BBS: Inland Empire Archive Date: 05-09-92 (10:47) Number: 68 From: PAUL LEONARD Refer#: NONE To: RICH GELDREICH Recvd: NO Subj: 3-d Conf: (2) Quik_Bas

On or about <May 06 23:21>, Ron Mcdermott (1:272/26) scribbled: RG>Do you think a book on Analytical Geometry[think that's how RG>you spell it] would help out? Yes, it would (and yes, that's how it's spelled, although it's usually called "analytic geometry"). As someone else posted, you need at least three equations to solve for three unknowns and he gave the suggestion of using the dot product of two vectors. There are several other equations yuo can use as well. One is that the distance between a point P0(x0,y0,z0) and the plane ax+by+cz+d=0 is given by: |ax0 + by0 + cz0 + d| D = ======================= SQRT(a^2 + b^2 + c^2) You already know D and you can find the equation of the plane if you have three points in the plane that are not all on the same line (3 of the corners you defined will do), so this will give you one more equation of x0,y0,z0 to work with. My assumption is that the point in question is either a light source or the viewpoint to a 3-d surface and that you intend to rotate the surface about this point (or something to that effect). An understanding of vectors in 3-space and 3-D surfaces & curves would be very useful in applications like this, so i'd suggest you look around for a college textbook - most first- & second-year calculus textbooks cover these topics. You might also look around for a book on linear algebra, which covers matrices and their manipulation (which is how vector products are calculated). ptl --- msged 2.07 * Origin: PTL Pointwork (1:105/48.111)

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