Blender灯光和渲染第五章.doc

Indoor Lighting: Setting Up 室内灯光的建立Now that were familiar with how to light a scene with the characteristics of outdoor lighting, its time to take the next step and look at lighting interior spaces. Many of the techniques we used to light our last scene will transfer to this project quite nicely.现在我们已经熟悉了典型的场景照明，现在看看室内空间。在上个场景我们用来照明的技术都可以非常适当的转到这个项目。However, there are some important differences that were going to have to discuss that are unique to interior lighting. Were going to take a look at:然而,它们有一些很重要的不同之处，我们将讨论这些室内灯光的不同之处。我们将要学习的是： Setting up our scene for use with a complex lighting system使用复杂的灯光系统设置我们的场景 Implementing a more complex lighting system使用更复杂的灯光系统 Setting up lights to reflect artificial lights in our scene, intuitively在我们的场景建立人造的反射灯光。Lets get started!准备开始学习！The first few steps 第一步Before we begin, we need to know what our scene looks like. If you havent already, go to the website (/lighting-and-rendering) and download the file interior.blend from the Interior Lighting download section. This is the file we will be using over the course of this project.在我们开始前，我们需要知道我们的场景是怎么样的。如果你没有场景，到站点/lighting-and-rendering从Interior Lighting下载interior.blend文件。这个文件将被用在我们的课程项目。If you open it, it should look similar to the following image:如果你打开了该场景，应该看到类似如下的图像：Diving inNow that we have the right scene, lets get started. In the last project, the first step we learned was to evaluate our scene. In our case, we are really going to have to carefully consider how were going to set up our lights. Lets take a moment and take a look at that now.现在，我们有正确的场景，让我们开始。在上一个项目，第一步学习了评估我们的场景。在我们的案例，我们必须认真的考虑怎么建立我们的灯光。让我们现在去看看。Enhancing our render using layersWith more complex scenes, Blenders layer system becomes an invaluable tool for lighting. Many times, well find that there are some objects that need unique lighting setups that arent necessarily needed for the entire scene. To set up those unique mini light rigs, we need to link certain lights to specific layers, which we learned how to do in the last project. But we have a problemright now, our scene is all on one layer. This means, we have to decide how we want to break up the objects in our scene so we can light them properly.对于更更复杂的场景，Blender的层变成一个非常重要的工具。许多时候，我们发现一些物体需要独特的灯光系统，但又不需要应用到整个场景。要建立这些“迷你”的灯光系统，我们需要在特定的层创建灯光，在上个项目我们已经学习了这样的做法。但现在我们有一个问题是我们所有的场景都在同一个层。这意味着，我们要怎么打破我们的场景物体让我们可以适当的照明它们。Lets take a quick lookBefore we begin, we need to figure out what kind of mood we want to set. For this scene, were going to want to focus on the wine bottle in the foreground, muting the background a bit using darker lighting and a slight change in focus. This will make the wine bottle the most prominent aspect of our scene. 在我们开始前，我们需要明白我们需要设置的气氛种类。对于我们的这个场景我们想要的是聚焦在我们的葡萄酒瓶，让背景使用暗色的灯光让我们的葡萄酒瓶在场景更突出。Now, lets figure out where our light will primarily be coming from. We have two physical sets of light sources in our scenethe hanging lamps on the right and the embedded ceiling lamps on the left. We can use Spot lamps to simulate the hanging lamps on the right, and for the others, we can use Area lamps. Note that these Blender lamps arent visible in the Blender file; in fact, they dont even exist yet. We are going to add them together later in the chapter. 现在，让我们看看我们场景的灯光来自哪里。在我们的场景设置有两组光源在右边的挂灯和左边的天花灯。我们使用聚光灯（Spot）来模拟我们右边的挂灯，对于其它的灯光，我们使用区域（Area）灯光。注意这些Blender灯光在这个Blender文件是不可见的；甚至它们还没有存在这个场景。我们将在本章的后面添加它们。Adding these lamps will light a good majority of our scene, but we still need to light the wine bottle in a way that makes it stand out from the rest of the scene. Because this is the focus of our scene, were going to use a completely separate light to light it. In order for us to separate these light rigs properly, were going to need to set up our scene in layers. 添加这些灯光能够很好的照明我们的场景，但我们还需要照明葡萄酒瓶，确保它从场景中突出来。因为它是我们场景的焦点，我们将完全使用一个独立的灯光来照明它。为了适当的分离这些灯光系统，我们将需要建立我们的场景层。Organizing our layers 组织层In the real world, objects we see are affected by all available sources of light. In computer graphics, though, we have complete control over how light affects our scene, and as a result, we have the artistic liberty to create effects with light that may not necessarily occur in a naturally-lit scenario for the sake of visual appeal. In Blender, we can separate our light sources using three-dimensional layers, which behave in the same way as layers in Adobe Photoshop or the GIMP. By default, Blender assigns every new object we create to the first layer, but we can move these objects around to fit the needs of our scene. 在真实的世界，物体是由所有的光源的影响。在电脑图形领域，虽然，我们可以完全控制灯光是怎么影响我们的场景，结果是，我们可以创建许多在我们自然界不会发生的艺术效果。在Blender,我们可以像Adobe Photoshop或GIMP那样使用层单独分离我们的光源，Blender指定新的物体创建在第一层，但我们可以移动它们到其它的层。Deciding which layers to use solely depends on the preferences of the user and the needs of the scene. As long as the layers are used in a way that produces the desired result in the render, there is no wrong way to use them. Lets take a look at how we can use layers in our own scene!使用哪一个层取决于用户的喜好和场景的需要。既然层是以这样的一种方式来实现想要的渲染结果，这是没有错误的使用方法。让我们看看怎么在我们自己的场景使用层！We know we need to light our wine bottle separately. This means that we need to have, at the very least, the wine bottle and the table its on, placed on a layer of their own. For logics sake, were going to leave these two on the first layer to start. Because the wine bottle is the focus of the scene, it makes sense to have it on the primary layer. Because were not sure whether or not were going to need to break up our scene further, lets place everything else in our scene on the layer directly below the first layer on the Move to Layer dialog box. Thats probably confusing to take in all at once, so heres an image to help you. 我们知道我们需要单独的照明我们的葡萄酒瓶。这意味着我们需要，至少需要葡萄酒瓶和桌子在一个单独的层，所以首先我们需要的是让它们从第一层分离。因为葡萄酒瓶是场景的焦点，它制造场景在在最原始的层。因为我们不确定我们将来是否或不需要分离我们的场景，我们在Move to Layer对话框的第一个层创建我们所有的物体。这全部同时或许是很混乱的。所以这里有一个图像可以帮助你。To do this, follow these steps: 要做这些，跟随以下的这些步骤：1. Select everything in our scene, except for the wine bottle and the table its on. The easiest way to do this is to select everything in our scene, with the exception of the camera, and then deselect the wine bottle and table. 选择场景的所有东西，除了葡萄酒瓶和它所在的桌子。最简单的方法是全选所有的物体，然后取消选择葡萄酒瓶和它所在的桌子。2. Press the M-hotkey to bring up the Move to Layer dialog box. 按M键弹出Move to Layer对话框。3. Select the layer button directly below the current layer (the first layer).选择想要的层。This moves everything selected to the designated layer. 这将移动所有选择的物体都指定的层。Lets assume for a moment that were going to use a 3-Point light rig to light our wine bottle similar to the light rig we used for the tricycle in our last project. This means that were going to want our key light to light both the wine bottle and the table. We need this light to affect the table so we can render any shadows cast by the wine bottle. 假定我们使用类似我们上章节所使用的三点照明系统照明我们的葡萄酒瓶。这意味着我们需要主光照明我们的葡萄酒瓶和桌子。我们需要照明桌子效果让我们能够渲染任何的葡萄酒瓶产生的阴影。The side light and rim light, on the other hand, only need to affect the wine bottle itself, not the table. This means were going to have to move the table once more, this time to layer two. Following the same steps we used to move our objects the first time, select the table and move it to the second layer. The second layer is the layer button directly to the right of the first layer button.补光和边缘光，在另一方面，仅仅需要影响葡萄酒瓶本身，不需要影响桌子。这意味着我们将要再次移动桌子，这次移动到层2.跟随着下面和第一次同样的步骤，选择桌子物体并移动到第二层。第二层在第一层按钮的右边。Lets take a moment and quickly review what weve done. As of now, we should have: 让我们看看我们应该怎么样做： Moved everything in our scene, with the exception of the wine bottle, the table underneath the wine bottle, and the camera to the layer directly below the first layer button in the Move to Layer dialog box 移动所有场景的物体。除了葡萄酒瓶，桌子，和相机到Move to Layer dialog到对话框的第一层。 Moved the table once more from layer one to layer two 移动桌子物体到第二层Turning theory into practice 理论转为实践We have a vision for our scene and we know how were going to implement that vision. Now, all thats left to do is to do it. Were going to break this down into smaller stepsthis lighting system is going to become fairly complicated fast, and the last thing we want is to get confused and all turned around. Lets break down the rest of the lighting section of this project into the following steps: 我们的场景有一个版本并我们知道如何去实现这个版本。现在1. Set up the general rig. This includes lamps for the hanging light sources and the ceiling lights. Were not going to worry about light color at this point. With a light rig this complex, were going to want to make sure first and foremost that the light intensity is balanced well before we start worrying about the details. 建立普通的系统。这包括悬挂的灯光和天花灯。现在我们不需要担心灯光颜色。对于这个复杂的灯光系统，在我们开始考虑细节前，首先考虑的是灯光强度。2. Set up the 3-Point rig for the wine bottle and table. 为葡萄酒瓶和桌子建立三点灯光系统。3. Set the lamp colors and set the ambient lighting settings, if applicable. 设立灯光的颜色并设置环境光，（ambient lighting）如果有。4. Tweak until satisfied. 细微调整直到满意。Setting up the general rig 建立一般的灯光系统This step is by far the most straightforward step for this project. We are simply going to place lamps directly on top of the already existing three-dimensional models in our scene. 对于这个项目这个是最普通的系统。我们直接放置到我们场景的三维模型的顶部。Adding Spot lamps 添加聚光灯To start with, lets set up the lights for the hanging lights on the right side of our composition. Were simply going to create, position, and edit one light, then duplicate it to fit the rest of the lights. 让我们开始为我们的作品右边的悬挂灯建立光源。我们只需要简单的创建第一个光源，然后复制到其它的悬挂灯。1. Change into the Top view and make sure youre in wireframe mode by pressing the Z-hotkey. 切换到Top视图并按Z键确保为线框模式。2. Add a Spot lamp by selecting Add | Lamp | Spot. 通过选择Add | Lamp | Spot添加一个聚光灯。3. Using the G-hotkey, position it so its directly in the middle of the lampshade of the hanging light closest to the camera. Refer to the following image for help:使用G键，放置它到悬挂灯的中间。参考如下图像：4. Change into either the front or right view and adjust the lamp so that its positioned at the top of the shade, right below the support, as shown in the following screenshot:切换到前视图或右视图校正让它到灯的中心，如下图所示：Before we continue, make sure that this lamp is on the same layer as the hanging lamps are. This would be the layer found directly below the first layer in the Move to Layer dialog box. If its not already on the right layer, move it using the M-hotkey. 在继续下一步前，确保这个灯光和悬挂灯模型在同一个层。这个层在Move to Layer对话框的第一层的下面。如果不是在右边的层，可以使用M键移动到那。Now we need to adjust some lamp settings to better fit our light source. The first thing we need to change is the cone angle of our Spot lamp. Take a look at any real-life lamps that have shades similar to this onethe light follows the shape of the lampshade. This effect is most noticeable when a lamp is placed next to a flat surface, such as a wall.现在我们需要调整一些灯光设置更好的适合我们的光源。首先需要的是改变我们的聚光灯的圆锥（cone angle）角度。看看真实的灯光的遮挡是相似这个的灯光沿着灯光模型遮挡的外形。这个效果当灯光在一个平的表面附近特别明显，如一个墙面。To change this setting in Blender, make sure our lamp is selected and go to the Light menu.要在Blender改变这些设置，确保我们的灯光被选项并到灯光（Light）菜单。Under the Spot Shape settings, theres a parameter called Size. This controls the angle of the cone, which is set to 45 degrees, by default. Adjust this setting until the edges of the cone run parallel with the edges of the lampshade. It should look similar to the following image:在Spot Shape下，有一个叫Size的参数。这是一个设置圆锥角度的参数，默认是45度。调整圆锥角度直到到灯罩的边缘。看起来类似以下图像：The angle of the cone in the image above is set to 102 degrees, but it may vary slightly, depending on where exactly the lamp is placed.上面的图像的圆锥角度大约是102度，但它很精确的对于灯光。The next step is to change the Blend settingthis setting tells Blender how soft or hard to render the edges of the light on a surface. Our goal is to create a nice, soft edge. For now, set the value at 0.4. This should create a nice enough effect for what were looking for. We also want to change the Energy setting to 0.7. Remember, earlier we decided to incorporate a darker background to make our wine bottle in the foreground pop forward.下一步是改变Blend设置这个设置告诉Blender在一个表面光源的边缘有多硬或多软。我们的目标是创建一个很好的软边缘。现在，设置值为0.4.这足够创建一个很好的效果。我们也改变Energy值为0.7。记得前面我们决定我们需要一个暗暗的背景来突出我们的葡萄酒瓶。The final step is to adjust the Shadow settings. By default, Blender renders ray-traced shadows with Spot lamps, but we want to change this to buffer shadows. Because the area of our scene that will be lit by this lamp will be in the background, we dont have to worry about getting high-quality results, so we can get away with the buffer shadow algorithm. This will also cut down on our render time, because Blender wont have to make all of the mathematically meticulous calculations that come with the ray-tracing algorithm. Under the Sample Buffers setting, perform the following: 最后一步是调整阴影（Shadow）设置。Blender默认的是聚光灯的光线追踪（ray-traced）阴影，但我们想要改变为buffer阴影。我们将通过这灯照明我们场景的背景区域，我们不担心是否有高质量的结果，所以我们可以使用buffer阴影来计算。这也将节省我们的渲染时间，因为Blender 不用对所有的物体都使用光线追踪（ray-traced）进行精确的计算。在Sample Buffers设置下，完成下列操作：1. Set the number of sample buffers to 4. 设置采样缓存（sample buffers）数量为4.2. Set the Size to 1024. 设置Size 为1024。3. Set the Samples to 5. 设置Samples为5.The last step is to select the This Layer Only option under the Shadow settings. This step is the keyif we dont choose this step, our lamp wont be linked to the layer. Although that isnt a huge problem right now, it will be if we dont set it up right with our 3-Point light rig, later in this chapter. 最后一步是勾选Shadow设置下的This Layer Only选项。这是很关键的如果我们不勾选它，我们的灯光将不会连接到层。虽然现在这不是很大的问题，如果我们不在稍后的这章建立三点灯光系统的话。Now that were finished customizing our first light, we can duplicate it to fit the remaining hanging light fixtures. To do so, follow these steps: 现在我们完成了第一个定制的灯光，我们可以复制给其它的悬挂灯。要这样做，跟随下列步骤：1. Select the Spot lamp. 现在聚光灯。2. Duplicate it by pressing the Shift + D-hotkey and transforming it along the x-axis until it lines up with the next lamp object. Your scene, from the front, should now look similar to the following screenshot: 按住Shift + D键并沿着X轴移动直到它对齐到下一个灯光物体。你的场景的前视图看起来应该是这样的：3. Repeat steps 1 and 2 until the entire row of hanging lamps is set up. Once thats done, we can move on to the other set of lights! 重复步骤1和步骤2直到建立所有的悬挂灯光。完成后，我们将去设置其它的灯光!Lets take a look at how our scene looks so far. With only the Spot lamps lighting the scene, we get an effect similar to the following render: 让我们看看我们的场景现在是怎么样的。对于只有聚光灯的场景，我们得到以下的渲染：Before we create our next lamp, we need to move the lampshades to another layer. With the lampshade selected (named lamp_shade), move it using the M-hotkey to the layer next to the layer its currently on. 在我们开始创建下一个灯光前，我们需要移动我们的灯罩到另外的层。使用lampshade选择(名字叫lamp_shade),使用M键移动到当前层的下一层。With the new layer selected, add a new Point lamp. This lamp will light the interior of our lampshade, giving it the impression that the light bulb is really affecting it. Move the new lamp using the G-hotkey so its in the same place as our light bulb object. Also, change the color of this lamp to match the yellow hue Spot lamps we created earlier. 在新的选择层，添加一个点光源。这个灯光将照明我们的灯光内部，给它一个灯泡的效果。使用G键移动新创建的灯光让它和灯泡物体在同一个地方。改变这个灯光的颜色以匹配我们前面创建的聚光灯。Before we render, we have to do three things. The first is link the lamp to the layer. 在我们渲染前，我们有三件事情要做，首先是链接灯光到层。To do this: 如下：1. Without the lamp selected, select the This Layer Only option under the Lamp settings. 选择灯光物体，勾选Lamp设置下的This Layer Only选选项。2. Next, turn on shadows by selecting Ray Shadow underneath the Shadow settings. The default values are fine.接下来通过点击Shadow下的Ray Shadow按钮打开。默认的设置是已经很好。3. Like we did with the Spot lamp, duplicate our new lamp and move it so it fits under every hanging lamp.像我们的聚光灯（Spot），复制我们新的灯光并移动它们到每个悬挂灯的下面。Now lets render out our image!现在让我们渲染我们的图像！Its a good start! Lets add some more lamps!这是一个很好的开始！让我们添加更多的灯光！Setting up Area lamps 建立区域灯光The second set of lights can be approached in the same way the first set was. The biggest difference between the two is the type of lamp used. Because the lights above the booths are held in rectangular casings, the best lamp we can use to simulate this is an Area lamp. This can be done by performing the following steps: 第二组灯光可以使用和第一组相同的设置方法。最大的差别是两种灯光类型的用途。因为要照亮的小房间上面是长方形，所以最好的使用区域灯（Area lamp）来模拟。可以通过如下步骤完成：1. Change into the Top view. 切换到顶视图。2. Add an Area lamp by selecting Add | Lamp | Area.通过Add | Lamp | Area菜单添加一个区域灯。3. Position it using the G-hotkey so its placed directly above the booth farthest right. Also be sure to change into the Front or Right view to make sure the lamp is facing downward and positioned as close to the ceiling as possible. Refer to the following image for help:使用G键移动到小房间的最右边。切换到前视图或右视图确保灯光是朝下并尽可能接近天花。参考以下图像：Although there isnt a table at the far right booth, the viewer assumes that our scene expands beyond the frame of our image. This means that we need to create the illusion that our scene continues beyond our render by adding this lamp.虽然这没有一张桌子在小房间的右边，观察假定我们的场景越出我们的图像范围。这意味着我们需要通过添加这个灯光来创建我们的场景继续在我们的渲染范围外的假象。As with our Spot lamp, were going to duplicate our Area lamp so we can preserve our settingsthis way, we dont need to repeatedly set the same settings. Before we do this, though, make sure its on the same layer as our Spot lamps by selecting the lamp and moving it to the proper layer using the M-hotkey. Now to start, we need to change the shape of the lamp to better reflect the shape of the actual light model. With the Area lamp selected, go to the Lights menu and take a look at the Area Shape settings. 像我们的聚光灯那样，我们将复制我们的区域灯并可以保持相同的设置，我们不需要担心同样的设置。在我们开始前，我们可以和我们的聚光灯的移动层的方法按M键移动区域灯到合适的层。开始，我们需要改变灯光的形状适合实际。选择区域灯光，到Lights菜单并看看Area Shape设置。By default, Blender creates a square Area lamp, but were going to want a rectangular one. To change this: 默认的，Blender创建一个正方形的灯，但我们想要一个矩形的灯光。