Freeware for graphing (3D) spherical coordinates?

[cj]

Do you know of any freeware available for graphing (3D) spherical coordinates -- like Maple (only freeware)?

[pnaj]

Scilab is an open-source clone of Matlab ... doesn't have all the features ... but does have all the same sort of plots as Matlab.

Just type scilab into Google to get to their homepage.