In the far field calculation, complex electric and magnetic fields are calculated on the far field sphere, where the radius of the sphere is large enough to be well inside the Fraunhofer (far-field) region, as described in the technical reference. The following image shows a mesh annotation for the typical far field sphere. Far field results are calculated at every node on this sphere.
The same far field sphere is used for every far field calculation in a given simulation. You can change the sampling increments in the simulation setup dialog box by adjusting the values in Antenna Far Fields > Sphere Sampling Increment, Theta and Antenna Far Fields > Sphere Sampling Increment, Phi. Regardless of the increment values, the most tightly-spaced sampling takes place at the north and south poles. If you expect high radiation or a complex lobe pattern in a particular direction and you wish to increase the far field sampling at that location without raising the sampling density all over the sphere, you can rotate the positions of these dense regions by changing the Antenna Far Fields > Sphere X Axis and Antenna Far Fields > Sphere Z Axis in the simulation setup dialog box.
In addition to the spherical mesh, RF3p also outputs a far field mesh for every 3D antenna pattern, where these meshes are shaped according to the power flux density at each node.