Tutorial #04 – How to Create a Bouncing Ball


-How to Create a Bouncing Ball-

Learn how to create the aimation of a Bouncing Ball just following this quick and easy tutorial, in the first part I also show how to create a simple rig for the ball! 😉

This tutorial is connected to the Lesson 05 where I explain the principles of TIMING and SPACING!

After the tutorial I suggest you do do the Exercise#1 “How to create a Bouncing Ball”Exercise_001

Bouncing Ball Tutorial RECAP

Let’s start with the Front view. We pose the ball in the air at frame 1 (approximatly 10 units on Y)Schermata 2017-03-17 a 13.10.06at frame 13 tha ball go back on the ground so we put at zero the Y translation in the channel box. Schermata 2017-03-17 a 13.10.17.pngLet’s take this line of the grid as reference for the ground. Schermata 2017-03-17 a 13.10.25.png-As I said in the Lesson 5,any bounce lose speed and force so the timing slow down at any bounce so do the high of the bounce-

So for the second bounce we slow down the timing and the ball will bounce in 10 frames instead of 12. So we go at frame 23 and we put the ball in the air again, but this time we reduce the height of the bounce! To be more precise, look at the value on Y of the first bounce. and reduce it a bit: the first bounce is height 10 units, so let’s put the second one 3 units less compared to the first one, so… at 7 units.Schermata 2017-03-17 a 13.10.48.png

Then we put the other key, where the ball go down again, with the same amount of frame it use to go up, “10 frames”, so we go at frame 33 and we put the value of Y at zero. Schermata 2017-03-17 a 13.11.01

We do the same for other 5/6 bounces. Always decreasing in height and timing.

This is a reference for the consecutive bounces:BOUNCING_BALL_guide

This is just an example:

1st bounce  12 frames – 10 height

2nd bounce 10 frames (+ 10 to go on the ground)  / 7 height

2nd bounce3rd bounce 8 frames (+ 8 to go on the ground) /  5 height

4th bounce 6 frames (+ 6 to go on the ground)  / 3 height

5th bounce 4 frames (+ 4 to go on the ground)  / 1 height

6th bounce 3 frames (+ 3 to go on the ground)  / 0.5 height

7th bounce 2 frames (+ 2 to go on the ground)  / 0.2 height

4th bounce 1 frames (+ 1 to go on the ground)  / 0.07 height

Now we have all the bounces in LINEARBouncing_ball_Linearso we need to open the graph editor and polish the curves!

In the graph editor we select the translation of the Y axis, and if you set the curves in AUTO TANGENTS or FLAT TANGENTS you can see that all the curves are smoothed, when the ball is in the air and also when it touches the ground.07.png

But we need to change this spacing, ’cause as I said in the Lesson 05, when the ball is in the air we have a SLOW SPACING (due to the combination of the gravity force/ the air resistance/ and the speed upward of the ball), but…when the ball is pushed to the ground and when it lift from the ground, we need to have a FAST SPACING08

So, the first thing to do is to select all the keys where the ball is contact with the ground (all the lower keys)09

and we switch the curves in Linear09

You can see now that during the contact the curves are straight so the movement is faster11

At this point we still need to adjust the curve before and after the contact, so we use the handles. But… if we select one handle and we try to move it, you can see that they move together12

So… we select again all the keys on the ground,and we click on the icon “BREAK TANGENTS”14

in this way we split the two handles and we can move them separately15

Now we can move them one at the time and we don’t have any influence on the other handle. So, let’s go to adjust the curve: we move them in order to have the part close to the contact much fast and slower the part in the air. The result we should have is this type of ARC16

Can you see the difference…just changing the Spacing?Bouncing_ball_Polished

Let’s now add the SQUASH and STRETCH!

As I already said also the Squash and Stretch decrease at any bounces, so in the first bounce we have a visible squash and stretch..in the last bounces the ball doesn’t deform it’s volume anymore.

We select the deformer, and we go to animate the Factor attribute on the right in the INPUTS17.png

let’s set a key at any bounce, in the lower and highest positions17b.png

At frame 13 we squash the ball decreasing the Factor value18.png

One frame before the contact, at frame 12, we stretch the ball, increasing the Factor value19.png

and we do the same one frame after the contact, frame 1420.png

Now we open the graph editor and we select the deformer factor21.png

We slow down the spacing of the stretch when the ball is in the air, so… the ball deforms when is close to the ground but quickly go back to its original shape when is in the air. We add two keys on the curve, one after the stretch and an other before the stretch: we click on the ADD KEY icon, we select the curve and with “central” click we add the keys22.png

we move them down, close to the original size, without the stretch23.png

And we do the same for 3/4 bounces, the deformation is each time smaller.

Bouncing_ball_Squash&Stretch

Ok, now we can add the forward movement.

We set a key at frame 1 and an other key at the end of the shot, at frame 9024.png

At frame 1 we move the ball on the left screen, just out of the frame25.png

and on frame 90 move it on the right screen26.png

Let’s go in the graph editor and we select the axis with the forward movement. The curve is Linear at the beginning, and Flat at the end27.png

we add an other key around frame 8028.png

move this key on a value more close to the last one

So now the movement start fast and slow down at the end!

Now we just need to adjust the rotation of the ball during the stretch, because if you look at the ball during the squash and stretch you can see that righ now, when the ball stretch, doesn’t follow the Arc path, is straight but should bend on right and left

We can adjust the rotation using the deformer.

We select the deformer and we set a key on the rotation of the deformer on any bounce, in the contacts and in the highest positions. For all the bounces where we have the squash and stretch!31.png

and then we just rotate a bit the deformers on the key before the contact and on the key after the contact

and…THAT’S IT!

Bouncing_ball_Forward_movement

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