Surface graphics for extrusion additive manufacturing

In an extrusion deposition modeling process for constructing a solid object by depositing successive layers of material upon a build plate, performed by a system comprising at least one extrusion nozzle for extruding the material and a plurality of motors for creating relative motion between the extrusion nozzle and the build plate, a method comprising the steps of:

• obtaining, as a first data set, motion instructions, calculated from shape data about the object and comprising, for at least one layer to be deposited, one or more perimeter toolpaths paralleling an outer contour according to the shape information, the perimeter toolpaths comprising an ordered set of waypoints, and segments defined therebetween, arranged for moving an extrusion nozzle to deposit material in compliance with the shape information for the object;
• obtaining a second data set describing a graphical pattern of data values as a function of at least two dimensions;
• establishing a unique positional value for at least two points that lie along at least one perimeter toolpath;
• establishing a monotonic mathematical relationship between a spatial range of positional values of points that lie along the first perimeter toolpath and a graphical range of values of a coordinate along at least one dimension of the graphical pattern;
• determining, within the graphical range of values, at least one first graphical pattern transition location as a coordinate value at which data values transition from a first state to a second state and at least one second graphical pattern transition location as a coordinate value at which data values transition from the second state to the first state, the first and second graphical pattern transition locations defining the endpoints of a graphically-defined interval of coordinate values over which the graphical pattern data values correspond to the second state;
• applying the monotonic mathematical relationship to determine a toolpath diversion range as a range of positional values along the spatial range that correspond to the graphically defined interval within the graphical range;
• assembling a finalized toolpath that comprises a plurality of points that lie along the first perimeter toolpath and have positional values outside of the toolpath diversion range, and, for positional values that fall within the toolpath diversion range, comprises at least one alternative waypoint that does not lie along the first perimeter toolpath;
• and
• outputting a third data set comprising motion instructions for building the object according to the shape information in the first data set and including the finalized toolpath.