Eye Material: Iris
Textures + Materials = Surfacing
Chapter 3 is all about texturing and material creation - or “surfacing” being the common combined term since they’re tightly related. As you can imagine, the star of the show is the skin material. Skin is one of THE most difficult materials to get right in all of computer graphics. And mostly when it comes to texturing photo-realistic skin, artists rely on sourcing from photos: very high-resolution, polarized photos if possible. This is a powerful method if you can afford to buy such photos.
Thankfully there's an alternative technique which I'm teaching in this course. It only requires Blender, a basic painting ability, and a detailed head model (like the one we made in Chapter 1 + 2)
Hand-painted base color + baked utility maps
Of course before we can paint or bake textures we must layout UVs for our head model, so we’ll do that first. After which we will bake several “utility textures” as I call them. These serve to capture the geometric details of our hi-res sculpt as various image textures. Ultimately they will be layered on top of a simplified skin color base texture which we will paint by hand. This is the only texture we will paint from scratch, if you can believe it. We’ll conclude this first version of the skin material by layering our baked data and adding procedural accents in the material editor.
More to a portrait than Skin
Even though the skin is arguably the main event of this chapter, there’s still a bunch of other materials that cannot be neglected when it comes to photorealism. We’ll take our time with the eyes given their importance for believability. After all if the eyes fail the whole portrait fails. This includes several components like the sclera and iris which we will texture entirely with procedural techniques. It also includes the eye meniscus for that trademark reflection between eyelids and sclera. Then we’ll ease our way into hair with eyelashes and eyebrows. After completing our eye components, we’ll revisit the skin material by meticulously polishing specular reflection, procedural blemishes, and a micro bump detail.
From there it’s a matter of creating materials for our clothing and glasses. When I say we won’t neglect these other non-skin materials, I mean it! We’ll maintain a high-fidelity standard by adding subtle layers of dust and grime to our glasses as well as a highly detailed procedural weave pattern to our hoody along with a fine layer of fuzz to complete the effect.
This chapter increases complexity in the sense that we have to juggle several different concepts from UV layout, to texture painting, to texture baking, to procedural textures, to material properties, to lighting, to hair...at least those are the main ones. So please prepare to be patient through this chapter. If these are all new concepts to you, please watch these courses first:
Chapter 3 - FAQ
1. Can these materials be exported to a game engine like Unreal or Unity?
I'm not aware of a 1:1 export option for complex Cycles materials. In my experience, exporting anything beyond static model data is high-risk.
However the concepts driving the material can certainly be translated over to Unreal, Unity, etc. My recommendation is to essentially rebuild this material in your engine / rendering solution of choice.
2. Are these materials optimized for render efficiency?
There's no way they're optimal. I imagine there's a lot of room to optimize them. However I don't know much about which nodes are more/less efficient in a given situation. I do know that color ramps are apparently very inefficient and I use them all the time 😅
While this makes me think optimizing material nodes could save some render time, I can't say it's every prevented a scene from rendering for me. And a 4-5 min render time for this project at 1080 resolution isn't bad at all (Cycles X).
3. Where can I get free textures and HDRI environment maps?