The manufacture of parametrically defined B-spline and other types of surfaces suffers from a number of drawbacks because the tool-positioning methods used do not have interference-checking capabilities and the machine controller lacks the computing power to do tool positioning in real time. If the tool-positioning method does not perform interference checking, the tool will undercut certain portions of the surface. Because of the lack of computing power, the tool-positioning algorithm is performed off line, creating large data-location files that must be downloaded to the machine controller; this downloading process is prone to transmission errors and data starvation [1]. To address these problems, a new controller is presented that implements a tool-positioning algorithm as a set of parallel processes that are executed in real time on a network of transputers. Tasks that can be performed in parallel are identified by a careful examination of the tool-positioning algorithm. An example surface is manufacturel to demonstrate the gouge-free surface-machining ability of the controller.