PBR Workflow help

deolol

Hey guys. So I've been struggling a lot with the PBR workflow and I simply cannot get results like Marmoset.

I have a few questions:

1. Apparently Specular isn't what it seems in UE4 and shouldn't be touched... so how would I define the reflectivity? - I read it's meant to be defined in roughness/glossy but that confused me further.

2. Is roughness meant to be opposite in UE4? I used OneMinus and it kills reflections.

3. Is there a way to build lighting on selected/specific meshes? I built a scene without lightmaps and previewing it a problem.

Thanks!

Harbinger

1) Spec in UE4 is meant to be a tweak, after you've tuned base color/metalness/roughness. The reflective quality of the surface is based on roughness. There are two main camps for PBR shaders right now: Albedo/Metallic/Roughness and Albedo/Specular/Roughness. UE4 uses the first one, while Marmoset 2 can use either. Albedo/Base Color/Diffuse are all interchangeable terms for all intents and purposes. Roughness and gloss are also interchangeable terms.

2) In UE4, roughness of 0 = perfectly smooth, roughness of 1 = maximum roughness.

3) If you want to emulate Marmoset's lighting without baking lightmaps, you can use a combination of a skylight with an HDR cubemap plugged in, plus regular lights with Movable mobility set.

JedTheKrampus

It's important to note that, while roughness maps and gloss maps define the same type of thing, they are in fact different, and to get one from the other you have to invert it. So if you texture for UE4, you'll use a roughness map, which has black=zero roughness and white=maximum roughness. You can put the same map into Marmoset into the gloss map, but to get it to look right you'll have to tick the 'Invert' checkbox.

EarthQuake

You can actually set up Toolbag 2 to get very similar results to UE4, but you need to use the metalness map workflow, not the spec map workflow. Toolbag supports PBR with both workflows, but UE4 can only use the metalness workflow, the spec map input in UE4 doesn't really do what you would think it should there.

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

^The above is TB specific but has a lot of general information that applies to UE4 as well, like explanations of what the various map inputs do.

RavenTheBird

Like what earthquake say, I currently using Marmoset toolbag 2 for preview for my freelance job for an client using Unreal 4, it is very powerfull tools for artist to understand the PBR workflow.

Btw it is on 30 percent sales now, grab it before too late!

passerby

still a work in progress, but i made a little script for photoshop that should help keeping various masks in sync between materials.

http://www.polycount.com/forum/showpost.php?p=2066071&postcount=1612

TrampledUnderFoot

passerby. that script is awesome! Thanks for doing that, I've been looking for something similar for a while.

passerby

TrampledUnderFoot wrote: »

passerby. that script is awesome! Thanks for doing that, I've been looking for something similar for a while.

When I have time iI want to polish it off, give it some ui buttons, and will realese it in the tech talk section.

narticus

I was wondering if there are any good tutorials for using dDo with UE4 to achieve correct PBR?

That Substance video Hermit posted looks great. I may have to check that program out.

Rooster128

passerby- how do I get this script to work? Is it just a photoshop plugin? And will it work with CS3 by chance?

passerby

@ Rooster, im re-working it all at the moment, and will re-distrubute as a photoshop extension when done, just too busy with work to do so at the moment.

Rooster128

It would be a big help passerby. While I use Substance Designer for a lot of my PBR needs now, I would like to finish things off in Photoshop- and being able to edit multiple layers on the fly like that would be a godsend for a PBR workflow!

passerby

ya will look at it, next week, currently i got a lot of work to do on my current contract.