By Jim Tierney, Digital Anarchy
Nulls are incredibly versatile animation assistants. Not only can they be used to control other layers , but they can be used to control other nulls. If we want to use a null to animate our lights en mass, we need to attach the null to the nulls controlling the lights, not the lights themselves .
Create a new null that is in a center of the comp, which should put it in the center of the circle of lights. Turn on the null's 3D switch.
Now select all the nulls that control the lights, then parent them to the new null.
We want the lights to slowly move down the Cylinder and rotate as they're doing so. To do this, we will now just move the main null up to the top of the Cylinder. All lights will follow the main Cylinder up and we will set at a key frame for position and rotation of the main null.
We now move the Current Time Indicator to the end of the time line and move the null down to the bottom of the Cylinder. This will automatically set another key frame for position, and then we can set a keyframe for Y rotation: 1x135.
If we play this back, you can see the lights animating around the Cylinder.
We can also make some adjustments here allowing some of the lights to cast shadows and vary the intensity and color of some of the lights.