Where to take Spec and Gloss out of dDO

mobpapst

Hello guys,

iam new to UDK and i imported an asset of mine and wanted to set up my in dDo created textures for it.

I created a new material and filled it with my textures and i got a diffsue, normal, ao,spec and gloss one.

But iam still confused where to take the spec and the gloss one, the other textures are clear where to put them.

The first one who is not linked is my gloss and the second not linked texture is my spec. Where does i have to put them?



Greetz

Millenia

You're supposed to use PBR workflow, can't use oldschool spec/gloss. Read up on Marmoset's site here:

http://www.marmoset.co/toolbag/learn/pbr-theory
http://www.marmoset.co/toolbag/learn/pbr-practice

It takes roughness maps which work like gloss but inverse (black is polished, white is 100% matte, and metalness input instead of specularity). You'll also want to make sure your normal is Y- when you put it in UE4.

mobpapst

Thankts mate,

that are the answer i needed

Greetz

almighty_gir

one thing to bear in mind with the gloss map that dDo produces (talking about the new quixel suite here), even if you set it up for UE4, the gloss values are all calibrated for blinn-phong and not GGX. you'll want to do some curve editing of the final gloss map to bring it closer into line with the way the materials should read.

MeshMagnet

almighty_gir wrote: »

one thing to bear in mind with the gloss map that dDo produces (talking about the new quixel suite here), even if you set it up for UE4, the gloss values are all calibrated for blinn-phong and not GGX. you'll want to do some curve editing of the final gloss map to bring it closer into line with the way the materials should read.

What's the difference between blinn-phong and GGX?

shirogatsu

MeshMagnet wrote: »

What's the difference between blinn-phong and GGX?

Well, basically:

almighty_gir

yeah that image sums it up in the most basic of terms.

i'd like to preface this post by saying i have no idea how quixel are calibrating their cameras, nor do i have a hard and fast rule for converting from blinn-phong to ggx in terms of math (but it's something i'm working on).

but what i've observed is that if you take the quixel material for any of their metals (dirty steel, tin etc.) and check how they look with a blinn-phong shader vs ggx, they come out looking amazing with blinn-phong but almost concrete-ish with ggx.

this to me says that some conversion needs to be done between the two values rather than simply inverting the gloss map that quixel spits out and using it as roughness.

examples, Blinn-Phong on the left, GGX on the right:

brushed metal


galvanized metal


dirty steel


dusty metal


aluminium


tin


and here's that last one after i added a slight curve adjustment to the gloss map.


and here's the shape of the curve i used.

MeshMagnet

Thanks for the info!

By the way, does the new Quixel 1.3 update account for any of this?

Also, are you adjusting the gloss curve by hand or is there some kind of math involved?

almighty_gir

1.3 doesn't account for it, when it creates a roughness map it just inverts the generated gloss, nothing else goes into it (regardless of whether you choose disney, toolbag disney, or ue4 as your preset).

and i did the curve by hand because my math isn't reliable at this point for an accurate conversion, so i eyeballed it.

josh_lynch

This is a great thread thank you for all the information.

almighty_gir

Quixel have announced that in 1.4 of quixel suite, they will have an updated GGX gloss generator. woop!