Dear Eric,
Thanks for the response. I tried it this way but the two drawings are consistent with each other. Consider a line between points spherical points (30, 0, 0) and (30, 0, Pi). If we convert it to cartesian system, it is a line between (0, 0, 30) and (0, 0, -30) and hence should pass through origin along Z axis. Though when I tried it your way, it is not passing through the center of sphere, which is at origin. Please see the attached file.
Thanks once again S G
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