When editing, we often want to keep the present version of our edit intact, while moving forward with more work, being able to get back to it in at the current state, easily. In Final Cut Pro X there are a few ways to do this. The first thing to remember is that everything in FCP X is a 'Timeline'. Even a video clip or an audio clip are just Timeline containers for the original media. You can see this by right-clicking a clip in the Browser, and select 'Open In Timeline'. You'll see the clip Timeline container opened, and the contents revealed. You'll see a video and/or an audio clip inside of it. So, on to how we version these things.
In the Browser pane we can view all of the media assets in our Libraries and Events. Each one of these, be they a photo, graphic, video with audio, audio only, all of them are actually virtual containers for the original, physical media file. These containers are referred to in FCPX as Timelines. As stated above, you can right-click any of them in the Browser, choose 'Open In Timeline' and see it inside of its own Timeline virtual container.
We can alter these originals, or 'Master Clips' so that every time we drop them into another Timeline, such as a Project or Compound or Multicam, the alterations are there pretty permanently. We can also open any of these into their own Timelines inside of other Timelines, also, to further alter them. Just like in the Browser, inside of the Timeline pane, right-click and choose 'Open In Timeline'. You can make changes there. BUT, those changes will reflect ONLY inside of the Timeline it is in. Only that specific copy of the Master clip will be effected. Once dropped into a Timeline, a Browser media asset becomes independent. Compounds and Multicams are NOT like this, as we will discuss later.
If I want to alter a Master clip but retain a copy of that original, I will use the Duplicate command. With the Master clip selected in the Browser pane, I can go to the Edit menu and select Duplicate Clip, or I can simply use the Command-D keyboard shortcut. This makes a duplicate copy, a new Master file, with the word 'copy' appended to the original clips name. I can now open this clip in its own Timeline and alter it without effecting the original Master clip.
The advantage to this is that all of these copies refer back to the original media file on the hard drive. That physical file is NOT duplicated, it is NOT altered in any way. Only the virtual copies you are making inside of FCP X are being copied and altered. Physically this is only the data being written to the Library/Event/Project databases. That said, remember two things. First, duplicating clips and other media in the Browser pane, you are creating a new, independent Master clip. Second, duplicating clips in the Timeline pane, you are creating a new Timeline copy that is not associated to the Master in the Browser at all. Third opening a Timeline pane copy into its own Timeline only effects that individual copy of that clip.
I know, on paper this seems complex, but it really isn't. Play with this inside of FCP X for a few minutes, it will become very clear, logical, and second nature.
The first method of versioning the Timeline type we call a Project, is to duplicate it. There are several ways to do this. You can select the Project in the Browser pane, right-click and chose 'Duplicate'. Or with it selected there, or with it open and active in the Timeline pane, select Duplicate in the Edit menu. Or use the keyboard shortcut Command-D. This will create an exact duplicate of your Project, appending a number (1, 2, 3, etc.) to the end of the name to help you track which is which. The 'Content Created' column of the Browser can help track when each was created, also.
The advantage/disadvantage to this method are Compound Clips and Multicam Clips. These both refer to a 'Parent Clip' in the Browser. That Parent Clip is what all copies in all Timelines refer back to. If you make a change to the Parent, or to any of the Timeline copies (child clip), the ALL reflect the exact same change across the board.
To avoid the Parent Clip issue mentioned in the previous section, we can make a Project Snapshot. There are several ways to do this, also.
You can select the Project in the Browser pane, right-click and chose 'Duplicate As Project Snapshot'. Or with it selected there, or with it open and active in the Timeline pane, select Duplicate As Project Snapshot in the Edit menu. Or use the keyboard shortcut Shift-Command-D. This will create an exact duplicate of your Project, appending the date and time you created it, to the end of the name.
The advantage/disadvantage to this method is that all Compound Clips and Multicam Clips are frozen, and no longer refer to the Parent Clip. They become independent. So making a change in any other copy, or in the Parent, will NOT change anything to it in this specific Project Snapshot.
Compound clips can be very handy things to do isolated edits and compositing inside of. On occasion we want to version these, just like Projects. The quickest way to do this is to select the Compound Clip in the Browser pane and use the Command-D keyboard shortcut. You can also find the Duplicate command in the Edit menu. This will make a duplicate of the Compound Clip with the word 'copy' appended to the original name.
The advantage/disadvantage to this method is that you are actually creating a new Parent clip. Thus, these two versions of the original Compound Clip have nothing to do with each other. Making a change in one will NOT make a change in the other. But each will effect any copies made from each specifically in any other Timelines they were dropped in to.
You can also duplicate a Compound Clip via the 'Reference New Parent Clip' command in the Clip menu. This only works when you have a Compound Clip selected in the Timeline pane. Command-D works in both the Browser and Timeline panes.
Using the Copy & Paste method inside of the Timeline pane will only create a new copy of the Parent clip, not a new Parent.
I hope this article clarifies the various ways to use duplication, snapshots, and copy/paste to version Master media, Projects and Compound Clips in FCP X. Plus I hope it clarifies the advantages and disadvantages of each. There are appropriate times to use each, and because each post-production job can be unique, only you the editor can decide when to use which method. No matter which technique you choose, Final Cut Pro X offers enough variety to cover just about any versioning need.