Blender灯光和渲染第四章.doc

Outdoor Scene: Adding Materials 室外场景：添加材质Now that weve lit our scene properly, we can begin to take a look at the next step of the processadding and editing materials. Materials in Blender are what give meshes a particular look or feel. This includes:现在我们已经适当的点亮了我们的场景，我接下来将开始到下一步-添加和编辑材质。材质在Blender是给网格一个特定的外观。包括： Color 颜色 Texture 纹理 Shading 阴影 Reflections 反射We are going to take a look at these as well as some other properties associated with materials and textures in Blender. In this chapter, we will:我们将看一看除了上面的这些还看看在Blender的材质和纹理其它的属性。我们将学习： Look at how Blender deals with materials How to create and edit material properties Various algorithms Blender uses to render materials How to create semi-transparent and reflective objects How to create materials specific to our tricycle scene 看看Blender如何使用材质 如何创建材质和编辑材质属性 Blender使用不同的计算方法创建渲染材质 如何创建半透明和反射物体 如何创建我们创建的三轮车材质Creating a new material 创建一个新的材质There used to be multiple approaches to creating a new material in earlier versions of Blender, but in v2.5, the process has been reduced to one menu to eliminate any confusion or unnecessary use of interface space.在Blender早期的版本使用了多种创建一个新材质的方法，但2.5版本后已经缩减为一个菜单以防止造成不必要的混乱或不必要的界面。Remember when we learned that the menu buttons for the Lights menu and the Material menu are toggled depending on whether a light or a mesh is selected in our 3D scene? We are going to take a look at the Material menu this timeif you select any mesh in the scene, you should see that the Material menu becomes accessible.记得我们前面学习的Lights和Material按钮的切换取决于在我们的3D场景选择的是灯光还是网格物体？我们这时去看看Material菜单如果你在场景选择了任何的网格物体，你应该看见材质（Material）菜单被激活。Taking a closer look at the Materials menu 仔细看看材质菜单 Before we can effectively create materials in Blender, we need to understand what settings control what aspect of rendering and why we should use each. Otherwise, there wouldnt be much point in randomly selecting buttons, hoping that eventually one of them will work. When we see the Material menu for the first time, we see a blank materials list and a material add/selection button.在我们有效的在Blender创建我们的材质前，我们需要理解什么设置控制什么渲染表现和为什么要使用这些设置。否则它们不指明随意的选择按钮，希望它们中的一个将工作。当我们首次看看材质菜单，我们看看空白的材质列表和材质add/selection按钮。The Material menu, at an initial glance, looks like the following screenshot:初识材质菜单，如下图：Go ahead and press New because we dont have any materials in our scene yet. We need to create one to take a look at the options available. Once weve created a material, our menu changes to look something similar to the following screenshot:因为我们的场景还没有任何的材质，继续点击New按钮。我们需要点击创建一个材质。我们创建材质后，我们的菜单会改变成相似下面图像：The Material menu looks like the following screenshot after a new material is created:材质菜单如下图并有一个新的材质被创建：Now we have a number of settings available to us that we can use to customize our material. 现在我们有一些可用的设置让我们来自定义自己的材质These settings include:这些设置包括： Material name and type 材质名和类型 Preview 预览 Diffuse and specular 漫反射和高光 Shading 着色器 Transparency and mirror 透明度 Subsurface scattering 次表面散射Material name, type, and preview 材质名字，类型和预览In order to keep our materials organized in our 3D scene, we can give each a unique name that describes what the material is. By default, Blender named our material Material. Not very unique or interesting is it? Go ahead and change it to test_materialno, it may not be much more intuitive, but it better explains the purpose of our material, which is the goal.为了便于在我们的3D场景组织我们的材质，我们给每一个材质一个独一无二的名字。默认的Blender命名我们的材质为Material。既不独特也不引人注目？继续改变材质名为test_material，它也许不够有直觉力，但它能够很好的表示我们材质的目的和目标。Blender provides us with four available material typestwo of which are new additions as of Blender v2.5:Blender为我们提供了四个可用的材质类型-两个是Blender v2.5新添加的材质类型： Surface 表面 Wire 线框 Volume 体积 Halo 光晕The Surface mesh window looks like the following screenshot:表面网格窗口如下图：Surface is the default material type. Its a typical 3D surface mesh, just like you would fnd in any 3D program. Most often, this is the type that we will use in our 3D scenes, because it most effectively resembles the surface of most objects in the real world.表面（Surface）是一个默认的材质类型。它是一个典型的3D表面材质，你可以在任何的3D程序找到它。它是在我们3D场景中最常常使用的材质类型，因为它最有效的表现真实世界的大多数材质。The following image is the peanut character we looked at when discussing light rigs rendered with white material set to Surface type:下图我们所看到的花生角色是使用了白色的表面材质类型：Wire renders our mesh as a wireframe model, instead of a solid polygonal model like the Surface material type does.线（Wire）渲染是以一个线框的方式渲染我们的模型，相反一个实心多边形看起来像表面材质那样。Rendering in wireframe is useful to showcase how an objects mesh is laid out for a portfolioa clean mesh is a good mesh.以线框渲染来呈现是非常有用的一个物体网格是怎么显示的-一个干净的网格是一个好的网格。The following image is rendered with white material set to Wire type:下图图像使用白色的材质并设置线框类型：The next available material type in Blender is a new additionVolume. This is an attempt at creating volume primitives to compete with those of programs such as Autodesk Maya. Although still at an early stage, this material type can prove very useful in the right situations.下面的可用材质类型在Blender新添加的体积。这试图创建一个体积原始物体来和像Autodesk Maya这样的程序来竞争。尽管它还处于早期阶段，这个材质在正确的环境是被证明是非常有用的。When this type is selected, Blender uses the mesh as a cage, and creates a volumetric fog effect within the parameters of this cage. This effect is well achieved in the following image, which is rendered with white material set to Volume type:当这个类型的材质被选择，Blender以整个网格作为一个整体空间，在这个空间界限里面创建一个体积雾. 这个效果在下面的图像被很好的完成，使用白色材质并设置体积类型渲染：The fnal material type found in Blender is not newthe Halo material type has been around nearly as long as Blender has. This material is extremely useful in creating a glowing effect.在Blender最后介绍的一个材质类型并不是新的-光晕材质在早期的版本就已经存在。这个材质对于创建一个发光效果是非常有用的。Although the default settings arent great and it takes some major tweaking to get reasonable results, the Halo material type is used often and can prove worth the effort. The following is an image rendered with white material set to Halo type:尽管默认的设置的效果不是很好的，但它有一些主要的调整可以得到很好的效果，光晕材质类型是常常被照明为非常有用的效果。下面的图像使用了白色材质和设置光晕类型：Preview 预览Notice how the image under Preview changed as we looked at the different material typesthis is because the Preview image updates itself automatically to simulate what the selected material would look like on various meshes, including:注意预览下面的图像是如何随着我们选择的材质类型而改变这是因为预览图像随着选择的不同的网格模拟材质，包括： A fat plane 平面 A sphere (which is the default preview mesh) 球体 （默认的网格预览） A cube 立方体 A Suzanne mesh 猴子网格 Particle strands 粒子线 Environment-mapped sphere 环境球Suzanne is an inside joke of the Blender community. During development of one of the early versions of Blender, one of the developers modeled a monkey head and included it in the primitive object options alongside the usual cube, plane, sphere, and so on. The monkey head has since been dubbed Suzanne and has been included in every Blender release since.Suzanne是Blender社区里的玩笑。在早期版本的Blender 开发中，其中一个开发者建立了一个猴子头并包含在初始物体和常用的立方体，平面，球体等等放在一起。猴子头那时起被称为Suzanne并包含在以后发行的每一个版本中。We may choose to use a different preview mesh depending on how our materials are mapped onto our objects. Well take a close look at when to use each mesh when we talk more about textures.我们也许会选择不同的预览方式取决于我们的材质是怎么样投射到我们的物体的。我们将仔细看看我们的纹理Diffuse and specular 漫反射和高光Every object in the real world has diffuse and specular properties. The term diffuse refers to the overall color produced when light is reflected, refracted, and absorbed by an object. Specular simply refers to the highlights of an objectmetallic and plastic materials tend to have higher and harder specular properties than something like cardboard or a woolen blanket. These highlights are really more of a 3D trick that actual highlights. More often than not, highlights in a real photograph are the result of the light coming directly from a light source, such as a window or light bulb, and bouncing straight into the viewers eye. The specular value controls how that effect is supposed to behave in our render.在真实世界的每一个物体都具有漫反射和高光属性。术语漫反射（diffuse）参考当光被物体反射，折射和吸收后的整体颜色。高光（Specular）参考了一个物体的高光金属和塑料材质比起卡纸板或一张毛毯有更强烈的高光。这些高光比起真正的现实世界的高光只能算是3D戏法。高光往往在一个真实的拍照是直接来自光源的结果，如窗口或灯泡的光反弹后直接进入观察者的眼睛。高光（specular）的值控制如何表现我们期望的渲染。Take this clock for exampleas we can see, there is a very high specular highlight. This is why the highlight on the black plastic border is so sharp. If this clock were to have a lower specular value, the highlight would neither be as sharp, nor as prominent.拿我们看到的这个钟表的例子，有非常高的镜面高光。这是为什么黑色的塑料边界高光那么锐利。如果这个钟表设置为一个较低的高光值，高光将既不锐利，也不突出。Diffuse shader models 漫反射着色模型Blender supports numerous algorithms that we can use to render diffuse materials. Each can be used to create a different effect, from the most abstract to the hyper-realistic. These models include:Blender支持多种计算方式让我们能够用来渲染漫反射材质。每一个都能够被用来创建一个不同的效果， Lambert 朗伯材质 Oren-Nayar 粗糙表面 Toon 卡通 Minnaert 背部反射 Fresnel 菲涅耳反射We are only going to concern ourselves with the Lambert shading model, because its one of the most versatile algorithms that Blender provides and can be applied to almost any situation. If youre interested in learning more about how the other shaders work and why Blender includes them, feel free to visit /index.php/Doc:Manual/Materials/Properties/Diffuse_Shaders.我们仅仅需要的是关心Lambert材质，因为它是Blender提供的应用最广几乎适合所有的材质模拟。如果你有兴趣阅读更多的关于其它着色器（shaders）是如何工作和为什么Blender包括它们，请免费参阅/index.php/Doc:Manual/Materials/Properties/Specular shader models 漫反射着色器。In the same way diffuse shader models calculate how the diffuse color will appear on a material, specular shader models control how the specular color, or highlight, of a material will look.和漫反射着色器一样漫反射颜色是如何呈现材质的。高光着色器控制高光颜色是如何表现的。These models include: 这些模型包括： CookTorr Phong Blinn Toon WardIsoExperiment with each of these and see what results you getwe will focus primarily with Blinn and Phong specular highlights.每一个的对应结果如下，我们主要是研究Blinn和Phong高光反射。Shading 着色器The Shading settings deal directly with how light interacts with our material. Emit dictates how much light the material gives off. In computer graphics, its common to only take into account the effect direct light has on an object, and unless we use ambient lighting, Blender wont take any indirect light into account. With the Emit parameter, we can use meshes in our scene as lights as well, and because Blender needs ambient lighting to render this light, we get the added value of indirect lighting as well. Ambient determines how heavily the material is affected by light from the surrounding environment. Translucency tells Blender how much light can pass through the material.着色器设置是直接处理灯光和我们的材质是如何相互作用的。发出的命令是给出多少材质的光。在电脑图形，它只需说明直接光照在物体的效果，除非我们使用环境光，Blender不计算任何的直接光照。使用发出的参数，我们可以在我们的场景像使用灯光像网格那样，因为Blender不需要环境光渲染这个灯光，我们添加间接的灯光。环境决定多少材质受到来自周围的灯光的影响。Translucency告诉Blender有多少的灯光传给材质。There are also three checkboxes that we can activate if we choose: 我们有三个可用的复选框选项： Shadeless Tangent Shading Cubic Interpolation Shadeless, as we can guess, tells Blender to throw away everything else we tell it about the color of our material and render the object with a single color value. This fattens out the object immediately, leaving the outline to be the only discernable part of the render.Shadeless,正如我们所猜想的那样，告诉Blender不使用其它的材质只使用单一的颜色来渲染物体。渲染快，因为仅仅渲染物体的外形。Tangent Shading considers the direction of the surface tangents when renderingit typically results in an anisotropic highlight. Tangent Shading 在它渲染时考虑了表面的切线方向，它最典型的结果是一个anisotropic高光。Cubic Interpolation tells Blender to use a cubic algorithm when rendering an image, compared to the default linear algorithm.Cubic Interpolation告诉Blender使用一个立方计算法来渲染一个图像，相比于默认的线性计算法。Transparency and mirror 透明度和镜像Transparency and mirror are extremely useful when working with glass and metal materials. Both features have numerous parameters that we can use to adjust how we want our material to look.透明度和镜像当用来制作玻璃和金属材质时是非常有用的。它们都有非常多的参数帮助我们校正我们的材质看起来是怎么样的。Configuring the transparency settings透明度参数设置To enable transparency for a material, select the checkbox next to the Transparency menu heading. Blender approaches transparency in two ways:要开启透明度选项，勾选Transparency菜单前面的复选框就可以。Blender有三种计算透明度的方法 Mask 遮罩 Z Transparency Z-透明度 Raytrace 光线追踪Z Transparency uses something called an alpha buffer to calculate the transparency of an object. Blender calculates this type of transparency by mixing colors of objects overlapping each other. For example, if a semi-transparent red sphere was placed in front of a yellow one, we would see the intersecting section take on an orange hue.Z-透明度使用在叫阿尔法缓冲来计算一个物体的透明度。Blender通过每个物体相互重叠的颜色来计算这个类型的透明度。例如一个semi-透明度的红色球体重叠在另一个黄色的球体前面，我们看到交叉部分的颜色是橙色。This algorithm isnt by any means physically accurate and doesnt require much computing power to create. Because of the amount of tweaking it would take to get right, we are only going to work with raytraced transparency. Like other raytraced features in Blender, raytraced transparency is mathematically calculated and physically accurate, requiring more computational power and longer render times. 这个算法并不精确的和不需要很强大的计算功率。因为它需要我们不断的调整数值来得到正确的值，而我们常常使用另一种的光线追踪的透明度。像在Blender的其它光线追踪的功能，To enable raytraced transparency, select the Raytrace button at the top of the Transparency settings.要开启光线追踪透明度，选择在Transparency设置的Raytrace按钮。We immediately see a long list of settings we can configurelets take a quick look at each of them.我们立刻可以看到一个设置列表让我们看看这些的每一个设置。 IOR (Index of Refraction) IOR 折射指数 Filter 滤镜 Falloff 衰减 Limit 限制 Depth 深度 Gloss 光泽IOR, or Index of Refraction, is one of the most important settings we will deal with when working with transparency. Everything in the real world that has some degree of transparency has an index of refraction. This is simply a number that dictates how far light is refracted when it passes through the object, resulting in the distortion of objects behind it. Take a look at the image of the shot glass belownotice how the pattern is warped when you look through the glass.IOR都叫折射指数，是一个我在处理透明工作中最重要的其中一个设置。在真实的世界每一个带有透明度的物体都有一个折射指数。这是一个简单的当光透过物体有多少光杯反射，结果是看物体后面的东西将会产生扭曲。看下面的玻璃图像注意当你透过玻璃看到的图案是弯曲的。Jenny Downing /photos/jenny-pics/2872292856/Filter controls how much of the materials diffuse color is blended with the materials transparency. This simulates light absorption in materials like glass. 滤镜（Filter）控制多少的材质的表面颜色被混合到材质的透明度。模拟灯光吸收的材质像玻璃。With an Index of Refraction of 1.55 (the IOR of consumer-grade glass), the image on the left is rendered with a Filter value of 0, while the image on the right is rendered with a Filter value of 0.5.折射指数1.55（玻璃的IOR值），在左边的图像使用滤镜（Filter）数值为0，而右边为0.5.Falloff deals with the Filter setting, telling Blender how much blending to actually do between the material color and the transparency values. By default, Blender uses a Falloff value of 1.0, which means that the light rays lose power at a linear, constant rate. The effect this value has on the image is so subtle that unless it interacts with another parameter in the scene in a specifc, user-defined way, theres no real need to change it.衰减（Falloff）处理滤镜（Filter）的设置，告诉Blender在材质颜色和透明度的值实际的混合值。默认的是衰减值为（Falloff）1.0，意味着光线是以线性比率丢失的，With a Filter value of 0.5, the image on the left is rendered with a Falloff value of 1.0, while the image on the right is rendered with a Filter value of 0.1.Filter的值为0.5，左边的图像以Falloff值0.1渲染，而在右边的图像是0.1.Limit sets the maximum distance that light can travel through a transparent material before being completely filtered. A value of 0 disables this feature.限制设置最大灯光在完全被过滤掉前能够通过透明材质的距离。数值为0意味着这个功能失去作用。With a Filter value of 0.5, the image on the left is rendered with a Limit value of 0, while the image on the right is rendered with a Limit value of 3.0.当一个Filter值为0.5，左边的图像使用Limit的值为0渲染，而右边的图像使用Limit的值为3.0渲染。Depth deals with the number of acceptable inter-refractions calculateda higher value here will result in a higher resolution transparency effect. For good results at a reasonable render time, a Depth value of 6 works well, but this can range anywhere between 1 and 10, which is shown below. Note how the lower Depth value creates a dark shadow in the middle of our transparent objectthis is due to the lack of refection resolution and can be eliminated with a higher Depth value.Depth处理接受的反射次数高的值将有高的透明效果。要好的效果和合理的渲染时间，Depth的值为6就非常好，但这个范围最好是在1到10之间的任何一个值。注意多低的值将在我们透明的物体产生一个黑色的阴影这取决于缺乏足够的反射资源和可以提高Depth的值消除这个问题。The last aspect of transparency that we need to look at is the Gloss settings. Gloss allows us to render fuzzy refractions and refections, which is extremely useful when rendering materials like frosted glass. Its a bit sensitive thoughmany times, reducing the Amount value to 0.95 is more than enough (1.0 renders no gloss effect).透明度最后的是需要Gloss设置。Gloss允许我们渲染模糊的折射和反射，渲染霜冻的材质时非常有用。它有一点不好太多的时间，减少Amount的值到0.95已经足够（1.0渲染没有gloss效果）。The image on the left is rendered with a Gloss value of 1.0, while the image on the right is rendered with a Gloss setting of 0.8.左边的图像使用Gloss的值为1.0渲染，右边的Gloss的值为0.8渲染.Configuring mirror settings 设置镜像（mirror）The Mirror menu, like the Transparency menu, has an array of settings we can use to customize our reflections. Unlike the Transparency feature, though, reflections in Blender are purely ray tracedunless, of course, we use a texture map on the materials refection channel, but thats something completely different all together. 镜像（Mirror）菜单，像透明菜单，有一系列的设置我们可以用来自定义我们的反射。不想透明（Transparency），通过