The "Force" explained
Posted: Wed Aug 09, 2006 7:18 pm
Perhaps you have seen people talk about "The Force" in the contest threads, or on the official solution page. But what is it? And how do you use it? I'll try to answer these questions here.
Overview
"The Force" is a collective term for mechanisms that use a bug in the physics engine to generate momentum without using tension or other "realistic" means.
History
The first time the force was publicised was by BFC in a solution to Contest #1. He made a rotating "paddle" that accelerated indefinitely (or, rather, until it breaks) without any outside influence. It was soon discovered that the paddle could be simplified by just using 3 metal bars instead of 4. This version is pictured and described below.
Since then, the force has also been used with rubber and metal sheets to create rotating wheels and machines. One of the most impressive examples of "Force" usage is the "Force Clockwork" level, also pictured below. A longer and even more powerful paddle has also been developed.
How does it work?
The "Force" is generated when the ending point of a piece of material intersects another piece that exists on the same plane (ie. a metal bar and metal sheet combination will never produce any force). This happens in area 1 marked with the red circle in the picture below.
The physics engine tries to resolve this situation by moving the endpoint of the metal bar to the left. This movement propagates to point 2, which follows. It in turn affects point 3. Thus, the situation never gets resolved and the paddle starts its rotation.
Depending on the initial depth of the interpenetration and the overall structure of the paddle, the acceleration will vary. Some panels will continue to accelerate until they self-destruct after 2 or 3 full rotations.
Please ask further questions related to "The Force" in this thread.
Overview
"The Force" is a collective term for mechanisms that use a bug in the physics engine to generate momentum without using tension or other "realistic" means.
History
The first time the force was publicised was by BFC in a solution to Contest #1. He made a rotating "paddle" that accelerated indefinitely (or, rather, until it breaks) without any outside influence. It was soon discovered that the paddle could be simplified by just using 3 metal bars instead of 4. This version is pictured and described below.
Since then, the force has also been used with rubber and metal sheets to create rotating wheels and machines. One of the most impressive examples of "Force" usage is the "Force Clockwork" level, also pictured below. A longer and even more powerful paddle has also been developed.
How does it work?
The "Force" is generated when the ending point of a piece of material intersects another piece that exists on the same plane (ie. a metal bar and metal sheet combination will never produce any force). This happens in area 1 marked with the red circle in the picture below.
The physics engine tries to resolve this situation by moving the endpoint of the metal bar to the left. This movement propagates to point 2, which follows. It in turn affects point 3. Thus, the situation never gets resolved and the paddle starts its rotation.
Depending on the initial depth of the interpenetration and the overall structure of the paddle, the acceleration will vary. Some panels will continue to accelerate until they self-destruct after 2 or 3 full rotations.
Please ask further questions related to "The Force" in this thread.