  The use of 3D Gaussians as representation of radiance fields has enabled high
quality novel view synthesis at real-time rendering speed. However, the choice
of optimising the outgoing radiance of each Gaussian independently as spherical
harmonics results in unsatisfactory view dependent effects. In response to
these limitations, our work, Factorised Tensorial Illumination for 3D Gaussian
Splatting, or 3iGS, improves upon 3D Gaussian Splatting (3DGS) rendering
quality. Instead of optimising a single outgoing radiance parameter, 3iGS
enhances 3DGS view-dependent effects by expressing the outgoing radiance as a
function of a local illumination field and Bidirectional Reflectance
Distribution Function (BRDF) features. We optimise a continuous incident
illumination field through a Tensorial Factorisation representation, while
separately fine-tuning the BRDF features of each 3D Gaussian relative to this
illumination field. Our methodology significantly enhances the rendering
quality of specular view-dependent effects of 3DGS, while maintaining rapid
training and rendering speeds.
