3D Artist
Apr
8

Texturing tips from Naughty Dog

Tips & Tutorials
by
Steve Holmes

Andrew Maximov takes a break from making Uncharted 4 to bring you some essential texturing advice

Texturing tips from Naughty Dog

Seeing a new console generation is an exciting time for everyone involved in the games industry. We may have all been slightly worried about braving the learning curve for next generation art, but it’s all cleaner and more structured now.

In this workshop we’re going to look at the type of maps you’ll need to produce such next-gen art. We’ll discuss the types of maps you’ll be using in production.

First there’s the Albedo map. Albedo is a natural evolution of the Diffuse texture, but they are not the same thing. While Diffuse is just an image skinned to your mesh, Albedo is a physical property that describes the amount of light bouncing off a surface under neutral lighting conditions. This means that Albedo should be devoid of any kind of specific lighting info, like ambient occlusion or specular highlights.

With the specular map, real-time graphics evolution has made it no longer necessary to use the specular highlight approximation system as we have reflections now. Remember that with specularity, what you define in physically based rendering engines is of facing angles only. Everything has Fresnel reflections, so your surface’s reflectivity is going to increase the more grazing the viewing angle becomes relative to the surface normal. Now, your engine will use either a specular or metallic map.

The metallic map is as straightforward as it sounds. Objects made out of metal are white on this texture and dielectrics are black. Grey values are usually reserved for transition between layered materials, for example on dirty metal. When this map is used, the Albedo of your metals is automatically set to black and their Albedo texture info is used as specular.

Roughness/glossiness is the map where you get to let loose the most. On one side of the spectrum, you have a perfectly sharp reflection and on the other an extreme blur. To sum up the differences from previous generation texturing: your Diffuse map is now replaced with an Albedo map, your specular values from now on will have to be more consistent with measurable real-world values and every surface type is capable of reflection, just like in the real world, making glossiness/roughness dramatically more important in describing material qualities.

As next-gen art grows exponentially, the best response is to increase modularity and reuse. Get ready to start building your material pipeline around masks and material presets. The ideal asset production pipeline will look like: Identify Material Types>Load/Create Material Presets>Blend them together>Apply Wear, Tear, Decals and One-off Details.

Thanks to Andrew Maximov for providing this tutorial. For more of his excellent work, head to his website. Keep an eye out for Uncharted 4, coming to PlayStation 4 in 2016.

As always, let us know what you think of this tutorial on Facebook and Twitter!

And if you missed the issue that this tutorial appeared in, why not pick up a digital edition?
 

Step 01 – Choose your material types for texturing

Texturing tips from Naughty Dog

Identifying types of materials you are going to use is the first step in next-gen texture production. You can be very specific and base your material on a real-world counterpart or go with a more generalised approach. It might be helpful to block out the materials with just plain values and see where it takes you. You can then mask out the materials. This is also a great time to block out some of the masks for your material types inside of your PSD, overlay them with your Normal map and preview the blockouts on the actual asset.
 

Step 02 – Create material presets and add adjustments

Texturing tips from Naughty Dog

The next logical step would be to transform those rough blockouts into fully fledged tileable material presets. They are going to save you a lot of time in the future when producing assets made of similar materials. In the accompanying image you will see what a source material preset might look like. When these are applied to our spheres, you immediately see that we get some nice material definition. This is also a good time to add any adjustments such as colour tints or roughness variation, especially if you are not producing your material preset from scratch, but rather using one you made earlier. You may notice that the metals share a very similar Normal map, which certainly suits us because after we move things around and tile them around, things won’t seem so repetitive. If anything, since all our materials are part of the same object, it is reasonable to expect them to be subject to the same kind of wear.
 

Step 03 – Apply material presets

Texturing tips from Naughty Dog

After you’ve applied the material presets to your model, you’ll see that your asset is 80 per cent there and at a distance it could almost look finished. Once you’re done with the base materials of your object, all that is left is the wear and tear and whatever unique decals and one-offs you might have.
 

Step 04 – Create wear and tear

Texturing tips from Naughty Dog

One of the great tricks that our layered approach lends itself perfectly to is baking the curvature map using the detailed Normal, created by overlaying our preset material’s Normals with the global Normal map. Our curvature map, which is a combination of concavity and convexity maps in one, is baked in Substance. This gives you all the scratches and recesses that match perfectly with your base materials and are very easy to lay down. Select all and press Copy, then hit Q for quick masking mode and paste the mask in. Press Q once more and your mask will be transformed into your selection. Using that selection, paint your scratches in where they would make sense. This way you are still very deliberate in your detail placement, but are still using the generated mask and saving yourself a lot of time. This approach once again will get you 80 per cent there, and from then on feel free to refer to custom texture brushes to finish up the painting of the wear and dirt masks.
 

Dark metals

Texturing tips from Naughty Dog

If you’ve ever dug into the theory behind physically based renderers you would probably know that there are no dark metals in the real world. Not in their pure form, at least. However, through the history of arms production, humans came up with lots of ways to treat metals to be more durable, while unintentionally altering their aesthetic properties. The dark metal that we’re using in this case would have to be blued steel. Bluing is a special process during which a thin layer of magnetite is created on the metallic surface. Magnetite is a mineral with metallic lustre, and that’s why it’s still going to be white on the metallic texture. Always research your materials before production, especially for guns as there are a lot of surface treatments, such as case hardening, bluing, Cerakoting, Teflon coating and so on.