There are two ways to bring files and geometry into a Maya scene: importing and referencing. When you import a file into Maya, you're merging a copy of the file's contents into the current scene. If you make changes to the original file, they aren't reflected in that scene, and vice versa.
Alternately, you can use the same file in multiple scenes by referencing it (Figure 1.45). A referenced file isn't copied into a scene; instead, it's loaded into a scene every time you open it. Referencing a file allows you to edit the original file and have those revisions reflected in all the scene files that use the reference. For instance, you can create a character in one file and then reference it into different files for each camera shot in your animation. If you later want to make changes to the character, you can open the original character file, make the changes, and then save the file. When you open your animation files, your character will be updated (Figure 1.46).
Figure 1.45. Referencing a file into multiple scenes allows the original scene file to be edited; the reference files inherit the changes.
Figure 1.46. Changes made to a referenced file are automatically included in each scene in which the referenced file is used.
In addition to importing and referencing, you can also export objects out of a scene.
When you're editing referenced files, the names of nodes and objects become extremely important. If the names change in the original file, then any scene that refers to them will no longer be able to find those objects.
You can temporarily unload referenced files in the Reference Editor to make complex scenes more manageable (Figure 1.47).
Figure 1.47. Unloading references can greatly improve real-time performance while animating.
To import a file:
Choose File > Import (Figure 1.48).
Figure 1.48. Importing a file into another scene combines the imported file with the open file.
The Import dialog box opens.
Navigate to the folder where the file you want to import is located.
Click the file you wish to import, and then click Import.
The file is imported into the scene.
To reference a file:
Choose File > Create Reference (Figure 1.49).
Figure 1.49. Select File > Create Reference to reference a file into an existing scene.
The Reference dialog box opens.
Navigate to the folder where the file you want to reference is located.
Click the file you want to reference, and then click Reference.
The file is referenced into the scene.
To export selected objects:
Select the objects you want to export.
Choose File > Export Selection (Figure 1.50).
Figure 1.50. This apple has been selected to be exported separately from the rest of the scene.
The Export window opens.
Navigate to the folder where you want to place the exported file, and enter a filename.
The selected objects are exported.