as my knowledge, the x axis is from left to right (→), y is bottom to top (↑), z is inside to outside of the screen (·).
In Spherical, phi is start from the +y (↑), and stand for vertical angle. But the SphereGeometry is from the -x (←), and stand for horizontal angle.
Incidentally the horizontal angle theta in Spherical is start from +z (·), not -x (←).
It caused trouble for my calculations, and I want to know why.
In Spherical
phi– polar angle in radians from the y (up) axis. Default is0.theta– equator angle in radians around the y (up) axis. Default is0.In SphereGeometry
phiStart— specify horizontal starting angle. Default is0.phiLength— specify horizontal sweep angle size. Default is Math.PI * 2.thetaStart— specify vertical starting angle. Default is0.thetaLength— specify vertical sweep angle size. Default isMath.PI.
Example when i set SphereGeometry.phiStart = PI/2, in Spherical‘s system, the horizontal angle PI/2 (90deg) means rightside (+x), but actually its start from frontside (+z)!
picture of the example
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