Conversion of geometry to boundary representation with facilitated editing for computer aided design and 2.5-axis subtractive manufacturing

A non-transitory computer-readable medium encoding a computer aided design program operable to cause one or more data processing apparatus to perform operations comprising:

• obtaining a first model of an object to be manufactured using a 2.5-axis subtractive manufacturing process, wherein the first model comprises smooth curves fit to contours representing discrete height layers of the object to be manufactured using the 2.5-axis subtractive manufacturing process;
• modifying at least one of the smooth curves to facilitate the 2.5-axis subtractive manufacturing process, wherein the modifying comprises
• detecting at least a portion of a first smooth curve for a first of the discrete height layers that is almost coincident with at least a portion of a second smooth curve for a second of the discrete height layers, and
• replacing the at least a portion of the first smooth curve for the first of the discrete height layers with the at least a portion of the second smooth curve for the second of the discrete height layers;
• preparing an editable model of the object, the editable model comprising a series of construction steps represented in a parametric feature history, wherein the series of construction steps includes combining extruded versions of the smooth curves to form a solid three dimensional (3D) model of the object in a boundary representation format, and the parametric feature history includes a sketch feature associated with at least one of the discrete height layers;
• rendering a user interface element showing the sketch feature in relation to the editable model;
• receiving user input via the user interface element;
• and
• reshaping, responsive to the user input, a subset of the smooth curves in the at least one of the discrete height layers to change the solid 3D model;
• and
• replaying the series of construction steps represented in the parametric feature history to construct the solid 3D model of the object in the boundary representation format, as changed by the user input.

A system comprising:

• a display device;
• one or more data processing apparatus coupled with the display device;
• and
• a non-transitory storage medium coupled with the one or more data processing apparatus, the non-transitory storage medium encoding:
• program code that causes the one or more data processing apparatus to obtain a first model of an object to be manufactured using a 2.5-axis subtractive manufacturing process, wherein the first model comprises smooth curves fit to contours representing discrete height layers of the object to be manufactured using the 2.5-axis subtractive manufacturing process;
• program code that causes the one or more data processing apparatus to modify at least one of the smooth curves to facilitate the 2.5-axis subtractive manufacturing process, including program code to detect at least a portion of a first smooth curve for a first of the discrete height layers that is almost coincident with at least a portion of a second smooth curve for a second of the discrete height layers, and program code to replace the at least a portion of the first smooth curve for the first of the discrete height layers with the at least a portion of the second smooth curve for the second of the discrete height layers;
• program code that causes the one or more data processing apparatus to prepare an editable model of the object, the editable model comprising a series of construction steps represented in a parametric feature history, wherein the series of construction steps includes combining extruded versions of the smooth curves to form a solid three dimensional (3D) model of the object in a boundary representation format, and the parametric feature history includes a sketch feature associated with at least one of the discrete height layers;
• program code that causes the one or more data processing apparatus to render to the display screen a user interface element showing the sketch feature in relation to the editable model;
• program code that causes the one or more data processing apparatus to receive user input via the user interface element;
• program code that causes the one or more data processing apparatus to reshape, responsive to the user input, a subset of the smooth curves in the at least one of the discrete height layers to change the solid 3D model;
• and
• program code that causes the one or more data processing apparatus to replay the series of construction steps represented in the parametric feature history to construct the solid 3D model of the object in the boundary representation format, as changed by the user input.