{"action":"created","issue":{"url":"https://api.github.com/repos/colah/ImplicitCAD/issues/113","repository_url":"https://api.github.com/repos/colah/ImplicitCAD","labels_url":"https://api.github.com/repos/colah/ImplicitCAD/issues/113/labels{/name}","comments_url":"https://api.github.com/repos/colah/ImplicitCAD/issues/113/comments","events_url":"https://api.github.com/repos/colah/ImplicitCAD/issues/113/events","html_url":"https://github.com/colah/ImplicitCAD/issues/113","id":38244314,"number":113,"title":"Faceting on edges of cylinders","user":{"login":"eddieparker","id":1141487,"avatar_url":"https://avatars.githubusercontent.com/u/1141487?v=3","gravatar_id":"","url":"https://api.github.com/users/eddieparker","html_url":"https://github.com/eddieparker","followers_url":"https://api.github.com/users/eddieparker/followers","following_url":"https://api.github.com/users/eddieparker/following{/other_user}","gists_url":"https://api.github.com/users/eddieparker/gists{/gist_id}","starred_url":"https://api.github.com/users/eddieparker/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/eddieparker/subscriptions","organizations_url":"https://api.github.com/users/eddieparker/orgs","repos_url":"https://api.github.com/users/eddieparker/repos","events_url":"https://api.github.com/users/eddieparker/events{/privacy}","received_events_url":"https://api.github.com/users/eddieparker/received_events","type":"User","site_admin":false},"labels":[],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":6,"created_at":"2014-07-19T20:37:20Z","updated_at":"2016-03-17T03:28:37Z","closed_at":null,"body":"I'm trying out ImplicitCAD for the first time, and noticing that the quality of the renders is less precise than OpenSCAD.  I'm not sure if I'm doing something wrong however on my side.\r\n\r\nI've attached a sample .scad file, the .stl it generates.  This is with a resolution of .125 - it's much worse if I don't set anything on the command line.\r\n![faceting](https://cloud.githubusercontent.com/assets/1141487/3635678/1467a452-0f84-11e4-9da7-2bd0b985e903.png)\r\n\r\nIs this to be expected?  OpenSCAD doesn't have the chunkiness - for comparison it renders the model like this: \r\n![openscad](https://cloud.githubusercontent.com/assets/1141487/3635682/729fb280-0f84-11e4-9a6d-f5ee194e5f54.png)\r\n\r\nscad file:\r\n\r\n\tgQuality=200;\r\n\tgMetricScrewSize=3;\r\n\tgBedHeight=4.4;\r\n\tgClipHeightAboveBed=3.25;\r\n\tgScrewWallThickness=5;\r\n\tgClipLength=12;\r\n\r\n\tscrewRadius=gMetricScrewSize/2*1.1;\r\n\touterScrewRadius=screwRadius+gScrewWallThickness/2;\r\n\ttotalHeight=gClipHeightAboveBed+gBedHeight;\r\n\r\n\tdifference()\r\n\t{\r\n\t\tunion()\r\n\t\t{\r\n\t\t\ttranslate([-outerScrewRadius,0,0])\r\n\t\t\tcube([outerScrewRadius*2,gClipLength,gClipHeightAboveBed]);\r\n\t\t\tcylinder(r=outerScrewRadius,h=totalHeight, $fn=gQuality);\r\n\t\t}\r\n\t\tcylinder(r=screwRadius,h=totalHeight, $fn=gQuality);\r\n\t}\r\n"},"comment":{"url":"https://api.github.com/repos/colah/ImplicitCAD/issues/comments/197675620","html_url":"https://github.com/colah/ImplicitCAD/issues/113#issuecomment-197675620","issue_url":"https://api.github.com/repos/colah/ImplicitCAD/issues/113","id":197675620,"user":{"login":"TLC123","id":10944617,"avatar_url":"https://avatars.githubusercontent.com/u/10944617?v=3","gravatar_id":"","url":"https://api.github.com/users/TLC123","html_url":"https://github.com/TLC123","followers_url":"https://api.github.com/users/TLC123/followers","following_url":"https://api.github.com/users/TLC123/following{/other_user}","gists_url":"https://api.github.com/users/TLC123/gists{/gist_id}","starred_url":"https://api.github.com/users/TLC123/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/TLC123/subscriptions","organizations_url":"https://api.github.com/users/TLC123/orgs","repos_url":"https://api.github.com/users/TLC123/repos","events_url":"https://api.github.com/users/TLC123/events{/privacy}","received_events_url":"https://api.github.com/users/TLC123/received_events","type":"User","site_admin":false},"created_at":"2016-03-17T03:28:37Z","updated_at":"2016-03-17T03:28:37Z","body":"The edge artifacts looks like what is expected when generating a mesh with marching cubes, more precise algorithms exist but are not implemented in ImplicitCAD. For example  [Antimonys ](https://goo.gl/fjkO6z).stl export includes feature detection to preserve corners and edges sharp.  Here's a technical paper [https://www.graphics.rwth-aachen.de/media/papers/feature1.pdf](https://www.graphics.rwth-aachen.de/media/papers/feature1.pdf)"}}