So I've got a decent idea for a gimmick for a HL2-DM map, using a pendulum attached to the base of a larger pendulum (aka a double oscillator). I even built one that works pretty well, swinging down twenty stories and crushing any hapless player caught beneath it with the force of a speeding train. Here's a shot of it from my test map (it's taken in Hammer... so shoot me):

Anyway, my problem is that it doesn't swing long enough, reduced to hanging limp after about 30 seconds. If you've never seen one of these things in real life (they're much smaller of course), a well-oiled one can continue swinging for several minutes at the minimum.

Since the pendulum is intended to be a major hazard in the trench it swings through, I need it to continue swinging for a long time at a speed fast enough to squish a player. I was hoping someone on these boards could offer me one of the following:

• Some way to reduce friction to zero for the entire setup. As far as I can tell, the hinges already have zero friction, so the energy loss must come from somewhere else. This is by far the optimal solution.
• A setup that inputs energy into the system somehow to keep it moving, without causing unnatural motion.
• And the last resort, a control system that can quickly reset the double pendulum to its original position.

I've considered those options, and have actually built a test case where a phys_motor cranks the large pendulum back into position. Unfortunately, it's a somewhat jerky motion and I have yet to dabble in angle sensors so I have no way of automatically initiating it when movement ceases (without just using a timer).

Using thrusters is what I'll probably end up doing if no one has any ideas about reducing friction. It seems like this sort of thing should be relatively straightforward, but it's possible that all func_physbox objects are affected by air resistance so much that they will always come to a halt.

The devil's in the details; working with either of those options requires a complex cluster of dependent entities and a ton of fine tuning to get working perfectly; I was hoping for an easy way out.

That's the entity I'm using, and I have the friction in both of them set to zero (default). I'm going to try assigning everything to a constraint system, maybe the "fighting each other" that's described in the help is causing energy loss somehow.

? quoting Leperous

/offtopic: One of my maths professors proved that several pendulums attached together can be made to stand upright if oscillated fast enough. I wonder if the Source engine realises this

Do you mean he actually located a local minimum in the potential energy curve? My experience is that Math Profs tend to be a bit out of touch with reality

Even if there is a local minimum, there could well be enough energy in the system to get it over the activation barrier one way or another...

what u could do is use some kinda prop_dynamic model becouse the dynamic models never slow down and make a func_physbox around it and set the flag " debris dont collide whit player or other debris . then make the prop_dynamic parent to the physbox . ingame the dynamic model will just push back every thing that blocks it .