{"id":796,"date":"2006-12-11T20:00:50","date_gmt":"2006-12-11T18:00:50","guid":{"rendered":"http:\/\/www.randform.org\/blog\/?p=796"},"modified":"2006-12-11T20:00:50","modified_gmt":"2006-12-11T18:00:50","slug":"confocal-quadrics","status":"publish","type":"post","link":"https:\/\/www.randform.org\/blog\/?p=796","title":{"rendered":"confocal quadrics"},"content":{"rendered":"<div align=\"center\"><img id=\"image794\" src=\"http:\/\/www.randform.org\/blog\/wp-content\/2006\/12\/confocal.png\" alt=\"confocal.png\" \/><\/div>\n<p>Confocal <a href=\"http:\/\/en.wikipedia.org\/wiki\/Quadric\">quadrics<\/a> are known to form a triply orthogonal coordinate system on most of the three dimesional space. <!--more--><\/p>\n<p><\/p>\n<p>This means there are three one parameter families of surfaces (in this case they are ellipsoids, hyperboloids of one sheet, and hyperboloids of two sheets) such that through every point there goes exactly one surface of each family and the surfaces intersect orthogonaly. Since this is sometimes difficult to imagine I made <a href=\"http:\/\/www3.math.tu-berlin.de\/~hoffmann\/interactive\/confocal\/confocal.jnlp\">a webstart<\/a> for it. The surfaces are cut in half so that one can better see what is happening, and in case of the hyperboloids they are cropped of course (these surfaces are unbounded). Three sliders let you browse through the three families.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Confocal quadrics are known to form a triply orthogonal coordinate system on most of the three dimesional space.<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":[],"categories":[2,14],"tags":[],"_links":{"self":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/796"}],"collection":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=796"}],"version-history":[{"count":0,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=\/wp\/v2\/posts\/796\/revisions"}],"wp:attachment":[{"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=796"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=796"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.randform.org\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=796"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}