Method for automated treating of 3D surfaces

A method of automatically treating a surface of a 3D object, comprising the steps of:

• a) obtaining or producing a digital 3D shape representation that defines characteristics of the 3D object;
• b) using a computerized device to convert the 3D shape representation into a digital 2D shape representation that defines the surface of the 3D object as it would be if laid out flat;
• c) using the computerized device to generate a digital 2D tool path representation defining movements that an applicator or removal tool would have to take to treat a surface of the shape defined by the 2D shape representation;
• d) using the computerized device to convert the 2D tool path representation to a digital 3D tool path representation defining movements that the applicator or removal tool will take to deposit material on, or remove it from, the surface to treat the 3D object;
• and
• e) using the 3D tool path representation to control the applicator tool or removal tool to move according to the 3D tool path to treat the 3D object;
• wherein the computerized device further:
• i) defines the 3D representation in terms of a notional 3D mesh;
• ii) applies an unwrapping transform to notionally situate an element of the 3D mesh in 2D space to notionally identify a 2D sub-surface, and registers the transform against that element;
• iii) identifiers a notional mesh element adjacent to the element in step ii);
• iv) repeats steps ii and iii) until there are no further adjacent notional mesh elements available, whereby each next notional mesh element is selected on a weighting based on largest size and lowest angular misalignment with a previous notional mesh element;
• v) identifies another untransformed mesh element in the 3D mesh;
• vi) repeats steps ii) through v) until there are no untransformed mesh elements in the 3D mesh;
• vii) generates a toolpath suitable to treat a notional 2D surface, such surface comprising a collection of the 2D sub-surfaces, and registers each 2D subsurface with a respective segment of the tool path;
• and
• viii) applies an inverse of the unwrapping transforms registered in step ii) to each of the tool path segments.