Updated for Blender Version: 3.1
Get to the Point
Link/Append
- File > Link/Append
- Navigate to .blend file to import
- Select the element to import (ie. Object > Suzanne)
- Click Link/Append From Library
Import/Export
- File > Import/Export
- Select file type
- Choose file to import/loction to export to (whichever is applicable)
- Click Import/Export in upper right
Importing and Exporting
Importing and exporting in Blender is very straightforward. Under the File dropdown, there are menu options for Import and Export, which have fly-out menus showing a variety of 3D file types.
Appending
Appending applies specifically to Blender files. Use Append as a copy-paste function from one .blend file to another. Click File > Append to bring up your system files, or use the hotkey Shift+F1. Navigate to the .blend file from which you want to copy an object, for example. Double-clicking on the .blend file will display all the elements saved in that project. Navigate to the /Object folder, select the object you wish to copy (this is why naming conventions are important), and then click Append from Library in the top right corner. This will copy and paste that object from the original .blend file to the new .blend file. These steps can be repeated for anything within the original .blend file: lamps, textures, world settings, etc.
Linking
Linking is similar to appending in that it is also used specifically for Blender files, though it is a bit more complicated. A linked object means that the object is still tied to the original, even when it is copied to a new scene. This is useful for when multiple people are working on the same project. The original file remains unchanged, but can be copied to a new project. The steps are the same as appending: File > Link or Ctrl+Alt+O, find the .blend file to link from, then select the element you wish to link, and click Link from Library in the top right.
Generally, appending should do the trick if you want to copy an object (or other Blender element) from one .blend file to another.