Generally, you do a lot of intermediate renders of different frames in your animation to check for timing, lighting, placement, materials, and so on. At some point, you are ready to make a final render of the complete animation for publication.

There are two approaches you can use when making a movie, or animation, with or without sound. The approach you should use depends on the amount of CPU time you will need to render the movie. You can render a “typical” frame at the desired resolution, and then multiply by the number of frames that will ultimately go into the movie, to arrive at a total render time.

If the total render time is an hour or more, you want to use the “Frame Sequence” approach. For example, if you are rendering a one-minute video clip for film, there will be (60 seconds per minute) X (24 frames per second) or 1440 frames per minute. If each frame takes 30 seconds to render, then you will be able to render two frames per minute, or need 720 minutes (12 hours) of render time.

Rendering takes all available CPU time; you should render overnight, when the computer is not needed, or set Blender to a low priority while rendering, and work on other things (be careful with the RAM space!).

Direct Approach

The Direct Approach, which is highly not recommended and not a standard practice, is where you set your output format to an AVI or MOV format, and click Animation to render your scene directly out to a movie file. Blender creates one file that holds all the frames of your animation. You can then use Blender’s Video Sequencer to add an audio track to the animation and render out to an MPEG format to complete your movie.

Frame Sequence

The Frame Sequence is a much more stable approach, where you set your output format to a still format (such as JPG, PNG or a multi-layer format). Click Animation to render your scene out to a set of images, where each image is a frame in the sequence.

Blender creates a file for each frame of the animation. You can then use Blender’s Compositor to perform any frame manipulation (post-processing). You can then use Blender’s Video Sequencer to load that final image sequence, add an audio track to the animation, and render out to an MPEG format to complete your movie. The Frame Sequence approach is a little more complicated and takes more drive space, but gives you more flexibility.

Here are some guidelines to help you choose an approach.

Direct Approach

Short segments with total render time under one hour.

Stable power supply.

Computer not needed for other uses.

Frame Sequence Approach

Total render time over one hour.

Post-production work needed:

Color/lighting adjustment

Green screen/matte replacement

Layering/compositing

Multiple formats and resolutions of the final product

Intermediate frames/adjustments needed for compression/codec.

Precise timing (e.g. lip-sync to audio track) needed in parts.

May need to interrupt rendering to use the computer, and want to be able to resume rendering where you left off.