crankshaft - linking object movements

Best idea is to think of a crankshaft and a piston - both are multi prim objects (could be a single object) - as the crank shaft rotates the piston rises and falls - how could I do this? any ideas?

well if you're bored and like watching things break you could make the piston physical, and drive the shaft with a script that uses llSetRot (in small increments), llTargetOmega (if the shaft is also physical), or llSetTorqueAndForce (also requires physical) or even llApplyRotationalImpulse (like torque but not constant)

or just do what everyone else does, and use llSetRot for both, and timing messages to get it in synch.

Yawn - zzzzzz - no I think the common timer might be the way - thanks

I'm not quite sure on the "durability" of the havok engine these days, but many, many moons ago (2005ish) when I first started messing with the physics engine most "simple" machines could cause a sim to crash. An experiment with creating a crankshaft and 8 pistons resulted in a sim's physics FPS dropping to below the 10FPS mark, and creating a physical chain with 12 linked torus' (torii?) caused the sim to crash completely.

Now, granted that the havok engine's been improved since then, but, going by some recent projects where I tried to get small objects to move with physical forces, there's a lot left to be desired within SL's physics system.

actually physics is massively improved with H4... and I know of a group that works with pure physics objects. they've managed to come up with non-scripted perpetual pendulum. but generally if you want it to work, right, and not have to fool with it... just script it.