{"action":"created","comment":{"url":"https://api.github.com/repos/simbody/simbody/pulls/comments/22435733","id":22435733,"diff_hunk":"@@ -760,6 +764,44 @@ class SimTK_SIMBODY_EXPORT Visualizer::FrameController {\n     virtual ~FrameController() {}\n };\n \n+/** Causes the camera to point at and follow a point fixed on a body (a\n+ station). This might be useful if your system translates substantially\n+ and would thus leave the field of view of a stationary camera. **/\n+// This class is based on the BodyWatcher class that used to be in TimsBox.cpp.\n+class SimTK_SIMBODY_EXPORT Visualizer::BodyFollower :\n+    public Visualizer::FrameController {\n+public:\n+    /**\n+    @param[in] bodyB","path":"Simbody/Visualizer/include/simbody/internal/Visualizer.h","position":42,"original_position":42,"commit_id":"384940eee6f2f20c07051fa966a6eedb51796c74","original_commit_id":"384940eee6f2f20c07051fa966a6eedb51796c74","user":{"login":"sherm1","id":4088016,"avatar_url":"https://avatars.githubusercontent.com/u/4088016?v=3","gravatar_id":"","url":"https://api.github.com/users/sherm1","html_url":"https://github.com/sherm1","followers_url":"https://api.github.com/users/sherm1/followers","following_url":"https://api.github.com/users/sherm1/following{/other_user}","gists_url":"https://api.github.com/users/sherm1/gists{/gist_id}","starred_url":"https://api.github.com/users/sherm1/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/sherm1/subscriptions","organizations_url":"https://api.github.com/users/sherm1/orgs","repos_url":"https://api.github.com/users/sherm1/repos","events_url":"https://api.github.com/users/sherm1/events{/privacy}","received_events_url":"https://api.github.com/users/sherm1/received_events","type":"User","site_admin":false},"body":"This name doesn't match the formal parameter name in the constructor (`body`). I have been switching to `mobod` for MobilizedBodies to avoid ambiguity regarding the Body class (which I should have called something like `BodyInfo`). So I would suggest `mobodB` for this parameter name.","created_at":"2015-01-04T00:51:30Z","updated_at":"2015-01-04T00:51:30Z","html_url":"https://github.com/simbody/simbody/pull/103#discussion_r22435733","pull_request_url":"https://api.github.com/repos/simbody/simbody/pulls/103","_links":{"self":{"href":"https://api.github.com/repos/simbody/simbody/pulls/comments/22435733"},"html":{"href":"https://github.com/simbody/simbody/pull/103#discussion_r22435733"},"pull_request":{"href":"https://api.github.com/repos/simbody/simbody/pulls/103"}}},"pull_request":{"url":"https://api.github.com/repos/simbody/simbody/pulls/103","id":11386975,"html_url":"https://github.com/simbody/simbody/pull/103","diff_url":"https://github.com/simbody/simbody/pull/103.diff","patch_url":"https://github.com/simbody/simbody/pull/103.patch","issue_url":"https://api.github.com/repos/simbody/simbody/issues/103","number":103,"state":"open","locked":false,"title":"Create Visualizer::BodyFollower class.","user":{"login":"chrisdembia","id":846001,"avatar_url":"https://avatars.githubusercontent.com/u/846001?v=3","gravatar_id":"","url":"https://api.github.com/users/chrisdembia","html_url":"https://github.com/chrisdembia","followers_url":"https://api.github.com/users/chrisdembia/followers","following_url":"https://api.github.com/users/chrisdembia/following{/other_user}","gists_url":"https://api.github.com/users/chrisdembia/gists{/gist_id}","starred_url":"https://api.github.com/users/chrisdembia/starred{/owner}{/repo}","subscriptions_url":"https://api.github.com/users/chrisdembia/subscriptions","organizations_url":"https://api.github.com/users/chrisdembia/orgs","repos_url":"https://api.github.com/users/chrisdembia/repos","events_url":"https://api.github.com/users/chrisdembia/events{/privacy}","received_events_url":"https://api.github.com/users/chrisdembia/received_events","type":"User","site_admin":false},"body":"To cause the camera to follow objects around in a visualization. The class is a\r\ngeneralization of the BodyWatcher class in TimsBox.cpp. I have replaced\r\nBodyWatcher in TimsBox.cpp with this new class. I ran TimsBox before and after the change and the camera behavior looks the same to me. I've also used this BodyFollower in the rolling disc example, and it works well there too.\r\n\r\nI'm not sure where exactly I should put the new code; let me know if I should relocate the additions.\r\n\r\nSee some related discussion in #74. @sherm1 said \"Attaching the camera rigidly to moving bodies doesn't usually work well either because then the image bounces around too much.\" I didn't do anything to account for 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