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View Full Version : Expression help with helicoptor rotors needed.



JMarc
09-24-2004, 11:41 AM
Calling all expression gurus.

I'm trying to set up an expression that will control the speed of rotation of helicopter-type rotors using the Scale.X channel of a Null object, all using LightWave [8]'s built-in expressions.

I want to be able to scale the control Null from 0.0 to 1.0 and have the rotors rotate forward with a max speed(Scale.X=1.0) of 1080 degrees (3 rotations/second). So far I have come up with this:

mapRange([Rotor_Accellerator_Null.Scale.X],0,1,0*(Time),1080*(Time))

Which I applied to the rotors Rotation.H channel...but of course, this only controls the rotation direction not the speed. This causes the rotors to reverse their direction when I want them to decellerate.

When the Null object holds it's Scale.X value , this expression does, however, continue to rotate the rotors forward which is a feature I do want.

Could someone please point me in the right direction? Any help is greatly appreciated.