Path: news.mathworks.com!not-for-mail From: <HIDDEN> Newsgroups: comp.soft-sys.matlab Subject: Re: Find the correspondent coordinates of a unit sphere in a sphere of radius X Date: Sun, 2 Dec 2012 18:14:08 +0000 (UTC) Organization: The MathWorks, Inc. Lines: 10 Message-ID: <k9g5pg$g8d$1@newscl01ah.mathworks.com> References: <k9fj58$j44$1@newscl01ah.mathworks.com> Reply-To: <HIDDEN> NNTP-Posting-Host: www-04-blr.mathworks.com Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit X-Trace: newscl01ah.mathworks.com 1354472048 16653 172.30.248.35 (2 Dec 2012 18:14:08 GMT) X-Complaints-To: news@mathworks.com NNTP-Posting-Date: Sun, 2 Dec 2012 18:14:08 +0000 (UTC) X-Newsreader: MATLAB Central Newsreader 1187260 Xref: news.mathworks.com comp.soft-sys.matlab:783981 "Javier " <javsanzperez@gmail.com> wrote in message <k9fj58$j44$1@newscl01ah.mathworks.com>... > ..... find the correspondent coordinates of a unit sphere in a sphere of radius X. ...... - - - - - - - - - - Let P1 = (x1;y1;z1] be the coordinates of some point on a sphere of radius R1 with center located at C1 = [u1;v1;w1] and let P2 = [x2;y2;z2] be the coordinates of the corresponding point on a sphere of radius R2 with center at C2 = [u2;v2;w2]. Then P2 can be expressed in terms of P1 by the vector equation: P2 = C2 + (R2/R1)*(P1-C1); This amounts to a translation from center C1 to center C2 followed by an expansion by the ratio R2/R1, and, as you see, it is a linear expression. Roger Stafford