Blender For Dummies. Jason van Gumster

is /home/user/Documents/. Now say that you have a folder named textures in the same folder as your project.blend file, and in that folder is an image named sandpaper.png. The absolute path to that image is /home/user/Documents/textures/, while its relative path (relative to project.blend) is //textures.

       System

Whereas the Interface options dictate how you interact with Blender, the options in the System section, shown in Figure 2-9, tend to dictate more how Blender interacts with you. Many options here are geared toward optimizing for performance, and generally the defaults work well.

       Figure 2-9: The System options in User Preferences.

      Some of the more interesting options follow:

      ✔ Compute Device: If you're using Cycles as your renderer, the settings here are pretty important. If your computer has a sufficiently powerful graphics processing unit (GPU) – usually this is your computer's video card – Cycles can take advantage of that additional processing power, dramatically reducing the amount of time required for rendering. Depending on your GPU type, you'll want to set this to either

      ● CUDA (for NVIDIA GPUs)

      ● OpenCL (for AMD/ATI GPUs)

      You can then choose the specific GPU from the drop-down menu.

      If you don't have the kind of GPU that Cycles can take advantage of, there's no need to worry. The Compute Device defaults to None and Cycles will just use your CPU. You can read more about Cycles in Chapter 14.

       As of this writing, the OpenCL option for Compute Device doesn't work particularly well on AMD GPUs. There's hope that it may be fixed and working in the future, but that depends on AMD changing their drivers. In the meantime, if you have an AMD video card, you're probably best keeping the Compute Device option set to None.

      ✔ OpenGL: If Blender is working sluggishly or if the interface looks really odd (noise, strange tears, repeating patterns), these settings are the first place to look to see whether you can get Blender working nicely. In particular, you may want to try enabling vertex buffer objects (VBOs). With VBOs enabled, Blender's interface should be snappier on more modern video cards. However, on older hardware, VBOs may cause Blender's screen to behave strangely.

      ✔ Window Draw Method: This drop-down menu is another fine place to look if Blender is displaying bizarrely on you. The default setting of Automatic should give you the best performance on your computer. However, if you're on an older machine, try seeing whether the Overlap or Full methods work better.

      ✔ Region Overlap: If you enable this check box and you have a sufficiently modern video card, the regions in the 3D View (the Properties region and the Tool Shelf) will be semi-transparent, allowing your 3D scene to show through them. Not only is this attractive, but it helps keep as much of your 3D scene visible as possible.

      ✔ Solid OpenGL Lights: With these settings, you can adjust the standard lighting used in your 3D View. Some Blender users set these colors to drastically different settings so that they can have a good sense of each side of their model and more easily see some of the contours. You have the ability to enable up to three lights. On each one, you can adjust the direction of the light by adjusting the X, Y, and Z direction values. You can adjust either of the two colors for the light (main color and highlight or specularity color, respectively) by left-clicking them and using the color picker that pops up.

      ✔ Color Picker Type: Speaking of color pickers, Blender gives you the option of a variety of ways to choose colors while working. The default is a circular hue, saturation, value (HSV) color picker. It's generally faster to use for choosing colors when painting. However, everyone has different tastes in what color pickers they prefer to use, and some color pickers are better than others for specific purposes. For that reason, a drop-down menu contains a selection of different color pickers that you can use in Blender. Play with the color pickers on the Solid OpenGL Lights and see which one suits you the best.

Using custom event maps

      A primary inspiration for the deep structural changes introduced in Blender's code for the 2.5 series was to refactor Blender's event system. An event system is required for a complex program to interact with you and me, the users. Each time you press a button or move your mouse, it registers with the program as an event. The program then handles the event by performing an action of some sort. As an example, moving your mouse registers as an event, which then triggers your computer to perform the action of updating the location of the mouse cursor on your monitor.

      Blender provides you the ability to customize the event system to suit your needs, mapping events to a wide variety of possible Blender operations. Don't like using a particular hotkey in Blender's default configuration? You're free to change it. And that's just the start!

      If you refer to Figure 2-5, you should notice that the entire right side of the editor is devoted to modifying how events are handled within Blender. This list of events is particularly daunting to look at, and you can easily get lost among all of those expanding and collapsing categories of events. Fortunately, you can modify how events are handled in a much easier way, and you don't even have use the User Preferences editor if you don't want to. Instead, you can use the following steps:

      1. Find the operation you want to bind in Blender's menu system.

      Say that you want to change the hotkey for opening a new project from Ctrl+N (the current hotkey) to Ctrl+X, the hotkey used in previous versions of Blender. You can find this operation by going to the Info editor's header and choosing File⇒New. Go to that menu item, but don't click it yet. Just hover your mouse cursor over it and proceed to the next step.

      2. Right-click the menu item for the operation you want to add or change hotkeys and choose Change Shortcut from the menu that appears.

      In this example, go to File⇒New, right-click it, and choose Change Shortcut. Blender prompts you for a new hotkey.

      3. When prompted, use the new hotkey that you want to assign to the operation.

      In this case, you press Ctrl+X.

      Congratulations! Your new hotkey is assigned!

Figure 2-10 shows this process in action.

       Figure 2-10: Customizing a hotkey sequence directly from Blender's menus.

       As of this writing, Blender doesn’t warn you if you attempt to assign a hotkey that has already been bound to another operation. Blender simply double-binds the hotkey, favoring default behaviors over custom ones. Blender's interface will still say your custom hotkey is assigned to the desired action, but it just won't work as expected. Currently, the only way to get around this problem is to make sure that your desired hotkey isn't already assigned.

      Of course, for ultimate control, the Input section of User Preferences is really the way to go. As daunting as this section may appear, it's actually pretty easy to use. The most effective way to make use of the event editor is to use the search feature, a text field with a magnifying glass icon in the upper right corner of the Input section:

      1. In the search filter field, type all or part of the operation you want to customize and press Enter.

      The