My third project for the semester also happened to be my last college project ever, so I decided to go out with a bang. I really enjoy computer games, and one of my favorites is Half-Life 2. Half-Life 2 has a very sophisticated physics simulation system built into its game engine, allowing objects to interact realistically with one another in the game without specific programming for that interaction. For example, in older games, to have a rubber ball bounce after being dropped, it had to be programmed and animated to bounce in that precise spot and would play exactly the same way each time. In Half-Life 2, a rubber ball can be dropped from anywhere, and will bounce and roll realistically every time without any specific coding or animation.
An add-on modification was created for Half-Life 2 called Garry's Mod(or GMod for short) that allows players to place objects and items from the game into blank levels and arrange them in a variety of ways - welding them together, attaching them with ropes or elastic bands, adding balloons or thrusters, etc. Players can fabricate any number of bizarre creations using Gmod, from forts to planes to catapults. Having seen what some other players had done, I decided to use Gmod and Half-Life 2 to create a virtual Rube Goldberg device, which is a machine or series of machines that accomplish a very simple task by the most complicated method possible.
For my device, I decided that the most mundane task in the game world would be killing a zombie. With this lofty goal in mind, I set to work.
Garry's Mod allows the player to load a number of different areas to work in, but I chose the default: a wide open area between two warehouses, with a big grassy field, concrete lot, some sidewalks, and a pond. Here's some pictures of the level before I set to work (just ignore the levitating dumpster, random crate and bathtub-zeppelin I made while messing around):
Originally, the first part of the device dropped a huge metal dumpster onto some explosive barrels to cut the slingshot loose, but, oddly, the dumpster only caused the barrels to explode occasionally at best.
So, on the advice of some random guy on the Internet, I switched to a car to ensure maximum dropping power(the car always lands hood-first, so its inertia hits across a smaller surface area and ends up doing more damage than the wider dumpster) and used another wooden crate instead of the barrels, since the crates are a lot more fragile.
Selecting the ammunition for my slingshot also took some time. I tried a lot of things: car batteries, a toilet, a sink, explosive oxygen tanks, a dead soldier, even sawblades. But, the tried-and-true AMF Lanes Bowling Ball ended up being the best and most accurate.
The second part of the machine was fairly simple - using large metal doors like dominos. I spread out quite a few of them, to maximize the chance of the bowling ball hitting at least one. Sometimes the ball would fly right over the doors, though, which was pretty anticlimactic.
The third part of the device got complicated - I tied a tire to the last domino-door and put it on a platform above it. Then, I put another tire in front of the first, and tied it to a huge steel girder sitting on a platform above that. Finally, I welded some harpoons onto the front of the girder and built a ramp for it and for the tires below it to slide down, and put a pile of explosive barrels on the ground where the harpoon hit. So, when the last door falls, it pulls the first tire, which pushes the second tire, which pulls the girder down its slide and into the barrels.
I went through several possible endings for the machine. My favorite released a car tied to a bunch of balloons and sent it floating upward into a spinning carousel covered with sawblades, destroying the balloons and dropping the car back down onto some explosive barrels, which in turn launched the final sawblade into our hapless zombie victim. However, this set-up never really worked consistently, so I scrapped it.
Instead, I used another giant girder, roped to a concrete crossbeam, and used it like a giant battering ram. In order to add a real photo finish for things, I welded a sawblade to the end of the girder, creating what I like to call the Pizza Cutter of Doom.
And, finally, the view from the zombie's position:
Whee!
Watch the video - version 1 - version 2 (aka Bisectorama)