3ds Max PBR Workflow & Materials
polycounter lvl 3
Chances are I'm making things hard for myself lol, but thought I'd explain what I'm doing and then see what people say, I had some other threads on the topic and was reading this article:
That one of the awesome admins here posted. I'm no expert with materials especially for newer workflows, so mainly what I'm after is some clarity with what needs to be separated for ease of compatibility. (Primarily for Sketchfab, CgTrader, Artstation Store, TurboSquid, Gumroad.)
So, I have a scene I'm making with around 20 objects, I'm NOT using Trim Sheet workflow here (I know I could/should have, but didn't want to, not looking for a debate about the pros/cons of it), everything is non-overlapping/unique unwraps, I'm trying to use a PBR workflow with materials from Textures.com. I'm in 3ds Max 2019.
I already had high to low poly Normal Maps baked for every item, as well as Ambient Occlusion maps, I had these plugged in to a standard material just to check everything looked nice using the basic Scanline renderer.
The majority of Materials on Textures.com are Substance ones (I don't have Substance), so I've been downloading the free 1k flat maps and setting them up from there. However, this is where I hit the first snag, I downloaded a gold material, and it came with a height map, there's nowhere to plug this into in the standard material, or the Arnold Standard Surface (which I though was needed for PBR) I read it should be plugged into the Displacement channel but couldn't see that either, after a play around in the Material editor I found the Physical Material which did have a Displacement slot, but actually found the Height map works well plugged in to the bump part of a normal map. Second snag is these materials have their own Normal Map, and as I have another Normal Map already for the nice smooth edges i wasn't sure how this would work. I ended up having a Normal Map plugged into the bump slot, containing the Normal Map for the whole object in the top slot, then in the bump slot, another Normal Map, containing the Normal Map & Height map for the Material from Textures.com.
As confusing as that all sounds it actually produced the desired results in 3ds Max. In Sketchfab, however (I did a test with one object) there's only one Normal map option, and you can't really have a bump, so I was unclear where to put the height map.
I remembered it was possible to bake a normal map onto another normal map, but didn't really want to have to go back and setup high to low polys again, fortunately I found a youtube video that took 5 minutes to setup a recorded action in Photoshop that can combine two normal maps. This produced the exact same result in 3ds Max only now I had the combined Normal map in the top slot, and the height map in the bump slot. In Sketchfab, I have been putting the height map in the Cavity map slot, it doesn't display exactly how it does in Max, but I'm happy enough with the result.
This is all well and good so far as all the objects I've been working on have only had one material, but there are others in the scene with multiple and as the process and amount of maps gets more technical I was hoping to get a bit of direction with the process for some of the other objects. For example I have a neon sign; made up of some iron (which I'll make rusty) scaffolding that holds it up, and the neon tubes that will emit. I'm not sure if I understood it correctly but from the whitepaper I linked above it made it sound like if you have an object made of two or more materials (especially if they're emissive or transparent), then for simplicity/compatibility you are better separating them into their own objects? As most blend methods don't translate well. In addition to the neon sign, I have some objects that are both metal and coloured opaque glass, and I have the same question about those, plus some other object that have 3-4 different materials. I know you can have a map that for example says what part of an object is metal and not, emissive or not, and opaque or not, but am struggling to get my head around if I can do that for these multi material objects, or if I need to separate them.
The ultimate goal is the easiest compatibility for all these other sites to show the thing off at the end. I manually upload everywhere as I find exporters sketchy and unreliable.
Sorry for the essay, thank you for any help.
Replies
Unique/atlas mapping is fine for some things, as opposed to trim sheets. It just depends... what your limits are, your budgets, hardware, software, etc. Different strokes for different assets, mixing matching is totally valid too.
You don't really need Substance Designer to use Substances. Look for the standalone Substance Player app. It will allow you to load SBSAR files that people make from Designer, you can tweak whatever settings they've exposed and spit out bitmaps that you can use in any software.
Standard Material and Scanline renderer are only there for legacy support of old files, these shouldn't be used for new materials. Scanline is old school diffuse-specular workflow. (edit: if you're making game assets, put them in an actual game engine! Unreal or Unity, you pick)
If you want to incorporate tiled textures into an atlas-texture workflow, it's likely best to apply those to your highpoly model and bake them into your atlas texture sheets. Then just use atlas textures.
Displacement isn't used often in PBR workflow. It's mostly a fancy setting, for offline renderers. Most games don't use displacement, it's just too expensive. However it does look nice when rendering still shots of your material balls, or making archviz renders, whatever.
As for combining multiple materials into a single sheet, again that depends. For portfolio use, just concentrate on making things look good, and use some reasonable limits. Studios can teach the game optimization part; it's much more difficult to teach the "looks good" part, so that's usually what gets people in the door.