In 3DGS, spherical harmonics are used to model view-dependent changes in color. https://en.m.wikipedia.org/wiki/Spherical_harmonics https://en.m.wikipedia.org/

In 3DGS, spherical harmonics are used to model view-dependent changes in color. https://en.m.wikipedia.org/wiki/Spherical_harmonics https://en.m.wikipedia.org/wiki/Spherical_harmonics Basically for each Gaussian there is a set of coefficients and those are used to calculate what color should be rendered depending on the viewing angle of the camera. And the SH coeffs are optimized through gradient descent just like the other parameters including position and shape.