Essential Blender- P17 pdf

Figure MTD.18: The Map To tab. There are lots of options in the upper set of buttons, and these determine which properties of the material the texture will affect. Mousing over the buttons will bring up a tool tip that describes what each button does. The most commonly used ones are Col, Nor, Spec and Alpha, which we'll look at now. Col: Color. When this button is enabled, the texture works in conjunction with three other controls on this panel: the mixing dropdown (which shows Mix as a default), the Col slider just below it, and the color picker immediately to its left. As this is just the basics, leave the Mix dropdown alone (if you are familiar with mixing modes like Add, Multiply, Screen, etc. from other applications, you'll find all of your favorites there.) The Col slider sets the strength of the texture's affect on the base color of the material on a simple scale - 1 is 100% strength, 0 is 0%. The color picker sets the color that will be used for blending. Nor: Normal. Using textures to vary the normal of a material simulates bumps and detail across the surface. Use this button with the Nor slider to set how deeply the bumps appear. This is commonly referred to as "bump mapping". Spec: Specularity. A piece of metal that has dirt and corrosion on its surface will be rather shiny in clean places, but dull in the dirty spots. Using a texture to affect specularity allows you to simulate this effect. The Var slider determines how much of the texture is used for specularity, from 0 to 100%. It's important to note that properties like specularity (and emit, translucency, alpha, etc.) still use the settings from their main sliders in the Material Buttons as their baseline. This means that if you leave the Spec slider on the Shaders tab at 1, you most likely would not see any effect from the texture. Think of it this way: the Spec slider in the Shaders tab sets the lowest amount of specularity for the material, while the Var slider sets the maximum amount of specularity that will be created by the texture. So, the way to show the greatest range in values of specularity would be to set the Shaders tab Spec slider to 0, while setting the Map To tab Var slider to 1. Alpha: Opacity. The alpha setting works exactly the same way as the Specularity one. Just a reminder, though, to think of alpha as opacity, not transparency, so everything works intuitively. The greatest range of Alpha variation will be achieved by setting the Material tab "A" slider to 0 and the Texture tab Var slider to 1. Make sure to click ZTransp in the Links and Pipeline tab to get an accurate material preview and correct rendering with Alpha. Many of these buttons are not normal toggles, but three-stage toggles. For example, clicking the Nor button once turns it on, while clicking it again leaves it on and turns the label yellow. Clicking once more turns it off. That third state with the yellow label is a "reverse" setting. It uses the texture, but backwards. Under the Nor setting, what would have bumped out now bumps in, while what would have bumped in now bumps out. Likewise, the Neg (Negative) button can be used to invert a texture, and due to complex technical reasons this will not always produce the same result as the third toggle state of one of the property buttons. You are not constrained to using a single property on each channel of the texture stack. Careful selection and adjustment of the property buttons (say, Col, Nor, Spec and Alpha) along with their respective sliders (Col, Nor and Var) can produce complex effects within a single channel. So, with ten channels to work with in the texture stack, you can produce some incredibly complex materials. We've reviewed the four main components of Blender materials (base colors, shaders, reflection/transparency and textures), and explained the most common options relating to them. There is a wealth of additional features and options within Blender's material and texture system that we did not cover, but the basics presented here will give you a good starting point to begin exploring on your own. The Blender 2.3 guide and official online documentation contain explanations for every button and switch in the Blender interface and would be a good companion for users wishing to go beyond these basics. Chapter 9: Materials and Textures in Blender By Colin Litster Blender, like any 3D design suite, is essentially a simulation program. Points (vertices) are placed in a virtual 3D space and these points are joined to form faces. Faces are then lit with simulated lights, and a simulated camera is placed to look at your virtual object. All this has to be done before your simulated object and world can be rendered in all its glory. Blender's Material and Texturing system provides the tools that help you simulate a surface color or property that will turn a boring, gray plastic-looking object into something much more interesting. Figure MTT.1: A photorealistic render from Blender. This could be based on a photorealistic interpretation of a real material or on some artistic style, like a cartoon, or an impressionistic painting. Figure MTT.2: Line illustration render from Blender that simulates a hand drawn look. In other words, Materials and Textures offer an enormous palette of color, style, and effect that can be applied to untextured 3D objects, turning them into a truly inspiring picture or animation. Of course, this means that there is no magic button to press in Blender, or any 3D package, that will automatically produce realistic, or even good-looking, materials. You have to make decisions about many settings, as well as to apply observational and artistic skills. All of these choices can appear daunting to the beginning 3D artist. Indeed, many artists find it difficult to move from more traditional forms of art because of the apparent need to know every aspect of a 3D tool before attempting a still image or animation. Really, though, you only need to know the basics in order to get started. From there, you can build on that knowledge. In this section of the book, we will show you how to quickly simulate a realistic looking material, as well as provide a more general strategy to apply to any material situation. You will also see that you can start to achieve some very good results with only a few tools. The Material Interface For purposes of this tutorial, you are going to use the default Material Screen provided by Blender. Start the Blender application, then use either the keyboard shortcut Ctrl-Left/Right Arrow or the Screens dropdown menu to choose the provided Materials editing screen, which looks like this: Tip: Blender comes pre-configured with a Materials editing screen. Figure MTT.3: The default Materials editing screen. Approaches to Simulating a Real Material Time to get down to creating materials in Blender. For this exercise you will look at how a relatively complex surface material can be created with just a few commands and settings. Also, you'll see an approach to simulating a real material that you can use time and time again to speed up your production pipeline. Don't worry that some commands will be glossed over and given without explanation we're doing a run-through to get you familiar with the basics. In most cases, we will come back to those areas in more detail later, and in the discussion section after the chapter. The best tools you can employ in creating any material are your eyes. Direct visual interpretation of what you are trying to simulate really is the best way to start material and texture creation. For that reason we will start with a surface to which all of us have fairly easy access. Figure MTT.4: A photograph of an office desk. You will start with the simple desk surface, ignoring for now the power adapter and cables. Creating the Object and Setting the Lights Any surface, such as your desktop, either scatters the light toward your eye (this kind of light is called Diffuse), or reflects it directly (called Specular). This means you require some simulated lights to represent the light sources that exist in the real scene. If you need to learn Blender's approach to lighting, you can refer to Chapter 11. Diffuse Light Any surface, such as your desktop, has small crevices, nicks and irregularities that prevent light from reflecting perfectly, as though it were a mirror. In fact, most natural surfaces have so much irregularity that they scatter any light that hits them, so the light that reaches your eye from any point on the surface may have come from almost any direction. Specular Light Some surfaces will also have specular highlights where the light reflects in a more concentrated manner, giving shininess to the surface. Figure MTT.5 The position of lighting certainly affects the way your eye perceives a scene, and for that reason it's important to set up the lights in your Blender scene to approximate the ones from the photograph. Without doing that, you can't get a good read on how to set up your Materials. In the example there are 3 lights. Light 1 represents the outside sunlight that is coming through the window. Lights 2 & 3 are there to represent light bouncing off of the walls and the artificial light source in the room. It is possible to set up very realistic lighting that will accurately mimic the properties of real lights, but it is often better to use quite simple setups that copy the general location and brightness of real world lights. Simple setups mean that you can easily arrange and fine-tune their effect and therefore concentrate on making a material perfect. Figure MTT.6: The desktop with the three lamps. Figure MTT.6.render: The provided scene, rendered with no materials. If you've worked through the modeling and lighting chapters, you should be able to easily make a nice approximation of this setup. For later in the tutorial, you will also need a simple model of the power supply and cables. If you are just working on materials and don't feel like modeling anything right now, you can find the file, called "materials_desktop.blend", with the models and lights preset in the "examples" folder on the included CD. An Approach to Materials Adding a New Material In order to begin, you need to create a new material for the plane surface. Select the plane that is your desktop with RMB. Under the Links and Pipeline tab in the Material buttons is the Add New button. Select this so that a new material will be created for your desktop object. Figure MTT.7: The Links and Pipeline tab, before clicking Add New. . Chapter 9: Materials and Textures in Blender By Colin Litster Blender, like any 3D design suite, is essentially a simulation program. Points (vertices) are placed in a virtual 3D space and these