Slow down by a particular function?


Is there any way to slow down parts of an animation? I thought i could do something with “free time” or “time loop,” but I’m currently stumped.

Note: I’m in 30fps, if my time references are confusing.

I’m trying to animate something like a wheel of fortune. So what I did was make the wheel and rotate a certain integer of 360 degrees at some time (I was originally just going to do this for 30 frames and then time loop it, but I had a weird problem where it would freeze on frame 4, 8, etc. That’s unrelated though).
Then, I made a clicker object that rotates back and forth, and I time looped that ever few frames so it’s synced with the wheel spinning.

Now, I have a wheel that spins at a constant speed for a few seconds and has a synchronized clicker object with it. I want to make the wheel slow down smoothly and eventually stop. I could do this manually by defining several intermediate points (i.e. 720 degrees at frame 30, 1000 degrees at frame 60, 1100 degrees at frame 90, etc.) but I think this will be jarring.

Is there any way to make the animation run at 1x speed to 0x speed over a certain period of time?


i tried as hard as i could, and i only came up with this

fromspintostop.sifz (1.48 KB)

is that right… :question:


Oh, interesting. You messed with the speed parameter?

I think that’ll work, thanks!


I only it use time-line and loop. Your only have to move it them keyframes in time-line


Oh, wait!! I let me clarify that one a bit! :blush:

First, and this is really important, i only tested it when the spin starts at frame 0
and it doesn’t work properly if it starts from more than frame zero
So probably shouldn’t use it at the moment

And, yes, i was trying to mess the speed parameter
it doesn’t work…

But something that i notice when playing with it is that
Speed parameter stops the animation at 0,5 , and reverse it back if it goes less than that
So i thought, can linear do that…?
And this is what i actually did in that file…

(Careful though, converting a value will lose all of it’s waypoints!!)

The linear Rate starts with 720 and ends with 360 at a certain frame (in clamped interpolation)
and it does work just like speed parameter, it stops running at the half of the rate
but then, it starts running again at normal rate of 720 once it passed the waypoint that slows it down

so then, i have to use the min-max thing

That is range parameter, and i set the max at a certain amount
so it will stop after the angle reaches over the max amount

to set the max amount, i checked the Link (that has the linear conversion) after it stops spinning (at the second waypoint)
then i typed that number into the max amount

Sorry to make the file look confusing, i forgot to remove the speed parameter… :unamused:


Alright, i’ve found something else to make up my mistake

but… i don’t know how to explain this one… :neutral_face:
it uses combination of several interpolations and Temporal Tension (It’s Hard… to understand :open_mouth: )
i can only mess with Temporal Tension though since it’s not TCB (that green dot)
Both of the waypoints uses TT by the way

at least it can be moved anywhere this time…
just get the angle right though, otherwise it might look a bit rough

tt-spintostop.sifz (1.39 KB)

to check the waypoint’s details, just right click on it and click “Edit”


Oh, man, this seems really complicated. But the basic idea is the mess with “temporal tension?”

It looks like you set the initial Tension=2 and Temporal Tension=-1, then final Tension=0 and Temporal Tension=1. And you had a rotation change over the effect? This causes it to speed up in a direction, then reverse and slow down, so I should just cut out the first half?

Can I use this on a time loop parameter?

For example, imagine I draw a stationary circle near one of the endpoints of your bar and I wanted it to move out of the way and change color when the bar approaches it. Since the bar is slowing down, I want the color changes to slow down by the same amount, so can I use a time loop layer with the same temporal tensions?

I tried this, and it kinda works, but changing the time loop layer isn’t really working for me. It doesn’t seem to change the speed of the loop, only the time between loops. And then something wacky happens near the end?

But if I’m only changing the bar’s rotation, starting at temporal time=0 and ending at temporal time=1 seems to work!


As much as i can try, the first three parameter of TCB don’t have any effect at all if there is no TCB interactions within adjacent waypoints
the file from TCB in Synfig wiki page shows that it uses three TCB waypoints to make up that effect

Also, i think i rotated it in wrong direction (it was counterclockwise all the time)
although to make sure whether it works or not, i can only rely on this graph panel

Notice that i decided to change the interpolation in to ease in/out to saves time,
Waypoints other than TCB won’t gain any effect from changing the first three TCB parameters,
but Temporal Tension can still affect these types of waypoint


I figured out another way to do . . . something . . .

In the group parameters, I right click converted “time offset” to linear, and then I messed with the “rate” value.

Note sure exactly what I did because it ended up having a strange reversal effect in the last few seconds, but with a bunch of attempts and a few duplications I was able to get it to work a little bit . . . if anyone’s curious I’ll post a rendered file when I have it.


sure, i do curious :exclamation:

linear always does that though, it all depends on time that it was on (i also had the same problem while using it)
Based on wiki, linear works like this --> Final Value (Link) = (Rate X Time at the moment (in Seconds) ) + Offset


Alright, here’s my scene! The motion blur isn’t amazing (my first time using it) but I think the slow down effect worked.

Basically what I did to cut out the reverse motion was to create 2 wheels (moving one on top of stationary one that sits at the final frame of motion), and turn the moving one off right as it starts to reverse.

Oh…it won’t let me attach the rendered file. Well, I guess I’ll just post my mess of .sifz . . .

Oh…the sifz is too large…Well, sorry :frowning: I’ll try to remember and come back here in a few months with a link to the full video when I post it on youtube :slight_smile:


yeah, that’s what i thought would be one of the few solutions…
set the linear ones to off at the next frame before it reverses while the ‘stopped’ state of the wheel is awaiting there is quite an idea :bulb:

sure, no problem! :slight_smile:
you seem to put a lot of work into that, something that is really difficult for me to do… :unamused: