Friction!

Has anyone ever tried to implement friction or drag effects on an object before? It's a bit bizarre, the way physics works in SL, since there doesn't seem to be any friction with the air, although we do apparently have a terminal velocity anyway.

Anyhoo, I tried implementing a bungee cord, but without any sort of friction, instead of losing energy, the spring just started accelerating wildly out of control. I expected to end up dangling relatively statickly under the platform after a few bounces: instead, I ended up six sims away, face-down in the muck.

I tried applying a counter-force proportional to the velocity of the avatar, but that didn't seem to make much difference. It just made it more unpredictable. I hate math.

I actually did something similar for my marbles in the GameDev. I got a very very smooth oscillating effect in them. You are using nothing but ApplyImpulse, right?

Ever try making use of the Vehicle types without using llTakeControls? I haven't yet, but it seems to me that that's a ready source of friction...

I barely remember now, how I was applying the forces to the bungee-jumper... probably llApplyImpulse, or god help me, llSetForce.

I never thought of vehicles... huh, I'll have to prod around at that a bit, see what falls out. Thanks!

Well you'll notice from the standard linden airplane script you don't have to be in control of the vehicle for it's physics to apply or for friction to stop it. So basically you can use the vehicle engines to apply force via a vehicle motor in a pre determined method, like a bungee cord, then have friction and such take over according to your settings.

Friction is built into vehicle scripting... erf, forget the setting. If it's vehicles you're worried about, ask in the vehicle section.

Physical objects naturally have friction against solid surfaces, too.

My swarm script simulates friction via a timer without resorting to vehicle physics if you're interested.

Friction is built into SL already. Just change the material type and you're good to go. I've never bothered to quantify it, but Glass seems to be more slippery, as one would expect from the name alone.
Air isn't an object though, so it has no material type.
Hmm is friction different from atrition or however you spell it? My inglish si teh suck!

Yeah, someone posted this onto the Wiki, if someone cares to find the relevant articles, appears the material settings actually go down a whole load deeper, then usually thought.

-Adam

You mean this?
http://www.badgeometry.com/wiki/material

I knew someone would want that page some day.

Thanks, Apotheus, everyone.

I think where I was probably going horribly wrong was that I was, indeed, using llSetForce instead of llApplyImpulse. No wonder things got so out of hand.