Handling multiple materials
Video: Handling multiple materialsAssigning multiple materials to an object, needs to take place in another application. We'll use 3DS Max or Maya, for example as our offering application for our assets. We'll model the pieces we need, and assign materials, and unwrap or texture those objects. For example, I've put on the railings multiple materials. When I zoom in here in Maya, we can see by looking in the attribute editor, that there's a material called metal screen. There's brushed bronze, and finally, wood dark for the cap.
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Interested in game making? Start in Unity—a game engine for mobile and desktop games and real-time simulations. Author Adam Crespi shows techniques used in game development with Unity and introduces the basics of scripting and game functionality. First, learn how to import models and textures, organize your project and hierarchies, and add terrain, water, and foliage. Next, Adam explores how to use lighting to bring the game to life, and add rendering, particles, and interactivity. The end result is a sample game with a lush environment, fully animated characters, and some basic interactive gameplay.
- Designing the game
- Creating and transforming objects
- Importing and configuring models and textures
- Setting properties in the Inspector
- Creating the terrain geometry
- Building materials and adding shaders
- Creating GameObjects
- Exploring physics
- Animating objects
- Lighting the scene
- Creating 2D game elements
- Adding special effects
Handling multiple materials
Assigning multiple materials to an object, needs to take place in another application. We'll use 3DS Max or Maya, for example as our offering application for our assets. We'll model the pieces we need, and assign materials, and unwrap or texture those objects. For example, I've put on the railings multiple materials. When I zoom in here in Maya, we can see by looking in the attribute editor, that there's a material called metal screen. There's brushed bronze, and finally, wood dark for the cap.
I've modeled these objects as multiple pieces, and then gone through and assigned materials before combining. Alternately, you can pick select faces, and assign materials in both 3DS MAX and Maya. I've done that for the floor. Putting in the edge loops, for the different places and then selecting polygons and assigning the scored concrete brick, and wood flooring and so on. This way its one object with one collider that looks like different materials. When I export this over, these materials will show up on that object in Unity. I'll go over to Unity and take a look.
Here in Unity, I'll take a look at an object that has multiple materials, and see how it came across. I'll pick that podium object. Clicking once, selects the whole FBX, and one more time selects that unique object. In this case, podium O3. It's got a box collider on it that I had put on earlier, so I could actually walk on the floor without falling through. We can see that the materials come across, just as they were assigned. Concrete smooth, is my outside edges and base. Probably a polygon underneath is lumber one, concrete scored, is the walkway around, and there's the brick for the paving.
Further down, I see wood flooring, and that's the interior floor. For each of these, we can put in a shader and textures. Some have already come across, because they were assigned in Maya. I'll change over the wood flooring to start. When we change an objects material, when it's gotten multiple materials assigned, any other objects that share that material get changed, as well. I'll drop down under wood flooring, for example and pick specular. A specular shader, changes from a lamberate shade to a blend fung shading model, and it has the capacity to shine.
In here then. I get a color with a gloss in the alpha channel. A main color and a specular color, and finally the shininess. What I'll do, so I can see this a little better, is go over to my materials folder in my assets. If you notice by the way, I have an extra blank materials folder in my meshes. That's because Unity created this upon import. I'll go back in meshes, Right Click on that folder, and Delete it. Now, I'll look in my materials folder. And I'll scroll down, to look at wood flooring. The reason that I chose to do this, is that the preview window is larger when looking at the material on its own in the inspector, versus a small thumbnail when it's part of an object's view.
In here, in the wood flooring, in the specular shader, I'm going to pick a different color for the specular color. Clicking on the eye dropper, grabbing it straight from the wood color, then clicking on that color swatch and going lighter. Personally, I prefer to work in hue saturation and value for my colors. Alternately, if you like to work in RGB, you can click on this, little icon here, for the color sliders and change them back and forth. I'll take the value of my, specular color and go brighter and add a little bit of saturation in.
So, when this shines it's got a little bit of a warmth to it. I'll take this color, and just add a little more yellow in the hue. So, it's got a rich bright warmth to it. A little bit of yellow in the floor, not quite so much pink. I'll back off the saturation just a touch, and it looks pretty good. In any of our materials, whether their part of multiple materials on an object, or single materials on one object. Applying a color in the main color, tints that material. So if this floor needed to have, some red to it, for example, we could put that in and it's tinted, overlaid on that base color, because I crafted the texture as I wanted it.
I'm going to pull out the saturation and up the value. So a tint of white, does nothing to that material. We can use that color, to kind of unify materials, especially when they're on one object. That's the wood floor. And now it's a nice, bright, shiny wood. I'll look at the railing, because that's also got multiple materials assigned. I'll press f, to focus in and zoom in further. Here's my metal screen, and I'm going to change this over, from a transparent diffuse to a cut out. This is the polygons, that is on this railing.
And theres one set facing us and one set facing the other way. Because there single sided, I choose to make extra polygons verses making a double sided material. I'll drop down under transparent diffuse. Choose transparent, and instead of transparent diffuse, what relies on the alpha to determine transparency, I'll choose cut out specular. A cut out material is different, as a cutout says, at or below a certain threshold in the alpha the alpha cutoff. That material is exactly gone, and will not shine.
When I zoom in, I can see that perforated metal screen and I'll pull down that alpha cutoff until it shows exactly like I want. With the alpha cutoff all the way down, I can definitely see where the shine is across that material. Pulling up the alpha cutoff a little bit, let's the whole show and let's the alpha channel where it's varied above that value, dictate the shiniest in this brush metal screen. Here's what that alpha channel looks like, so get a clear idea of how this is behaving. In my textors folder under building, I've got screen CS.
In screen CS it looks like a brushed metal. Switching over to the alpha channel, shows that it's a varied grey. So it's got kind of a brushed texture in the shine as well. And then it's exactly black where it needs to be cut out. And this is a tiling pattern mapped at 3 inches square. Looking at the material then. Selecting that object, we can see that the alpha cut off being low, allows that shine to vary from the alpha, and then below there, clip out those holes cleanly. This material is, on this object just in those screen sections, and I've got my brush bronze and other pieces I can adjust.
The last thing I'll do, is change brush bronze over to, a specular shader, and what I typically do for metals, is I'll take that main color, and eyedropper straight from another color I like. Then I'll take this main color, and darken it down, and finally, I'll take my specular color, eyedropper, right from the main color. And boost up that value. So more of the specular color, and more of the diffuse, is evident in the shine, than it is in the main color, which is much darker.
Now I'll boost up the shininess, and I've got my brushed bronze, applied on just the frame sections on this railing. And any other railing that has this material, got those changes as well. Make sure you get your materials aside, per polygon as you want them before you import. Although if you find you need to do, a little bit of a change, and want to re-import that file by exporting the FBX and bringing it over, Unity will update and change just those parts that you had changed. And bring in those materials and adjust them to your heart's content, making it look as real and rich and subtle as you like.
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