Shadow-ONLY light creator

Hey there,

I would REALLY love a script that created a "shadow-only" light pair in a more "user-friendly" manner.

Basically, the script should create two lights in the exact same space, one "primary" light with shadows turned on, the other ("secondary") idendentical to the first expect for the following parameters: shadows off, and a multiplier inverted from the primary (ie. -1.0).

I imagine that that part on its own shouldn't be too difficult, however, there are a couple of functionality issues that would really make this script sooperdooperawesome:

The secondary (inverted multiplier) light should come in in a frozen state. It should then have all of it's parameters locked to those of the primary (shadow-casting) light... So if I change the cone angle on the primary, the secondary matches, if I change the light type (ie. spot to direct), the secondary matches, if I change the position of the primary, the secondary matches, if I change the color of the primary, the secondary matches, and if I change the multiplier of the primary, the secondary matches... only in the inverse. Shadows on the secondary would always remain "off".

I am attaching a max (9) file for anyone who wants to check out how these lights work. They're really helpful for lighting huge exterior shots.

Anyhow, if anyone wants to take a stab at this one, I'd be EXTREMELY appreciative, and suspect I wouldn't be the only one.

Cheers, and good luck!

-Brittnell

Ps. Just in case it isn't immediately clear what is going on in the attached scene, no light is coming from the spots, only from the white ambient of the environment... Yet there are shadows... Spooooooky!