Simple Animation: Placing Objects on Splines

For a long time we've been fascinated by cgi and computer animated movies. And it's not just the entertainment that we like, we're fascinated by everything from how to create good looking 3d models to the rendering pipeline itself. One very important aspect of course is the animation. That is creating subsequent frames or images that  viewed in succession give the illusion of movement. While creating good looking animations is an art and requires skills, we currently do not have, we did learn some tricks to create simple animations rather fast using splines.

We start by creating splines. Cinema4D offers different ways to create splines. From geometric forms like circles and squares to drawing "by hand", there are many ways to create and optimize splines. Once you've created a spline you can attach objects to it by using a simulation tag. Simply add a c4d spline tag to the object you want to animate and "drag & drop" the spline into the objects spline field. Now you can change the objects position along the spline using this tag.

Every animation consists of so called key frames and inbetweens. In the age of hand drawn animations, the animator would create the key frames and the inbetweens would be created by assistants. With computer animation you only have to create the keys frames and the inbetweens are created by the computer. E.g. if you create a key frame A where an objects position along a spline is at 20% and a key frame B where the position is at 50% the inbetweens from 20% to 50% will be created by the computer.

As an example we created a scene with three circle splines and spheres placed on them. We created pairs of key frames with the positions of the spheres at 0% and 100%. That means in the time between the key frames the spheres move one time along the circle. We placed the key frames apart from each other such that one movement takes about four seconds. Note that you can also place cameras on splines and animate the entire view by moving the camera itself!

We learned some of the basics of animation (mostly theory :D) from "The Animator's Survival Kit" by Richard Williams. Here is a video of  our "under water" circle sphere animation: