using this another script, if I left click I can instantiate a “Joint”, and if I right-click, it instantiates it and sets its “Fixed” value to true. When I do this, the colour becomes red as expected, but the bodyType only seems to become static for one frame, before becoming dynamic (the fixed variable actually reverts to being false). Can someone please explain why this value is resetting itself?
You must find a way to get the information you need in order to reason about what the problem is.
What is often happening in these cases is one of the following:
the code you think is executing is not actually executing at all
the code is executing far EARLIER or LATER than you think
the code is executing far LESS OFTEN than you think
the code is executing far MORE OFTEN than you think
the code is executing on another GameObject than you think it is
To help gain more insight into your problem, I recommend liberally sprinkling Debug.Log() statements through your code to display information in realtime.
Doing this should help you answer these types of questions:
is this code even running? which parts are running? how often does it run? what order does it run in?
what are the values of the variables involved? Are they initialized? Are the values reasonable?
are you meeting ALL the requirements to receive callbacks such as triggers / colliders (review the documentation)
Knowing this information will help you reason about the behavior you are seeing.
You can also put in Debug.Break() to pause the Editor when certain interesting pieces of code run, and then study the scene
You could also just display various important quantities in UI Text elements to watch them change as you play the game.
If you are running a mobile device you can also view the console output. Google for how on your particular mobile target.
Here’s an example of putting in a laser-focused Debug.Log() and how that can save you a TON of time wallowing around speculating what might be going wrong: