Pendulum
Last week, I stopped by the Afton stronghold of the Brainiacs (SL location link). Like Oneironaut Escher's Cannabis Carnival (SL location link), Brainiac's HQ is a great place to drop in and have your mind blown.

I was particularly intrigued by a one item there: the Spirograph. Basically, it was a simple physical pendulum. The basic operation required no scripting. Instead, it ran indefinitely under the game's physics engine. The construction of such a device is simple:

1. Create an anchor object several meters above the ground.
   
2. Create a pendulum object a few meters below it.
   
3. Select both of the objects.
   
4. Under the Tools pulldown, select Make Joint and Point-to-Point.
   
5. Select only the pendulum object.
   
6. Turn on Physics.

And that's it! In order to see the trails, you'll probably want to add a simple particle script to drop particles from the pendulum bob a few times a second. (I'm too lazy to post said script. I just ripped it off from a Watermelon Gun bump, anyway.) Then, give it a nudge. The mechanism is frictionless, and will run indefinitely from a single push.

The pictures below were made with a 20 meter long pendulum. (The Make Joint command has the same limitations as Link Objects. As such, I had to create a "rope" to bring the physical pendulum close enough to the anchor to be joined.) I went ahead and made the whole assembly transparent for the pictures. As a further refinement, a script was added to periodically deliver a small, random impulse to the assembly every two minutes. This served slightly perturb the motion every so often. The results were kind of pretty, if I do say so myself.


Posted by Moriash Moreau at 2:34 PM