The dynamic non interference judgement problem refers to the judgement on non interference between two geometric figures in relative motion at any instance which often occurs in layout optimization

route programming for robots

dynamic simulation

etc.It is of great computational complexity and is to be further discussed.This paper mainly deals with the case of two rectangles.According to the theory of the No Fit Polygon and rectangle's geometric feature

the authors give the rules of the judgment

the proof of the rules

and the simple formulas to compute the apex of the No Fit Polygon(transformed into symmetrical octagon).As a result

the non interference algorithm of above two dimensional geometric figures is established.This algorithm is simple and efficient.In particular

it is suitable for the judgment on non interference between two rectangles in relative motion at any instance

so it is of the certain value of application.