QT 3D Surface or scatter for antenna pattern with custom gradient for spherical coordinates

[Reas]

Dear all,

I'm implementing a tool to display 3D pattern of antennas. I manage to modify the 3D surface and 3D scatter QT example to meet my needs but I miss the last requirements.

In QT I can change the color map gradient but it is dependent to one cartiesian/polar coordinate, i.e., the y-axis value, but for 3D pattern plot the color should reflect the intensity of the field, that, is the radius of the spherical plot.

To better understand QT gradient produce an image like this:

But I need to produce an image like this (without considering the lines):

There is any simple way to do it?

Best regards.