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Setting up a trebuchet

May 12, 2009 at 8:38 PM


I'm trying to create a trebuchet but having some issues.  So far I have...

* Horizontal beam.  This is pinned to the world with a FixedRevoluteJoint which is about 3/4 along the beam.  This is supposed to let it rotate freely.

* Weight.  A small weight at the right hand end.  It's mass is 50 and it's connected to the end of the beam with a PinJoint and it's target distance is 50.

* Ball.  A ball on the opposit end.  It's connected with another pin joint.  It's mass is 1 and target distance is 60.

The idea is as soon as I enable everything the weight drops pulling the ball around then on a button press I'd break the joint and the ball would go flying off.  Trouble is if I do let the above go the simulation just goes mental and everything starts spanging around. 

Anybody got any ideas on the best way to set one of these up?





May 12, 2009 at 11:02 PM

Have you set the correct collisiongroups on the geometries? The parts that must not collide, must have the correct collisiongroups.

If you still have problems, you can contact me by clicking on my username. If you send me the source code I'll take a look at it.

May 12, 2009 at 11:33 PM

That reminds me, I played a game with a trebuchet some time ago:

You could model your trebuchet after that one. It seems to work great.