Home Made Crane

I'm having a humdinger of a problem.

I've designed a nice gantry style crane, it has a pulley that carts it
backwards and forwards, and that works fine. The magnet is working fine
and dandy, following its pulley about, and genrally acting like it
should.

until i need to drop the thing to pick up some stuff. that's where the
problem is. I've tried a couple of methods. the worst was trying to
create a train along a path ball-socketed onto the cart at one end, and
a ballsocket between the magnet, and the rope train thingy. this
failed, and ended up with the magnet trying to espcape through the roof.

the second solution, which kinda works (but extreemly badly) is when
the user hits the appropriate switch the length constraint is literally
turned off, allowing the magent to fall to the gound. and when they
release the switch, it come back on. pros: the crane picks stuff up,
and drops + falls, cons: if i ever see a crane working like that in
real life i'll be gone like a ferret with its tail on fire.

so the long and short of it, is that i need to either a) find a way of
dynamically altering the extra length property of the
phys_lengthconstraint, or b) find some other way around the problem.

please help me, i've been looking around the web for hours, with no joy.

HL2 problems go in the HL2 forum.

Well ... you could just attach the phys_lengthconstraint to a move linear entity (I forget the name, but there's one to move linearly) ... I'd suggest the "magnet" portion is a child of the moving entity as well. Other then that ... nothing else you suggested would change the length of the rope ... ever. If you want, Something that would make more sense ... since this how cranes actually work. You make a pulley system and make the rope the maximum amount it will ever be ... so the slack is hanging low and moves when the crane goes down and junk. It's possible, I've never done it personally so I can't give a detailed description.

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Blame it on Microsoft, God does.

well, i manged to get something working by sticking a pivoting phys_box
at the bottom of the crane cart, and using it as the parent for a
tracktrain and a cople of path_tracks. the magnet is then pivoted onto
the tracktrain. the only problem is that this all make the cable
effectively rigid, resulting in some strange effects (magnet revolving
at high speed around the bottom of the rope...) and adding a proper
phys_constraintssytem makes it worse.

i've had a look at the pulley system ,whihc i could wire up to a static
crane no probs, but it appears tha the pivots of the pulleyconstraint
are fixed, and wont move with my crane :sad: