3D design of B-rep skin

A non-transitory data storage medium having recorded thereon a computer program comprising instructions for performing a method for designing a 3D modeled object that represents a mechanical part, the method comprising:

• obtaining, at a CAD system, a B-Rep skin that represents the mechanical part, the B-rep skin having a B-rep portion including:
• a boundary face bounded by one or more boundary edges of the B-rep skin, a boundary edge bounding a respective boundary face being an edge which is not shared with a face other than the respective boundary face and thereby bounds only one face of the one or more boundary edges bounding the boundary face, and
• one or more first faces each adjacent to the boundary face at a respective internal edge of the B-rep skin;
• defining, by graphical user-interaction with the CAD system, a surface;
• constructing, automatically by the CAD system, a B-rep replacement, the constructing including:
• creating one or more second faces each adjacent to the boundary face and bounded by a respective boundary edge of the B-rep skin;
• generating a B-rep assembly which includes:
• one or more third faces each coincident with the surface, each third face having one or more edges, each edge of each third face being internal to the B-rep assembly and lying on the surface,
• one or more fourth faces each coincident with a first face of the one or more first faces and adjacent to a third face of the one or more third faces, each fourth face having two or more edges, at least two edges of each fourth face geometrically lying on a supporting surface of the respective first face with which the fourth face coincides, and
• one or more fifth faces each coincident with a second face of the one or more second faces and adjacent to a third face of the one or more third faces, each fifth face having two or more edges, at least two edges of each fifth face geometrically lying on a supporting surface of the respective second face with which the fifth face coincides;
• and
• removing from the B-rep assembly each fifth face;
• and
• replacing, in the B-Rep skin, the B-rep portion by the constructed B-rep replacement.

A system comprising:

• a hardware processor coupled to a hardware memory,
• wherein the hardware memory has recorded thereon a computer program including instructions for designing a 3D modeled object that represents a mechanical part that when executed by the hardware processor causes the hardware processor to be configured to
• obtain, at a CAD system, a B-Rep skin that represents the mechanical part, the B-rep skin having a B-rep portion including:
• a boundary face bounded by one or more boundary edges of the B-rep skin, a boundary edge bounding a respective boundary face being an edge which is not shared with a face other than the respective boundary face and thereby bounds only one face of the B-rep skin, and
• one or more first faces each adjacent to the boundary face at a respective internal edge of the B-rep skin;
• define, by graphical user-interaction with the CAD system, a surface;
• construct, automatically by the CAD system, a B-rep replacement, the constructing including:
• creating one or more second faces each adjacent to the boundary face and bounded by a respective boundary edge of the one or more boundary edges bounding the boundary face,
• generating a B-rep assembly which includes:
• one or more third faces each coincident with the surface, each third face having one or more edges, each edge of each third face being internal to the B-rep assembly and lying on the surface,
• one or more fourth faces each coincident with a first face of the one or more first faces and adjacent to a third face of the one or more third faces, each fourth face having two or more edges, at least two edges of each fourth face geometrically lying on a supporting surface of the respective first face with which the fourth face coincides, and
• one or more fifth faces each coincident with a second face of the one or more second faces and adjacent to a third face of the one or more third faces, each fifth face having two or more edges, at least two edges of each fifth face geometrically lying on a supporting surface of the respective second face with which the fifth face coincides, and
• removing from the B-rep assembly each fifth face;
• and
• replace, in the B-Rep skin, the B-rep portion by the constructed B-rep replacement.