3D Solar System of Rotating Planets and Moons - Page 11

The Orbits (cont.)

Assigning the path controller basically animates the object (our planet) travelling on the path (our circular orbit) from 1 - 100% over the duration of the animation. This means, that all of our planets are going from 1 - 100% over the 100 frames that makes up this particular animation. We need to change that, and give them different rotation lengths.

First, we need to adjust the length of the entire animation. Press the TIME CONFIGURATION BUTTON and set the ANIMATION END TIME to 200 frames.

What we need to do now is adjust the length of the time each planet takes to go around their respective orbits. We'll start with the biggest orbit first, just for something different.

Select planet 5. If you look at this next image,

You'll see I've placed arrows next to two circular shapes at the bottom of our animation bar. This is the TRACKBAR, and is a new feature in MAX3 designed to help make quick adjustments of keyframes. In this case, what we can see are the start and end keyframes for our selected planet. We can see it starts at frame 0 (the half circle on the left hand edge) and finishes at frame 100 (the other keyframe). Move the frame slider over these keys and you'll see the action stop right where the keyframe does.

What we'll do is click on the end keyframe and drag it across to the right to frame 200. We can keep track of the frame number by looking at the area I've circled in red in the image above. It will change and tell you what is happening, and what frame you are up to.

Once you've dragged it out, press play. You should see the planet now travel slower, reaching its destination at frame 200, the end of the animation.

Now see if you can adapt this knowledge you've learned to change the other planets orbit end times to the following:

Planet 1: frame 40
Planet 2: frame 60
Planet 3: frame 90
Planet 4: frame 130

If you press play, the planets should rotate once at different, staggered speeds.