Before we can start animating in Blender, we have to setup our animation length and fps. So how do we set these and what should we set them to?
To change the animation length in Blender:
Go to the output properties tab in the right-side properties panel and find the frame range section. Here, change the End frame number. By default, Blender is set to 24 fps, meaning that every 24 frames you add to the End frame number adds one second to your animation length.
To change the fps (frames per second) in Blender:
Go to the output tab in the right-side properties panel. In the format section, change the frame rate to any of the available fps options.
In the rest of this article we'll go over animation length, we'll also touch on how fps effects it. Then we'll do a fairly in-depth discussion on which FPS to choose and why.
Same place as you set it. You can take the end frame and subtract the start frame and divide it by your fps to get the length of your animation in seconds.
As an example if we take the default animation length which is 250 frames and then divide it by the default frame rate which is 24 fps we'll get an animation length of around 10 seconds.
In the timeline you can see a light gray area surrounded by a darker gray area. The light area is your animation. Any area outside of it is not part of your animation. Such as before frame 1 and after your end frame that is by default set to 250.
In the timeline, you can go to view and set "show seconds" to view the length in seconds along the timeline plus the number of frames at any particular place along the timeline.
There are a few things we can do to change the animation length. The main way is to adjust the start and end frames.
We can also change the length of the animation indirectly by adjusting the frame rate. This is important to note as blender doesn't automatically change the start and end frames when we change fps. This keeps the number of frames consistent but we just flip through them faster.
FPS is short for frames per second, and it is the number of images per second your animation or movie is playing at. Your display is updating at this rate. It's the number of images that a video file will show per second.
Since we define animation length by a start frame and an end frame in Blender when we change the fps of our animation, we are going to change how quickly blender flips through that set frame range.
We'll still render all of those frames it's just that when we playback the video more or less of those frames will be cycled through per each second.
24 fps is considered standard for cinematic content. 60 fps is smoother and maybe not as standard. 120 fps is slightly smoother than 60 fps but is likely overkill for most video content and the same goes for anything above.
Another caveat of higher fps is that it will result in longer render times if we keep our animation length the same. For anything higher than 60 fps we'll need a display with a refresh rate higher than 60hz.
Note that in most cases 60 fps we'll give us the smoothest results since many monitors only go up to a 60hz refresh rate and any higher fps won't result in a noticeable difference.
Of course, this will likely change in the future and 120 - 140 fps will result in a noticeably smoother result if the video is being played back on a monitor with a refresh rate of 120hz and above.
In general, though for video content we don't really need too high of a fps and anything above 60 fps is usually overkill. For cinematic content 24 fps is the standard that has been used for a long time.
You may have noticed that the fps dropdown doesn't let us set a specific fps but has a list of preset values. The reason for this is that each fps either corresponds to a a standard value used in film or for any other common use or because it matches a refresh rate.
Another aspect we might need to consider when choosing our fps is if we're used film content that contains lights. PAL vs NTSC, old standards. PAL runs at 25 FPS and NTSC runs at 30. This depends on the alternating current frequency in your country.
In the US it is 60hz and in EU it is 50hz. The fps needs to be dividable with the alternating current frequency in the country you are recording in or lights can flicker in your video.
To avoid this, you can use only LED lights and sunlight. Other traditional light sources depend on the alternating current frequency and flickering can occur. If we are not using filmed content, we don't have to worry about this. For YouTube 30 fps is standard but 60 fps is also used. 24 and 25 fps are also available.
If you are unsure use 30 fps if you are in the US or 25 fps if you are in the EU.
Now we should have a decent understanding of fps in Blender. We've gone over a few simple things like viewing the length of our animation and setting the timeline to seconds. We touched on animation length and how fps effects it.
We've also gone over some general information about what FPS to choose and when to use them and why the options available are seemingly arbitrary. By matching our footage fps with the frequency of light fixtures or displays we should be able to avoid flickering in our videos as well.
