Alright, so here's the deal. Double sized tunnels need big doors, yes? I've made said doors, but they don't open all the time. How do you set up the sensors to act correctly, and how do they work? From the variables, a sensor seems to be a line (or a ray) from StartOffset to SensorRay, and if any actor of the same team intersects said line (or ray), the door is told to open. Is this true, and if so, how do you set the detection length of the sensor?

That's true.

The initial ray offset is offsetted from the same point as the sprite offset.

The EndRay offset, or whatever it is, is offsetted from the INITIAL RAY OFFSET. Thus, if you have a ray at 10,0, for example, and then set the second offset as -48,0, then the line will be 48 pixels long, and going left due to being negative.

Cool, thank you. Works fine now.