Tool path data generation in additive manufacturing

A data processing system for generating tool path data for use in additive manufacturing, the system comprising processing circuitry configured to perform a method of generating tool path data to be followed by an additive manufacturing apparatus when manufacturing a physical object, the processing circuitry being configured to:

• provide object design data in which a structural feature forming part of the physical object is represented by generating a parametric representation of the structural feature in the form of a line or surface, wherein the line or surface does not ever form part of a volumetric representation which encloses a volume of the physical object;
• then slice a section of the line or surface using an intermediate slicing layer that is provided between first and second physical build layers of the additive manufacturing apparatus, wherein slicing the section of the line or surface generates an intermediate layer point or line at an intersection of the section of the line or surface and the intermediate slicing layer, wherein the intermediate layer point or line is located between the first and second physical build layers;
• project the intermediate layer point or line to a projected build layer point or line that lies within a physical build layer of the additive manufacturing apparatus;
• and
• use the projected build layer point or line to provide tool path data for that physical build layer.

A non transitory computer readable medium comprising computer software code which when used to operate a data processing system comprising one or more data processors causes, in conjunction with said one or more data processors, said system to carry out a method of generating tool path data to be followed by an additive manufacturing apparatus when manufacturing a physical object, the method comprising:

• providing object design data in which a structural feature forming part of the physical object is represented by generating a parametric representation of the structural feature in the form of a line or surface, wherein the line or surface does not ever form part of a volumetric representation which encloses a volume of the physical object;
• then slicing a section of the line or surface using an intermediate slicing layer that is provided between first and second physical build layers of the additive manufacturing apparatus, wherein slicing the section of the line or surface generates an intermediate layer point or line at an intersection of the section of the line or surface and the intermediate slicing layer, wherein the intermediate layer point or line is located between the first and second physical build layers;
• projecting the intermediate layer point or line to a projected build layer point or line that lies within a physical build layer of the additive manufacturing apparatus;
• and
• using the projected build layer point or line to provide tool path data for that physical build layer.