constructor(radius=1,phi=0,theta=0){this.radius=radius;this.phi=phi;// polar angle
this.theta=theta;// azimuthal angle
return this;}
Ref: https://en.wikipedia.org/wiki/Spherical_coordinate_system

phi (the polar angle) is measured from the positive y-axis. The positive y-axis is up.
theta (the azimuthal angle) is measured from the positive z-axis.