{"action":"created","issue":{"url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1975","repository_url":"https://api.github.com/repos/RobotLocomotion/drake","labels_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1975/labels{/name}","comments_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1975/comments","events_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1975/events","html_url":"https://github.com/RobotLocomotion/drake/pull/1975","id":144980202,"number":1975,"title":"BUG_FIX: Implements fixes on the collision coordinate transformation used to compute collision forces","user":{"login":"amcastro-tri","id":17601461,"avatar_url":"https://avatars.githubusercontent.com/u/17601461?v=3","gravatar_id":"","url":"https://api.github.com/users/amcastro-tri","html_url":"https://github.com/amcastro-tri","followers_url":"https://api.github.com/users/amcastro-tri/followers","following_url":"https://api.github.com/users/amcastro-tri/following{/other_user}","gists_url":"https://api.github.com/users/amcastro-tri/gists{/gist_id}","starred_url":"https://api.github.com/users/amcastro-tri/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/amcastro-tri/subscriptions","organizations_url":"https://api.github.com/users/amcastro-tri/orgs","repos_url":"https://api.github.com/users/amcastro-tri/repos","events_url":"https://api.github.com/users/amcastro-tri/events{/privacy}","received_events_url":"https://api.github.com/users/amcastro-tri/received_events","type":"User","site_admin":false},"labels":[{"url":"https://api.github.com/repos/RobotLocomotion/drake/labels/waiting%20for%20code%20update","name":"waiting for code update","color":"eb6420"}],"state":"open","locked":false,"assignee":null,"milestone":null,"comments":15,"created_at":"2016-03-31T18:25:50Z","updated_at":"2016-04-05T02:00:46Z","closed_at":null,"pull_request":{"url":"https://api.github.com/repos/RobotLocomotion/drake/pulls/1975","html_url":"https://github.com/RobotLocomotion/drake/pull/1975","diff_url":"https://github.com/RobotLocomotion/drake/pull/1975.diff","patch_url":"https://github.com/RobotLocomotion/drake/pull/1975.patch"},"body":"This fixes #1940. \r\n\r\nThe fix is within RigidBodySystem::dynamics where the transformation `R` that transforms from the world frame into the collision point frame was incorrectly computed:\r\n\r\n1. The transformation `R` was not a rotation but a rotation plus a reflection. The problem was on the computation of tangent2 which resulted on a frame which was not right handed.\r\n2. The transformation matrix `R` that transforms from the world frame to the collision point frame was implemented as the transpose of what it actually should be. Therefore the inverse of the transformation was implemented instead."},"comment":{"url":"https://api.github.com/repos/RobotLocomotion/drake/issues/comments/205597933","html_url":"https://github.com/RobotLocomotion/drake/pull/1975#issuecomment-205597933","issue_url":"https://api.github.com/repos/RobotLocomotion/drake/issues/1975","id":205597933,"user":{"login":"RussTedrake","id":6442292,"avatar_url":"https://avatars.githubusercontent.com/u/6442292?v=3","gravatar_id":"","url":"https://api.github.com/users/RussTedrake","html_url":"https://github.com/RussTedrake","followers_url":"https://api.github.com/users/RussTedrake/followers","following_url":"https://api.github.com/users/RussTedrake/following{/other_user}","gists_url":"https://api.github.com/users/RussTedrake/gists{/gist_id}","starred_url":"https://api.github.com/users/RussTedrake/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/RussTedrake/subscriptions","organizations_url":"https://api.github.com/users/RussTedrake/orgs","repos_url":"https://api.github.com/users/RussTedrake/repos","events_url":"https://api.github.com/users/RussTedrake/events{/privacy}","received_events_url":"https://api.github.com/users/RussTedrake/received_events","type":"User","site_admin":false},"created_at":"2016-04-05T02:00:46Z","updated_at":"2016-04-05T02:00:46Z","body":"@jamiesnape -- why did the win64 report failure?"}}