View Full Version : making a crane

04 April 2008, 12:13 PM
hellow all,

I'm working on a crane that is on a boat. Only the thing now is how can i animate the cables and the heavy tuff.

i added 2 pics to make it easyer for me to explain.

Well as you maby can see, when the crane goes up the blocks stay liniar. ofcourse the have to hang down cause of there weight.

Now is my question how can i let those 2 blocks hang like they are 3-4k kg. ( they wont move by a little wind cause the blocks are 10M wide)

an other thingy is that i actualy want to pull a cable then the whole crane goes up. ( i probably need to constrain something)

can some one give me some tips or hint?


04 April 2008, 04:21 PM
My best guess is Hair curves on the cable and constrain them to the blocks. Make the blocks rigid bodies and up the mass of them to the weight that looks about right. There might be a better way, but thats my guess. Im still a newb when it comes to dynamics.

04 April 2008, 09:43 PM
Have you ever played with maya nCloth? I just threw together a quick test of a crane.

1) Make the crane nCloth passive
2) Make your rope nCloth
3) Make your objects that bounce around on the end of the rope nCloth (crank the rigid value of these objects to 1 or higher)
4)Select the vertices on one end of the rope and select the vertices on the crane and create an nCloth constraint of "Component to Component", now do the same for when the rope meets your hanging object.

You will have to tweak the mass of your objects and the stretch res. and all that of your rope.

Sorry for not going into great detail kind of rushed, but if you wanted to use nCloth this is the route I would go.

Let me know if you have any questions!



04 April 2008, 10:45 PM
Hair is a lot harder to setup and I would probably only use hair if you need it to sag otherwise you can use rigid constraints. Use a spring constraint for the pully, a hinge constraint for the arm and a nail for the ball and chain. Just remember that each object that has a constraint has to be either a passive or rigid body.

04 April 2008, 06:42 AM
Well at first i dont have Ncloth. ( cant find hair either... ( i belive thats in the other package we dont have here))
Ill try to do the thing with the constrains.

ill come back to you in a few/.

well im trying with the constrains but Aikiman i dont know what your talking about.

Use a spring constraint for the pully, ( what you mean with pully?)
a hinge constraint for the arm and a nail for the ball and chain. A hinge constrain??? never heared of that.
Just remember that each object that has a constraint has to be either a passive or rigid body. ( is there any difference between these? just a bit of a noob with this)

04 April 2008, 08:43 AM
OKI it worked

this is what i did:

on the end of the crane i have made an locator on that lockator i putted a point constrain.
then i made a locator with a point constrain of the clostest vertex of the cable to the crane and made the cable a child of the locator.
then i made an other locator and maded the wieght ( the hook) an child of the locator.
this locator i point constrained to the cable with an Y offset to get the wieght at the right height.
and now it works :D

04 April 2008, 09:05 AM

Next problem :P

i want to pull the crane up by pulling the cable.
i did the following thing:
i made a cable ( wich you can see the little black line above the red one ) i putted it full with joints. And conected the end ( where the little red arrow is ) with a pointconstrain to the rest of the crane. ( the point constrain was made from the joints to the crane) the joints go in the same direction as the arrows on the red line. So i started at the frame and went to the A-frame
when i moved the crane up you can see the cable went up as wel ( this is what i rendered)
what i actualy want is when i pull the cable ( at the A-Frame ) that je cable stays conected to the rest of the crane but pulls him up. But he has to rotate at the correct point.

I hope some one can give me some hints or tips..


*** Ow reminder that i dont have Ncloth or such things dont have that maya version ***

06 June 2008, 11:54 AM
well the explanation i made about the constrais suck!.. i had to do it over but it didnt work the way i wrote it down.

i made an set driven key for it.
since i know the degree the boom wil go up and i know the cargo always will be 90 degree with the floor its easely to make an expression.
The other problem i have also solved with clusters at teh end of the cables.

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06 June 2008, 11:54 AM
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