ID:2049126
 
(See the best response by Lummox JR.)
Problem description:

Anyone have any tips on how to implement a working circular collision model for pixel movement?
There's a list variable 'bounds' that has little documentation on it, but I believe it'd be the best way to do what you're looking for.

Essentially you'd figure out how to create a "circle" shape with varying bound sets.

obj/circle
bounds = list("1,2 to 4,4","2,1 to 3,5")

I'm not 100% certain if that's the way the bounds list works, but I imagine so.
Best response
atom.bounds is not a list. It's a string, always.

At this time, BYOND doesn't support circular bounding boxes. The bounds var was implemented as a string, however, in the hopes that at some point in the future that might be feasible.