unlimit = [2000, -1000]; // Using this to give clamp some freedom
null1 = thisComp.layer("Null 1").transform.position + value; // The value in here is 0, 270
ground = [207, 630]; // This is the left/right and up/down barrier
clamp(null1, unlimit, ground)
You might try using a clamp() expression.
You could read the position (and other attributes) of the Null into your leg layers instead of parenting them.
Then give them limits.
I built a sample comp with a Null 1 and a solid. You'll need to adjust your settings, but it should be fairly obvious what the constraints need to be.
Trent Armstrong - Creative Cow Leader
http://www.dallasaeug.com
