You might find yourself wondering what possible uses there could be for having objects be members of multiple collections. The simple (but not easy) explanation is scene organization. This is especially true as your scenes become more and more complex. You may have a scene full of foliage. Each tree, flower, and shrub is part of a corresponding collection, each named “trees”, “flowers”, and “shrubs”. Now say you’re doing a little physics simulation on that scene and you only want the tallest trees and shrubs to be affected by that wind force. You wouldn’t want to pull your trees and shrubs from their collections to a collection called “physics”. It would be much better if those trees and shrubs could be members of both collections.
If you choose the Object ⇒ Collection menu, you have a number of options:
Move to Collection (M): This menu item invokes the operator used in the preceding example. Whatever objects you have selected get moved to another collection, either pre-existing or new.
Link to Collection (Shift+M): This operator is similar to moving your selection to a collection, but it does so without being removed from any collections your selected objects are already members of. This is how you get an object to be part of multiple collections.
Create New Collection (Ctrl+G): This option is always available and creates a new collection, adding your selected objects to it. Be warned, though. As of this writing, when you add a new collection with this menu item, it doesn’t show up in the Outliner, even though you can plainly see it in the Object tab of the Properties editor. For the time being, I’d suggest that you avoid using this menu item.
Remove from Collection (Ctrl+Alt+G): This option is always available, and choosing it removes the selected objects from any collections they may be a member of. Removing all objects from all collections doesn’t delete those collections while your Blender session is still active.
Remove from All Unlinked Collections (Shift+Ctrl+Alt+G): This is a quick shortcut to remove the selected objects from all the collections they may be a member of.
Add Selected to Active Collection (Shift+Ctrl+G): To use this feature, you need to pay attention to which object is your active object (hint: it’s the most recent object you’ve selected). Then any objects you have selected become members of all the collections your active object is a member of.
Remove Selected from Active Collection (Shift+Alt+G): Choose this option, and all your selected objects (including the active object) are removed from any collections in the active object.
Selecting with parents and collections
When you’re using parenting and collections, you gain the ability to rapidly select your objects according to their groupings. Choose Select ⇒ Select Grouped or press Shift+G, and you see a menu with a variety of options:
Children: If you have a parent object selected, choosing this option adds all that object’s children to the list of selected objects.
Immediate Children: Similar to selecting all children, except this option traverses down the hierarchy by one step only. Children of children are not added to the selection.
Parent: If the object you’ve selected has a parent object, that parent is added to the selection.
Siblings: This option is useful for selecting all the children of a single parent. It does not select the parent object, nor does it select any children that these sibling objects may have.
Type: This option is useful for making very broad selections. Use Type when you want to select all lights or all meshes or armatures in a scene. This option bases its selection on the type of object you currently have as your active object.
Collection: Use this option to select objects that live in the same collections. If an object is in multiple collections, any objects that share any collection with your selected object are added to the selection.
Hook: If you’ve added hooks, which are objects that control selected vertices or control points in an object, this option selects them. You can find more information on hooks in Chapter 12.
Pass: Similar to layers, objects may have a Pass Index value that is useful for compositing and post-production work in Blender. Choosing this option selects any objects that share the active object’s Pass Index value. You can find more information on passes and the Pass Index in Chapter 18.
Color: This option allows you to select objects that have the same color, regardless of whether or not they link to the same material datablock.
Keying Set: Keying sets (covered more in Chapter 13) are used for organizing a group of objects and properties for animation. They’re properties that all have keyframes set at the same time. This option selects all objects that share the current object’s keying set.
Light Type: This option is similar to the Type option, though it’s specific to lights. If you currently have a light selected, choosing this option also selects any lights of the same type (such as Spot, Point, Area, and so on).
Saving, opening, and appending
Quite possibly the most important feature in any piece of software is the ability to save and open files. Having quick access to saving and opening files was especially useful for early versions of Blender, which lacked any sort of undo function. Blender users learned very quickly to save early, save often, and save multiple versions of their project files. One beneficial side effect of this history is that Blender reads and writes its files very quickly, even for complex scenes, so you very rarely ever have to wait more than a second or two to get to work or save your project.
To save to a new file, choose File ⇒ Save As from the main header or use the Shift+Ctrl+S hotkey combination. One strange thing that you may notice is that Blender doesn’t open the familiar system save dialog that Windows, Mac, or Linux uses. This is for a couple reasons. Because Blender uses its own File Browser interface, you can be guaranteed that no matter what kind of computer you use, Blender always looks and behaves the same on each platform. And as another point, the Blender File Browser has some neat Blender-specific features that aren’t available in the default OS save dialogs.
Take a look at the File Browser shown in Figure 4-14. The header for this editor features an assortment of buttons for navigating your hard drive’s directory structure and filtering the files shown. If you’ve used the file browser that comes with your operating system, most of these buttons should be familiar to you. The options in the side region on the left of the File Browser are there to give you shortcuts to various locations on your computer’s hard drive.
The largest portion of the File Browser is devoted to actually showing files and folders. The topmost text field in this region is the current path on your hard drive to the folder/directory you’re currently viewing. At the bottom of the File Browser is the text field for the actual name of your file. In this field, type your project’s name. Pressing Enter or clicking the Save As button at the bottom right corner saves the file for you. Between the header and Current File text field is a list of the files in the current folder. Figure 4-14 shows the Blender File Browser