Bouncing Ball Tests

As an introduction to the principles of animation and to the 3D modelling software, Maya, this week I've been attempting the bouncing ball test. I plan on experimenting by putting some of the principles in practice, such as 'Squash & Stretch', 'Anticipation', 'Slow in & Slow out', and most importantly, 'Timing & Spacing'. Hopefully it will also help me learn the interface for animating in Maya.

I did a few bouncing ball tests using Toon Boom Studio in my free time last term - however I did not pay much attention to the laws of physics:

In fact, the only principle that's obvious to me here is 'Squash & Stretch', which I've been quite liberal with, and on the whole, the weights of these balls seem totally unclear (note the yellow one flying into space). As a first try, I was content; but now I want to move on and do this test correctly by doing some research prior to animating.

I did some searching on youtube to see what I could find in terms of live action bouncing ball tests, and I came across a few I thought I might be able to use as references.

Although it only represents one particular type/weight of ball, I found this video to be very clear - most of the action is on screen (as opposed to off camera), and the white band around the ball will be helpful when I learn about rotation later on.

I liked this video for the sheer variety of balls he used to test with. However there is a big fault in that the surface he's using is uneven, which was most obvious when bouncing the exercise ball. This was disappointing because, in my opinion, the exercise ball had the most interesting bounce!

After seeing these examples, I wanted to make my own reference video - which proved to be more challenging than expected! 

My first problem was that I don't own many balls, hence the fruit and vegetables, so I only really have one reference clip here. Also I think the quality of the video would be improved by having more natural light, so I should have started filming earlier on in the day. I had wanted to experiment with different surfaces (ie. a carpet) to see how it would impact the bounce, however it took so long getting the rubber ball to be in shot for the duration of the bounce test that my patience wore thin!

I wanted to see the path of motion of my rubber ball, but the software I wanted to use to do this turned out to not be compatible with macs. My solution was somewhat longwinded - I took many, many screenshots of the video, put them into photoshop and started merging them together:

As you can see, the ball path is extremely faint, and as the layers started building up it began to look very messy. I eventually had to delete everything and start with a new idea - seeing how high the rubber ball was bouncing. I watched the video back and started taking screenshots when the ball was at its highest and its lowest. I then put these images into photoshop and started the editing process again.

These technique turned out to be a lot less messy! It also gave me a very good idea of spacing - I helped visualise this better by creating lines on the side of the image to get a better idea of idea of distance between the bounces.

The next step was Maya. Before trying to replicate the bounce of my rubber ball, I firstly wanted to try to get used to the interface by creating a simple and (hopefully) realistic ball bounce. I started by putting in my keyframes when I wanted the ball to hit the ground and when I wanted it at its highest, then adjusted the position of the ball accordingly. The fun part was playing around with the graph editor to give the ball some weight and realism.

I played with the tangents to get some nice curves - my bounces were most effective when I broke these tangents so I could achieve a 'fast in/fast out' as the ball hit the ground.

I also found that free tangent weights affected the shape of my curve quite significantly.

My first attempt at an 'anticipation' using the graph editor.

I liked the finished result; it wasn't accurate but it helped me put the principles 'Timing and Spacing', 'Anticipation' and 'Slow in/Slow out' into practice. Using a reference next time will hopefully make the bounce more realistic and give the ball some much needed weight!