Detecting cut-outs

A non-transitory computer readable storage medium having recorded thereon a computer program comprising instructions for performing a computer-implemented method for determining specifications of the input of a manufacturing operation that outputs a part having cut-outs, the manufacturing operation consisting in forming the cut-outs via stamping, machining, milling and/or laser cutting, the method comprising:

• providing specifications of the output part, including a user-designed B-Rep having cycles of edges and modeling the part, the cut-outs being represented by the user with tunnels in the B-Rep;
• determining, from equivalence classes of non-boundary cycles of the B-Rep with respect to the cycle-homology relationship, the set that consists of all cycles being the one having the smallest length in a respective equivalence class;
• performing a process on the set that includes iterating:
• replacing a cycle of the set by its /2 sum with an adjacent boundary cycle when this reduces the length, and
• for a cycle of the set and its /2 sum with a shorter cycle of the set, deleting the cycle when the sum results in a boundary cycle, otherwise replacing the cycle by the sum when this reduces the length;
• then, identifying among the cycles of the set a number n of cycles as location of tunnels, wherein n is the genus of the B-Rep;
• and then
• editing the B-Rep by removing identified tunnels and filling the empty space and outputting the specifications of the output part with the edited B-Rep.

A system comprising:

• a processor coupled to a memory and a graphical user interface, the memory having recorded thereon a computer program comprising instructions for performing a computer-implemented determining of specifications of the input of a manufacturing operation that outputs a part having cut-outs, the manufacturing operation consisting in forming the cut-outs via stamping, machining, milling and/or laser cutting,
• wherein the processor is configured by the computer program to:
• provide specifications of the output part, including a user-designed B-Rep having cycles of edges and modeling the part, the cut-outs being represented by the user with tunnels in the B-Rep,
• determine, from equivalence classes of non-boundary cycles of the B-Rep with respect to the cycle-homology relationship, the set that consists of all cycles being the one having the smallest length in a respective equivalence class,
• perform a process on the set that includes iterating:
• replacing a cycle of the set by its /2 sum with an adjacent boundary cycle when this reduces the length,
• for a cycle of the set and its /2 sum with a shorter cycle of the set, deleting the cycle when the sum results in a boundary cycle, otherwise replacing the cycle by the sum when this reduces the length,
• then, identify among the cycles of the set a number n of cycles as location of tunnels, wherein n is the genus of the B-Rep, and then
• edit the B-Rep by removing identified tunnels and filling the empty space and output the specifications of the output part with the edited B-Rep.