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 Author Comment/Response phd student 04/29/13 01:55am I am a phd student, I work on quadric surfaces. I have an ellipsoid such that: a = 20.; b = 60.; c = 20.; x0 = 0.; y0 = 0.; z0 = 0.; eq = (x + x0)^2/a^2 + (y - y0)^2/b^2 + (z - z0)^2/c^2 - 1; QH = {{1/a^2, 0, 0, -(x0/a^2)}, {0, 1/b^2, 0, -(y0/b^2)}, {0, 0, 1/ c^2, -(z0/c^2)}, {0, 0, 0, -1 + x0^2/a^2 + y0^2/b^2 + z0^2/c^2}}; I need to project it by the camera Matcam = {{39.1596, -203.069, 526.526, 196977.}, {-75.0686, -410.767, 75.0686, 147733.}, {-0.609208, -0.507673, 0.609208, 492.443}}; The result is a conic, it is an ellipse. I project Qs by applying this formula: m = {{1, 0, 0, 0}, {0, 1, 0, 0}, {0, 0, 1, 0}}; H = PseudoInverse[Matcam].m; m // MatrixForm H // MatrixForm conic = Transpose[H].QH.H; conic // MatrixForm coniq = conic[[{1, 2, 4}, {1, 2, 4}]]; coniq // MatrixForm my conic result is conic, I plot it using contour plot like this: ContourPlot[{x, y, 1}.coniq.{x, y, 1} == 0, {x, -20, 20}, {y, -20, 20}] but it does not give any graphics. Please help me? may the formula of projection is false? URL: ,

 Subject (listing for 'project ellipsoid on 2D') Author Date Posted project ellipsoid on 2D phd student 04/29/13 01:55am Re: project ellipsoid on 2D Bill Simpson 04/30/13 00:42am Re: Re: project ellipsoid on 2D phd student 04/30/13 11:01am Re: Re: Re: project ellipsoid on 2D Bill Simpson 05/02/13 08:30am
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