We show a method to detect accurate 3D position of people from multiple views, regardless of the geometry of the ground. In our new method we search for intersections of 3D primitives (cones) to find positions of feet. The cones are computed by back-projecting ellipses covering feet in input images. Instead of computing complex intersection body, we use approximation to speed up intersection computing. We found that feet positions are determined accurately, and the height map of the ground can be reconstructed with small error. We compared our method to other multiview-detectors - using somewhat different test methodology -, and achieved comparable results, with the benefit of handling arbitrary ground. We also present accurately reconstructed height map of non-planar ground. Our algorithm is fast and most of steps are parallelizable, making it possibly available for smart camera systems.