Lesson #6 – Slow In & Slow Out

Let’s continue with the Principles of Animation … let’s see how to smooth our animation with “Slow In & Slow Out”! 😉

(In the lesson I used the rig “Pete” by Long Winter Members)


Slow In & Slow Out RECAP

The Slow In and Slow Out principle or Ease In and Ease Out is so important but also really easy to understand and put in practice!

The concept is:

 an object doesn’t have a constant speed during a movement. It will have an acceleration at the beginning and a deceleration at the end


So, will starts slower, SLOW IN, increase the speed in between, and ends slower before to stop SLOW OUTslow_in_slow_out_03.png

To add a Slow in and Slow out to a movement we need to change the spacing of the in-betweens at the start and the end

If we have an object that moves from A to B and the tangent is linear, so we don’t’ have any variation in the speed, we would have a stiff and mechanical movementslow_in_slow_out_06.png

But…if we have the same movement, but we just change the position of the in-betweens  near the first key pose and the last one, the movement result more soft, smoothed, and realisticslow_in_slow_out_07.pngslow_in_slow_out_08.png

Always remember that we are doing cartoon, so to have a more appealing animation, we can also exaggerate this principle!slow_in_slow_out_09.png

This doesn’t mean that you have to encrase the timing of your animation to have more in-betweens at the start and the end. It’s always based on the speed of your action. In a faster action you will have few frames but you still can manage them in order to have a slow in and slow out


Changing the curve in the Graph Editor is very easy to achieve the result we need, using a FLAT tangents we already have a smoothness on the extremesslow_in_slow_out_11.png

if we use the SPLINE tangents we can reach the same result using the handlesslow_in_slow_out_12.png

We can also add an in-between near the first pose, and an other near the final pose, and move them on a value closer to the extremes, until you don’t reach your desiderata effectslow_in_slow_out_13.png

But…keep attention!

When you adjust the handles don’t create this type of curve, where it goes on a higher (or lower) value compared to the last pose valueslow_in_slow_out_14.png otherwise you will have a backward and forward movement. So, if you just want to smooth the forward movement, the curve should be like this one belowslow_in_slow_out_15.png

slow_in_slow_out_16.pngSlow_In_Slow_Out_Pendulumlook how smoothed is the movement on the two extremes. SLOW FAST SLOW


with the same key poses and timing, but with a different spacing, we would have a linear movement, that is really unrealisticSlow_In_Slow_Out_Pendulum_Linear

As you can see in the graph editor , I created a Loop animation so I have the two poses at the beginning and the end with the same position, and an other extreme in the middle with the pendulum in the opposite direction, in this case the tangent is LINEAR, that’s why we have this stiff effect, the interpolation has a uniform velocity, so all the in-betweens have the same distance between each other

…just switching the same curve in FLAT, the spacing of the in-between change and the movement is more realistic

If we create the same movement with a character, the principle doesn’t change, we will always have a movement that start slow, takes speed and slow down again

Slow_In_Slow_Out_Character_FrontSlow_In_Slow_Out_Character_SideSo … use this principle, with all its variations, for your objects and characters animations!  It’s easy and quick to achieve and your animations will change a lot! 😉


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