Single frame background

[artie]

I notice from the CS5 lessons that the background image, the stylised fairground, is rendered out multiple times even though it doesn't appear to change when the moving character is placed on top.
Is there a way to use just one single background frame without having to duplicate it hundreds of times.
This may sound basic but I've only just started rendering out animations and obviously want the most efficient workflow.
thanks.

[Xandros]

There are a few ways to make a single frame into a permanent background.

The easiest way is to right click on the footage and go up to "time" --> "Freeze frame". This should generate a key that will allow you to stretch the single frame infinitely in any direction.

However, certain types of "footage" will not allow you to use a time freeze on them. For example, say you create a new solid and apply something like cc particle world to it. You might get a cool effect and want to to use that as the background, but it won't let you freeze it. The simple solution is to pre-compose that layer (Layer ----> pre-compose). You will then be able to freeze frame it.

Another way to make a single frame a permanent background is to use time remapping. If you again right click on the footage and this time go to "time ----> enable time remapping", this will allow you to set key frames along footage and change how long it takes for the video to get to those points. Basically, you would set a key frame, duplicate it and then slide it forward along the timeline however long you want that frame to last. This is telling after effects that it should keep the same data for that period of time before moving on. You may need to use the pre-compose process for this as well if it won't let you enable time remapping right away.

Another way to create a background out of a frame would be to solo that layer, save that frame out as a file (composition ----> save frame as...) and then re-import it. If you drop it in as a new layer it should last the duration of your current comp settings.

Hope this helps. :)

[chrisg]

Hi artie,

That depends on how much camera movement you have. In this case, we have a tiny amount of camera movement, so we actually did do exactly what you said to create that sequence. We took the animation of the cop and then tracked a corner of the shot that was moving with the camera, then attached that motion data to our background. But if you have any real camera movement you want to render out the background.

Let me know if you have any other questions!