Blender 灯光和渲染基础(第四章).doc

翻译Outdoor Lighting: Setting Up Our Scene室外光源：Lighting techniques are highly dependent on the location of the scene at hand. The approaches to lighting an outdoor scene are radically different from the techniques used to light an indoor scene. Knowing these differences and when to use each is important when aiming for a believable result. We will take a look at:灯光技术高度取决于在场景的位置。室外灯光和室内灯光的处理技术是完全不同的。知道这些不同是很重要的对于我们创建一个真实可信的渲染结果。接下来我们将看看以下内容： Establishing a workflow 确定工作流程 Things to consider when lighting a scene 照亮一个场景应该考虑的事情 Adding and editing lights in Blender 在Blender添加或编辑灯光 How to use layers to increase the quality of our render 怎么使用层来提高我们的渲染质量 What habits are good when lighting and why 那些习惯是好的和为什么是好的Getting the right flies 获取文件Before we get started, we need a scene to work with. There are three scenes provided for our usean outdoor scene, an indoor scene, and a hybrid scene that incorporates elements that are found both inside as well as outside. All these files can be downloaded from /lighting-and-rendering/.在我们开始前，需要一个场景文件。这里为我们提供了3个场景文件-一个室外场景，一个室内场景，和一个包含室内和室外的混合场景。所有的文件可以从这里下载/lighting-and-rendering/.The file we are going to use for this scene is called exterior.blend. This scene contains a tricycle, which we will light as if it were a product being promoted for a company.我们将要使用的场景文件叫exterior.blend。这个场景包含一个三轮车，我们将假设它是一个公司的宣传产品来设置照明布局。To download the files for this tutorial, visit /lighting-and- rendering/ and select exterior.blend.要下载本教程的文件，请访问 /lighting-and- rendering/ and select exterior.blend.Blender render settingsIn computer graphics, a two-dimensional image is created from three-dimensional data through a computational process known as rendering. Its important to understand how to customize Blenders internal renderer settings to produce a final result thats optimized for our project, be it a single image or a full-length film. With the settings Blender provides us, we can set frame rates for animation, image quality, image resolution, and many other essential parts needed to produce that optimized final result. Because we are going to use the same render settings for all projects in this book, we are going to take a look at how to set those values now.在电脑图形中由3D图像通过计算得到2D图像的过程叫渲染。它是很重要的对于我们理解如何设置Blender内部渲染器来优化我们的项目产生最终的渲染结果，一个单一的图像或完整的影片。在Blender里，我们能够设置动画帧速率，图像质量，图像分辨率，和其它优化我们的产品最终结果必不可少的设置。因为我们将在本书中所有项目使用一样的设置，让我们看看怎么设置这些值。The Scene menu 场景菜单We can access these render settings through the Scene menu. Here, we can adjust a myriad of settings. For the sake of these projects, we are only going to be concerned with:我们可以通过场景菜单访问这些渲染设置，在这里有大量的参数设置，但我们对于我们的这些项目，我们仅仅需要考虑的是： Which window Blender will render our image in Blender将在那个窗口渲染图像 How render layers are set up (we will discuss this in more detail later on) 怎么设置渲染层（我们将稍后讨论更多的细节） Image dimensions 图像大小 Output location and file type 输出路径和文件类型Render settings 渲染设置The first settings we see when we look at the Scene menu are the Render settings. Here, we can tell Blender to render the current frame or an animation using the render buttons.首先让我们来看看场景菜单的Render设置。在这里我们可以通过使用按钮告诉Blender渲染当前帧或一个动画。We can also choose what type of window we want Blender to render our image in using the Display options.我们可以在Display选项选择Blender渲染一个图像时，使用哪一种窗口类型。The fist option (and the one chosen by default) is Full Screen. This renders our image in a window that overlaps the three-dimensional window in our scene. To restore the three-dimensional view, select the Back to Previous button at the top of the window.第一个选项是全屏（默认）。渲染图像时将覆盖我们的3d窗口。要返回到3D窗口视图，选择顶部的Back to Previous按钮.The next option is the Image Editor that Blender uses both for rendering as well as UV editing, which we will cover later. This is especially useful when using the Compositor, allowing us to see our result alongside our composite node setup. By default, Blender replaces the three-dimensional window with the Image Editor.接下来的是Image Editor,可以用为渲染窗口还可以用UV 编辑，我们稍后将讲到。这个选项在我们合成时候非常有用，允许你边查看渲染结果边编辑节点。默认的渲染图像将覆盖住3D视图窗口。The last option is the option that Blender has used, by default, since day oneNew Window. This means that Blender will render the image in a newly created window, separate from the rest of the programs interface.最后一个选项是New Window。它在Blender渲染图像时将创建一个独立于软件界面的新窗口。For the sake of these projects, were going to keep this setting at the default settingFull Screen.对于这些项目，我们将保持默认的设置- Full Screen。Dimensions settings大小设置These are some of the most important settings that we can set when dealing with optimizing our project output. We can set the image size, frame rate, frame range, and aspect ratio of our render. Luckily for us, Blender provides us with preset render settings, common in the film industry:这里对于项目有一些重要的设置。我们可以设置图像尺寸，帧速率,和我们渲染的方向率。幸运的是，Blender为我们提供了电影工业常用的渲染设置： HDTV 1080P HDTV 720P TV NTSC TV PAL TV PAL 16:9Because we want to keep our render times relatively low for our projects, were going to set our preset dimensions to TV NTSC, which results in an image 720 pixels wide by 480 pixels high. If youre interested in learning more about how the other formats behave, feel free to visit /wiki/Display_resolution.为了使我们的项目保持相对较低的时间，我们将选择预置的TV NTSC,选项，这个渲染的图像宽是720像素而高是480像素。如果你对其它的格式感兴趣请访问/wiki/Display_resolution.Output settings 输出设置These settings are an important factor when determining how we want our final product to be viewed. Blender provides us with numerous image and video types to choose from.这些设置是很重要的对于产品最后的大小。Blender提供了许多的图像和视屏的设置供选择。When rendering an animation or image sequence, its always easier to manually set the folder we want Blender to save to. We can tell Blender where we want it to save by establishing the path in the output settings. By default on Macintosh, Blender saves to the /tmp/ folder.当渲染一个动画或图像序列，手动设置Blender想要保存的文件夹是很容易的。我们可以设置Blender的输出路径。在苹果系统，Blender默认保存在/tmp/ 文件夹。Now that we understand how Blenders renderer works, we can start working with our scene!现在我们已经理解了Blender渲染是如何工作的，我们可以使用我们的场景开始工作。Establishing a workflow 确定工作流程The key to constantly producing high-quality work is to establish a well-tested and efficient workflow. Everybodys workflow is different, but over the course of the next few chapters, we are going to follow this series of steps:生产高品质的工作的关键确立一个可测试的和有效的工作流。虽然每个人的工作流程是不同的，但在接下来的章节，我将跟随以下的步骤：1. Evaluate what the scene we are lighting will require. 确定我们的需要照亮什么场景2. Plan how we want to layout the lamps in our scene. 规划我们需要怎么在我们的场景布局灯光3. Set lamp positions, intensities, colors, and shadows, if applicable. 设置适当的灯光的位置，强度，颜色和阴影4. Add materials and textures. 添加材质和纹理5. Tweak until were satisfied.调整直到满意Evaluating our scene 评估我们的场景Before we even begin to approach a computer, we need to think about our scene from a conceptual perspective. This is important, because knowing everything about our scene and the story thats taking place will help us produce a more realistic result.在我们开始电脑工作前，我们需要考虑场景的概念视图。因为知道我们场景和故事的一切是重要的对于放置我们的灯光帮助我们产生更真实的效果。To help kick start this process, we can ask ourselves a series of questions that will get us thinking about whats happening in our scene. These questions can pertain to an entire array of possibilities and conditions, including: Weather 天气 What is the weather like on this particular day? What was it like the day before or the day after? 这个特定的日期的天气是怎么样的？昨天呢？明天呢？ Is it cloudy, sunny, or overcast? Did it rain or snow? 它是多云的，晴天或是阴天？是下雨还是下雪的？ Source of light 光源 Where is the light coming from? Is it in front of, to the side, or even behind the object? 灯光来自哪里？是前面，还是侧边或是物体的后面？ Remember, light is reflected and refracted until all energy is absorbed; this not only affects the color of the light, but the quality as well. Do we need to add additional light sources to simulate this effect?记住，灯光的反射和折射直到所有的能源都被吸收才会结束;这不仅仅影响灯光的颜色，也影响渲染的品质。我们需要添加光源来模拟这个效果？ Scale of light sources 光源规模 What is the scale of our light sources in relation to our three-dimensional scene? Believe it or not, this factor carries a lot of weight when it comes to the quality of the final render. If any lights feel out of place, it could potentially affect the believability of the final product. 相对于我们的三维场景我们光源的规模怎么样？不管你信不信，这个因素包含许多的权重影响到将来的最终渲染质量。如果任何的灯光感觉放置错误，它将有可能影响最终产生可信的效果。The goal of these questions is to prove to ourselves that the scene were lighting has the potential to exist in real life. Its much harder, if not impossible, to light a scene if we dont know how it could possibly act in the real world.这些问题是为了证明我们的场景照明来自于真实的世界的照明。如果我们不知道真实世界的照明是怎么样的，要照明一个场景，它是非常难的，几乎是不可能的。（如果不知道下雪天是怎么样的，要在3D场景表现雪地场景就几乎是不可能的）。Lets take a look at these questions. 让我们看看这些问题。 What is the weather like? In our case, were not concerned with anything too challenging, weather wise. The goal of this tutorial is to depict our tricycle in an environment that reflects the effects of a sunny, cloudless day. To achieve this, we are going to use lights with blue and yellow hues for simulating the effect the sun and sky will have on our tricycle.天气看起来怎么样? 在我们的案例，我们不需要考虑天气的变化。这个指南的目标只需要模拟我们的三轮车在晴天少云的环境下反射的效果。要实现这个效果，我们将使用黄色调和蓝色调来模拟阳光和天空作用在我们的三轮车的效果。 What are the sources of our light and where are they coming from in relation to our scene? In a real situation, the sun would provide most of the light, so well need a key light that simulates how the sun works. In our case, we can use a Sun lamp. The key to positioning light sources within a three-dimensional scene is to find a compromise between achieving the desired mood of the image and effectively illuminating the object being presented.我们的光源是什么和来自我们的场景什么地方？在真实的世界太阳提供了大多数的光源，所以我们需要一个主光源来模拟太阳是如何工作的。在我们的案例，我们使用太阳灯。关键是3D场景里面的光源要在渲染场景气氛和照明物体之间找到平衡点。 What is the scale of our light sources? The sun is rather large, but because of the nature of the Sun lamp in Blender, we dont have to worry about the scale of the lamp in our three-dimensional scene. Sometimesmore commonly when working with indoor scenes, such as the scene well approach latercertain light sources need to be of certain sizes in relation to our scene, otherwise the final result will feel unnatural.我们的场景灯光规模是什么样的？太阳是相当巨大的，但因为Blender的阳光的特征，我们不需要担心我们3D场景的灯光比例。有时我们更多的工作在室内场景，如我们稍后将要创建的场景-创建光源需要创建相对于场景的尺寸，否则最终的后果将感觉不自然。Although we will be using a realistic approach to materials, textures, and lighting, we are going to present this scene as a product visualization. This means that we wont explicitly show a ground plane, allowing the viewer to focus on the product being presented, in this case, our tricycle. 虽然我们使用真实的材质，纹理和灯光，我们将要表现的是一个产品展示场景。这意味着我们不需要明确显示一个地板，允许将我们的焦点放在产品上，在本案例是我们的三轮车。Planning our light rig 计划灯光布局Knowing that our scene has the potential to really exist somewhere in the real world, we can now plan how we want to set up our lamps within Blender to produce a realistic result.认识到我们的场景是来自于真实世界，我们可以计划在Blender布置灯光来产生一个真实的渲染。The first step in this process is to choose an appropriate light rig. Think about the mood we want to create and the environment our scene containsdo we need harsh lighting with sharp shadows, or maybe something more evenly lit? Once we know what we want, we can choose between any of the light rigs we learned about in Chapter 1, Introduction to Color Theory and Lighting Basics in Blender. Remember, these options include:这个过程的第一步是选择一个合适的灯光布局。考虑我们创建的场景环境气氛包含我们需要刺目的光锐利的阴影或平和的灯光？一旦我们知道我们想要什么，我们可以选择用第一章色彩理论和Blender灯光基础学习的布局装置，这些选项包括： 1-Point light rig 一点布光法 2-Point light rig 二点布光法 3-Point light rig 三点布光法 4-Point light rig 四点布光法Sometimes, well light scenes that require a combination of light rigs. If thats the case, try to imagine how lights would be set up in a real situation to create the effect we want to reproduce.We should also think about what lamps we should use in our rigs. Remember, each lamp type in Blender has its own unique qualities and will simulate some types of real-world light sources better than others will. The types we can choose from, as seen in the previous chapter, are:有时候，我们照明场景需要使用联合的布局法。如果有一个再现真实世界那样的例子，试着想象下怎么设置灯光来实现那样的效果。我们也应该考虑我们的灯光布局使用什么类型的灯光，在Blender每一种类型的灯光都有自己的特点，使用其中的一种灯可能比另外一种灯能够更好的模拟真实世界的灯光。我们可以选择的类型灯光如前面所学的有： Point lamp 点光 Sun lamp 阳光 Spot lamp 聚光灯 Hemi lamp 半球光 Area lamp 面光源For this particular scene, we are going to use a 3-Point light rig. If needed, well add a fourth later. The 3-Point light rig is appropriate for two main reasons:在这些特定的场景，我们将使用3点灯光布局。如果需要，我们添加稍后第四个灯光布局。三点灯光布局比较适当的有两个主要的理由： This is an outdoor scene. In a natural setting, light would be illuminating our object from every angle. The 3-Point lighting rig can simulate this phenomenon, and when properly set up, will effectively illuminate our object without a problem.这是一个户外场景。在一个自然光的设置，灯光照明物体是从单一的角度。三点布光法能够模拟这个现象，当有合适的设置将有效的照明我们的物体。 We are promoting a product, in our case, a tricycle. When working with scenes of this nature, it is a good practice to light objects from multiple angles to best advertise the product or service being advertised.在我们的例子是宣传一个三轮车产品。当在场景使用三点布光法，它能够很好的从多个角度照明物体产生最好的宣传产品或广告效果。In addition, fill and rim lights will help increase the perceived dimensionality of our three-dimensional objects, simulating the effect of light refection and refraction.添加补光和背光将增强3D物体的立体感，模拟灯光的反射和折射效果。Setting up our scene 设置场景Weve conceptually developed our scene and created a light setup that will realistically reflect how our tricycle could possibly be lit in the real world. Now we can open our three-dimensional file and physically begin positioning lamps in Blender.我们对我们的场景和创建一个如何在真实世界创建一个灯光布局来实现三轮车的真实反射效果有了一个概念。现在我们打开我们的3D文件和开始在Blender中按照自然规律布置灯光。Wolfgang Staudt /photos/wolfgangstaudt/640522931/This is where our knowledge of color theory will come in handy. For example, if our scene takes place in a park, we may use blue, yellow, and green hues to reflect the color of light given off by the sun, sky, and grass.这些是我们色彩知识的运用。例如，如果我们的场景是一个公园，我们也许会使用蓝色，黄色，绿色来表示太阳，天空和草地反射的灯光颜色。Theopie /photos/opie/916777666/On the other end of the scale, if our scene takes place in a dark setting, such as a bar, we may choose to use colors like red, brown, green, and/or purple to simulate the colors created by the wood of the bar itself, the colors of the bar stools, or the colors of the neon sign flashing in the window. You may even include a blue light to simulate the flickering street lamp across the street.另一个方面的规模，如果我们的场景是在一个暗黑的场景，如一个酒吧，我们也许选择使用像红，棕，绿或紫色来模拟酒吧本身的颜色，酒吧凳子颜色，或在窗口闪烁的霓虹灯的颜色。你或许甚至包括蓝色的灯来模拟穿过街道闪现的街道灯。When you open your scene for the first time, you should see something similar to the following image. If you dont, make sure you download the right file from the website /lighting-and-rendering/.当你第一次打开场景，应该看到相似的如下所示的图。如果不是，确保在站点/lighting-and-rendering/.正确的下载了文件Setting up a 3-Point light rig 建立一个三点灯光布局法Earlier, we decided we wanted to use a 3-Point light rig. Lets review this quickly. A 3-Point light rig consists of three light sources:我们决定我们想要使用三点灯光布局法。让我们快速的回忆前面所学的，一个三点灯光布局由三个光源组成： Key light 主光 Fill light 补光 Backlight 背光The fill light is placed to the side of the object, typically on the opposite side of the camera that the key light is on. Aimed toward the three-dimensional objects being illuminated, the purpose of the side light is to lighten some of the dark shadows and increase the perceived dimensionality of the three-dimensional object.补光放置在物体的两侧，典型的是在相机和主光对面的一边。朝向三维物体，补光的目的是照亮一些黑暗的阴影增强三维物体的立体感。The backlight, or rim light, is important because its purpose is to create a sharp highlight on the edges of our three-dimensional object, forcing it to pop away from the background. This lamp is placed behind our object, opposite our camera. For best results, we should find a happy medium between the three-dimensional object and our camera to aim this lamp.背光也叫边缘灯光，是很重要的，因为它的目的是在我们的三维物体产生一个锐利的边缘，和背景区分开来。这个灯光放置在我们的后面，我们相机的对面。我们要在三维物体和相机对着这个灯光找到很好的平衡点。The key light is positioned next to the camera, that is, at the same distance from the three-dimensional grid and slightly to either side. In most cases, as in ours, the key light is aimed in the direction of the three-dimensional object, or objects, being lit.主光常常挨着相机，有同样的距离和轻微的在一边。在大多数的例子，如我们的例子，主光是对着三维物体的方向，或组，产生照明。Because the majority of the light that is used to light our tricycle will be coming from the sun, we can start constructing the 3-Point light rig with a sun lamp.因为tricycle的主要照明来自太阳，所以我们可以开始使用一个阳光灯来构成三点灯光布局。1. In Blender, add a Sun lamp by selecting Add | Lamp | Sun. 在Blender 选择信息窗口的add菜单| Lamp | Sun添加一个阳光灯。 Using either the G-hotkey or the Transform Widget, move the lamp so that it is just to the left of the camera. 按G键或N键打开属性值改变移动的权重值移动灯光到相机的左边。 Rotate it using either the R-hotkey or the Rotation Widget, so that its aimed in the direction of the tricycle. 按R键或N键打开属性值改变旋转的权重值，以至它的方向对准tricycle。 Give it a slight downward angle by rotating it along the horizontal axis (the local X axis). This will simulate the sun illuminating the tricycle from above.沿着水平方向轻微的向下旋转一定的角度（局部X轴）。这将模拟tricycle上面的阳光照明。2. If you render it out (Render | Render Image or the F12 key), you should get something similar to the following image:如果你已经渲染完了（Render | Render Image或按F12），你应该可以看到相似的图像：If you are a Macintosh user, you may have to press fn + F12 to render the image properly. This bypasses the default Apple commands preprogrammed into the operating system.如果你是苹果用户，你可能要按fn +