This is great. Keeping UVs at 90 degrees never occurred to me but it makes so much sense it seems obvious in retrospect
Unless I'm mistaken, this is how Shadow of the Colossus handles the fur on the Colossi
Awesome breakdown Simon!
Environment artist and material wizard Joshua Lynch talked about the creation of great materials for games.
My name is Joshua Lynch. I landed my first gig with 2XL Games. There I helped develop mobile and downloadable games for various platforms. Since then I’ve had the wonderful opportunity to work on titles such as Defiance, Call of Duty: Advanced Warfare and Call of Duty: Black Ops III. Here’s my take on material creation for videogames.
I will start by gathering as much reference as possible. Typically I will go online and search for reference, and I find if you can find the material nearby and go take your own photos. The reason I say that is when you go outside and see how a surface reacts to the light that’s worth so much more than online reference. Take photos from as many angles and positions as possible, these additional shots will come in handy later on. Once I have a good amount of reference I start working.
Creating The Material
Much like modeling a prop, I work by starting with the large forms and working my way to the finer details. With that said, all of the passes will inform each other, so I try to keep it loose and be open to change and experimentation. Working in Substance Designer is great for this.
When working on any material the first thing I do is create the height and normal map first. I consider this to be the foundation of any material. Much like a real building, the material needs a strong foundation to sit on. While looking at the reference I start to block in the basic pattern of the material in Substance Designer. Now that the pattern is established I start to add in the larger forms. At this point I check it in comparison to a human scale figure to make sure it feels good next to a person. Throughout the creation of any material I am doing two things, checking the photo references and keeping human scale in mind.
Now that larger forms are there I start to add medium details. For this pass that usually means adding surface and edge details. As an example, if its a stone surface, I will knock back or damage some of the edges and add surface movement and undulation. Its very rare for any surface, natural or man made to have a perfectly flat surface. Depending on the surface I will add other details that accent the larger forms.
From here I will start to add micro detail such as surface bumps or pocks for the close up read. I like to think of these details as if you were scraping your fingernail across the surface and what that might feel like. These types of details are the big payoff if the viewer sees them up close.
As well, while I am working I will take care to establish line weight variation and add details to keep the eye moving around the material. You want to have enough detail and variation to make it interesting but you don’t want it to feel overly busy or it will be distracting.
With a strong height and normal in place I will start adding material definition and pull the material apart by establishing basic albedo, and roughness reads. This means establishing if something is dielectric or metal, even if it’s just solid colors, it has a big impact on how the materials read and feel. Depending on the material, hue and value variation should be present but not dominate the material, subtle enough to make it feel realistic but not forced.
With the basic reads established I will do a more detailed pass to really pull the material apart. The goal here is to start to add detail that tells a story. Things like spots of dirt, dried stains, sticky spots are great because they make the surface feel lived in. Leaving areas that feel to flat look boring, but adding detail while keeping it subtle so the eye still moves around and doesn’t focus in on one spot too much. These kinds of details are great and pushing contrast in the color or the roughness to add more interest when the light rolls across the surface goes a long way.
Another step I like to do is add variety to the metal surfaces of a material. For example, a surface that is painted metal and has panels with bolts could have multiple types of metal. The base painted metal could show steel through chipping, the bolts could be lead or nickel, and the panels could be aluminum. These types of subtle changes take a material read a long way to make it feel more realistic and give a variety and richness to the material definition.
Repetition & Details
As far as repetition goes I try to be very aware of this when working in any stage. Gamer’s and artists spot this stuff right away, it is one of the easiest things to pick up on. From the beginning of authoring any material to the end I am checking for repetition. In Substance Designer you can tile a material and then helps. Though, looking at work in Substance can be deceiving, to me, a better gauge is seeing it in game and how it sets in a scene. This is a good practice to get into game early and often.
Adding details to a material can add a lot of character and often times is what makes it feel believable or not. But like anything else, too much added can become noisy and distracting. Some things I do to to avoid repetition is by adding noise and then knocking it back and making it feel selective. By making things appear selective they feel more natural and help sell a believable narrative.
There are some common pitfalls I see in material creation, especially with Substance Designer. When creating something in ZBrush it is frowned upon if it was obvious what brushes or alphas were used. With Substance Designer I feel it’s the same thing, if it’s obvious what node or method was used and just tiled over a surface without care it just breaks the whole read. Additionally, if there is a unified noisiness across the edges, the surface, or both, it feels off. In my opinion, both of these common pitfalls in material creation flattens out a materials by making it feel uniform and unnatural.
Using Substance Designer
I have been using Substance Designer for a little over a year now. It has changed my material creation pipeline completely. Every material I author now is created entirely in Substance Designer, or at least is given an material definition pass through Substance Designer if I bring in a normal map.
The benefits of the tool are numerous. Some of the main features to me are that it is a completely non destructive, highly iterative, and easily adapted to different pipelines. As well, all of the node set ups a easily moved from one material to another, making reuse a natural part of the workflow.
The program works in real time, if you tweak any node you will see how it affects everything without waiting. Let’s say for example I am making a brick wall and I start out with an 8 x 16 pattern and then if I want change it to 12 x 26 pattern it has no issues updating the material. All the texture maps will be updated, like the height, normal, albedo, roughness, and occlusion will all be updated instantly. The frustration of having to update all those maps and hand paint detail over again is gone.
As far as additions to Substance Designer goes I would like to see additional nodes for hard surface workflows, more powerful vector options, and the ability to add text.
For me both Substance Designer and Painter compare to other tools in a few key ways. A lot of artists, including myself, have been using Photoshop for years and have developed a heavy skill set with it. The great thing is that those concepts and workflows can be applied to both Designer and Painter in various ways. For example the concepts of layers, masks, and blend modes all carry over, just in a different form.