René's URL Explorer Experiment

{"@context":"https://schema.org","@type":"DiscussionForumPosting","headline":"Unexpected behavior with hole and hull?","articleBody":"Hello,\r\n\r\nI'm not sure whether the behavior is expected or not. But for me it was a bit of a surprise: If I do a hull on two objects with holes, the result is a hull of the object minus a hull of the holes. To make it more clear: Here is an example:\r\n\r\n````\r\n#!/usr/bin/env python3\r\n\r\nfrom solid import *\r\nfrom solid.utils import *\r\n\r\nc = cylinder(r=10) - hole()(cylinder(r=5))\r\nx = hull()(c, left(10)(c))\r\nprint(scad_render(x))\r\n````\r\n\r\nThis generates one long hole:\r\n````\r\ndifference(){\r\n        hull() {\r\n                difference() {\r\n                        cylinder(r = 10);\r\n                }\r\n                translate(v = [-10, 0, 0]) {\r\n                        difference() {\r\n                                cylinder(r = 10);\r\n                        }\r\n                }\r\n        }\r\n        /* Holes Below*/\r\n        hull(){\r\n                union(){\r\n                        cylinder(r = 5);\r\n                }\r\n                translate(v = [-10, 0, 0]){\r\n                        union(){\r\n                                cylinder(r = 5);\r\n                        }\r\n                }\r\n        } /* End Holes */ \r\n}\r\n````\r\n![Screenshot](https://gist.githubusercontent.com/c-mauderer/37902765312ec79034bedbbeba08c742/raw/c7da67d50e163da1d1ec78e113478791ad1cd537/Screenshot_20211127_123133.png)\r\n\r\nI would have expected two round holes:\r\n````\r\n\r\ndifference(){\r\n        hull() {\r\n                difference() {\r\n                        cylinder(r = 10);\r\n                }\r\n                translate(v = [-10, 0, 0]) {\r\n                        difference() {\r\n                                cylinder(r = 10);\r\n                        }\r\n                }\r\n        }\r\n        /* Holes Below*/\r\n        union(){\r\n                cylinder(r = 5);\r\n        }\r\n        translate(v = [-10, 0, 0]){\r\n                union(){\r\n                        cylinder(r = 5);\r\n                }\r\n        } /* End Holes */ \r\n}\r\n````\r\n![Screenshot](https://gist.githubusercontent.com/c-mauderer/37902765312ec79034bedbbeba08c742/raw/c7da67d50e163da1d1ec78e113478791ad1cd537/Screenshot_20211127_123240.png)\r\n\r\nIs that expected behavior?","author":{"url":"https://github.com/c-mauderer","@type":"Person","name":"c-mauderer"},"datePublished":"2021-11-27T18:57:45.000Z","interactionStatistic":{"@type":"InteractionCounter","interactionType":"https://schema.org/CommentAction","userInteractionCount":14},"url":"https://github.com/190/SolidPython/issues/190"}