could use some help with roughness maps
polycounter lvl 14
Hey guys,
somehow I was stuck working with the old ( non PBR) workflow until now, and I am finally trying to make the switch and could use some help.
The main problem that I have is that I am not sure if I am not missing something when creating the roughness maps. I think I understand the basics - white is smooth/ shiny and black is rough and not shiny and this is inverted for UE4, but I am not sure if what I am doing is correct so I would love to hear how you guys approach this.
This is what I usually do:
I sculpt all my skin details onto the high poly mesh
Then I bake this down to a normal map and from the normal map using NDO i extract something like cavity map so I can use that as a start for my roughness map. This is how this looks out of NDO and inverted so I can use it in UE4 later:
The problem I see here is that this gives me a lot more wrinkles and folds than what I need for the roughness map so after I spoke with few friends I try to remove those by hand just painting it over or using the stamp tool, so then I have something like this that has more even values and just about only surface detail.
after that I try to darken some more the areas that I think should be more glossy and adjust the values so it looks like a skin:
and this is how it looks like in Marmoset:
So how do you guys extract the details that you need for your roughness map? Am I missing or doing something wrong?
Thanks in advance and sorry for all the text
somehow I was stuck working with the old ( non PBR) workflow until now, and I am finally trying to make the switch and could use some help.
The main problem that I have is that I am not sure if I am not missing something when creating the roughness maps. I think I understand the basics - white is smooth/ shiny and black is rough and not shiny and this is inverted for UE4, but I am not sure if what I am doing is correct so I would love to hear how you guys approach this.
This is what I usually do:
I sculpt all my skin details onto the high poly mesh
Then I bake this down to a normal map and from the normal map using NDO i extract something like cavity map so I can use that as a start for my roughness map. This is how this looks out of NDO and inverted so I can use it in UE4 later:
The problem I see here is that this gives me a lot more wrinkles and folds than what I need for the roughness map so after I spoke with few friends I try to remove those by hand just painting it over or using the stamp tool, so then I have something like this that has more even values and just about only surface detail.
after that I try to darken some more the areas that I think should be more glossy and adjust the values so it looks like a skin:
and this is how it looks like in Marmoset:
So how do you guys extract the details that you need for your roughness map? Am I missing or doing something wrong?
Thanks in advance and sorry for all the text
Replies
and here's the gloss map for the face (using GGX reflectivity):
Almost all of the detail in the face comes from a combination of the base normalmap and a detail normalmap. the face has a constant reflective value (0.028) for the entire area.
Huffer- If I make everything darker it becomes a lot shiner than what skin should look like so I am not sure how this would work here. I am actually making this for UE4 so this map is inverted.
Almighty-gir: Thanks for posting this man. I think I am even more confused now
I guess there are different ways of getting there.
I am also not sure If I can use detailed map for this particular project but I will check again.
If I don't use those detailed maps ( I haven't used one yet) would it be ok to add a bit of the surface detail to the roughness map? Since I saw this lates image you posted I have turned it down by 50% and this is how it looks now:
I also started using the skin shader in marmoset for now , so that alone made things look much nicer:
and different lighting condition:
And I have one more question that I am confused about: When you refer to the reflective value, how do I measure that? I am trying to use the color picker but I am not exactly sure what am I looking for. Is it the brightness value?
Thanks again for all the help guys.
edit:
I tired removing all the surface details from the roughness map and added dedicated cavity map and this seems to be working a little better now:
The reason cavity maps are useful is because they help break up what would otherwise be a consistent "sheen" across the skin.
Now I just need to figure out how to measure those roughness values so I can keep everything consistent.
page 9. top right corner...
There is an image of a face with colour coded/numbered regions. on the right is a graph showing the range of gloss and reflectance values measured for those regions. where "m" = glossiness (linear).
the value of 0.028 is just the given average of measured reflectance for skin.
That pdf, and in particular that graph is really useful because it shows you the "plausible range" of values you could use to give your characters variation from each other. HOWEVER - it's also done using a very particular shading model that doesn't match up 1:1 with either blinn-phong or ggx, it is closer to ggx though.