Join Andy Beane for an in-depth discussion in this video Defining the problem: Tell the story , part of Maya: Advanced Materials.
- So before we begin creating advanced materials, we first need to ask our proposed material questions. Well, not really, but we as material and texture artists need to tell the story of the material we want to create. Everything has a story to tell. In real life, everything has imperfections. So when we create things in 3D, perfection is the fist tell that something is computer generated and not real. Let's take a look at this picture of a fire hydrant. So, what's its story? Well, it lives under a tree, which we can tell by the top of the picture.
But the surface tells me that as well, with the bird excrement on top. Also, it's been in this place for a really long time. I can tell because it's been painted over many times. What does this valve cover tell us? For one, it's handled more than the rest of the fire hydrant. We can tell this because the paint on the cover is more worn and rubbed off. In this next image of the other side of the valve cover tells me a story, with the paint cracking more on this side than the other, which side the sun is on more. See, even a fire hydrant has a story to tell, and it's in that story that we can get our details for our material.
So what is material, and what makes one surface different than another? Well, in most materials, there are six different attributes we can manipulate in 3D applications. The first is color. It's just that. What color or colors is your object? The second is bump. What does the surface feel like? The third is reflections. Is it reflective like a mirror or just slightly reflective like a ceramic cup? Specular highlights. Now, this is a 3D application-specific render option that will simulate highlights that in the real world are just reflections of bright lights.
Transparency. Is your object glass or is it slightly opaque plastic? And self-illumination. This would be like this lamp shade with the light turned on or a computer screen that's turned on and having light come from the inside of the object. So before creating a material for an object, you first need to interview it. You need to define what the object is. Is it metal, or wood, or plastic, or glass, or paper, or even water? And in the real world, most objects are more than one material, so you will want to define the specifics about that material.
What else is it made of? Like this street sign; it's metal, but it's covered in reflective paint, and in this particular street sign, has a lot of rust on it as well. This new cabinet; it's wood covered by latex paint, now rather shiny form the paint properties and not the wood. This old cabinet; it's wood covered by latex paint again, but worn down in spots, so now we can see the wood underneath. The wood grain is also compressed now with age and will be a bit more shiny than a new wood cabinet, like this new wood cabinet.
The wood grain is not yet compressed and will have more of a glossy sheen across it. And sticking with wood, let's take a look at this pencil. Wood, paint, graphite, they all have very different surface properties. So the last part of the story we need to tell is what can change a material's surface properties? Well, the first thing is light. With time it will desaturate color of just about everything. Age and time by itself will decompose an object. Look at mummies in tombs. They're stored in these dark spaces with nearly no humidity, and with enough time, they too will decompose.
And lastly, the most destructive of all, human touch. Human touch can instantly change the surface properties of any material. Just by touching glass with our fingerprints, we've made a change to glass' properties. Alright. So once you know all about your material, the very next, very important step is to find real-world references, having multiple references inform your eye so that you can better tell the story of that object.
Andy Beane includes two methods for creating advanced Maya materials. He starts with smaller, easier materials that can be composited together. He then shows how to combine these same materials in an all-in-one-method for rendering, and evaluate the pros and cons of both techniques. Chapter 3 demonstrates the subsurface scattering (SSS) material in mental ray, which will strengthen your material toolbox, and shows how to composite the results in After Effects.
- Collecting and creating reference material
- Using simple materials vs. a large complex shader network
- Setting up the scene
- Creating alpha materials
- Compositing individual materials
- Putting it all together in one material
- Subsurface scattering with mental ray materials