned. Cavity and AO are supposed to simulate where less light is hitting the surface of an object, but they should never affect how glossy/rough a surface is. You can certainly use them to help make masks for where you want to paint on your gloss map, though; AO is great for masking off areas that you want to put some accumulated dirt and grunge into.

BradMyers82

ok, this is exactly the feedback I was looking for, thanks a lot guys!

Yea, I had a feeling I was doing something dirty when I started to overlay those maps. haha, glad you guys cleared that up for me. I'm sure I have seen other people do it tho, which is why I was confused.

Swizzle: your advice about using the AO for masking will really help a lot. didn't think of that. Def. going to use that to hit edges with details and stuff.

EarthQuake

Another important thing to note is that depending on the engine/shader, the value range may be inverted. UE4 for instance uses a "roughness" map, so white values = rough while black = glossy. Toolbag 2 uses a "gloss" map, where black = rough and white = glossy. This is simply a matter of inverting the map depending on which engine you're using though.

BradMyers82

Thanks EQ, I didnt know that. I thought it was universal across all engines.

EarthQuake

Nope, to make matters worse, I've heard of engines that call it a roughness map but map 0=rough an d 1=glossy as well. Anyway, its really not an issue once you know which input your engine expects.