I'll probably make the field edges visible in 2.43w. They will only be visible in non torridal sims, making them visible will be optional and controlable via a human setting, if they are visible, .reftype will be 2 when the closest thing in the focus eye is a world edge.
Note that a forthcoming enhancement is for the refpos sysvars to reflect the actual positon of the portion of the viewed object, be it a shape or the world edge, rather than the viewed object's orgin (for shapes, the upper left corner). This way, bots can remember where the corners of shapes are for example or in the future, where their burrow is.
