Re: [Plib-users] Problems using sgIsectPlanePlane(), point is always at 0, 0, 0
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From: Fay, J. F Dr C. U. A. AAC/X. <joh...@eg...> - 2011-09-20 14:53:02
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Elmi, Hello and welcome to the PLIB community. I think the problem is that you are using relative vectors when making your planes. If you say "sgMakePlane ( plane1, a1, b1, c1 )" and "sgMakePlane ( plane2, a2, b2, c2 )" you will get nonzero values for your "point". The three vectors in "sgMakePlane" are the vectors from the origin to the three points that define the plane. John F. Fay Technical Fellow, Modeling and Simulation Jacobs Technology / TEAS Group P.O. Box 1935, Eglin AFB, FL 32542-5000 850-883-3496 -----Original Message----- From: Satz Klauer [mailto:sat...@go...] Sent: Tuesday, September 20, 2011 2:16 AM To: pli...@li... Subject: [Plib-users] Problems using sgIsectPlanePlane(),point is always at 0, 0, 0 Hi, I want to find the intersection line out of two planes but fail miserably. That's what I'm doing: - I start with two triangles a1,b1,c1 and a2,b2,c2 that describe my planes and consist of three coordinates x,y and z for every corner of it - out of their corner coordinates x,y and z I calculate 3D vectors sgVec3 va1,vb1,vc1 by substracting the coordinate values b1-a1, c1-b1, a1-c1 and normalizing the result; the same is done for the second triangle's coordinates - then I call sgMakePlane (plane1,va1,vb1,vc1); sgMakePlane (plane2,va2,vb2,vc2); ret=sgIsectPlanePlane (point,dir,plane1,plane2 ); But here the result is unusable and nearly every time the same. "point" always contains _very_ small values so that after rounding to 6 decimal places the coordinates of it are 0,0,0. What am I doing wrong here? Elmi ------------------------------------------------------------------------ ------ All the data continuously generated in your IT infrastructure contains a definitive record of customers, application performance, security threats, fraudulent activity and more. Splunk takes this data and makes sense of it. Business sense. IT sense. Common sense. http://p.sf.net/sfu/splunk-d2dcopy1 _______________________________________________ plib-users mailing list pli...@li... https://lists.sourceforge.net/lists/listinfo/plib-users |