Implementing the Multiscattering sky texture

I’m not a computer scientist, but enjoy new tech, and if I feel some nice tools are missing in open-source projects then I can’t stop thinking about implementing them. Today my Pull Request for the Multiple Scattering Sky Texture has finally been merged into the main Blender 5.0 branch!

Old

I’ve already implemented an improved Nishita Sky Texture back in 2020, but that sky model was lacking an important feature, multiple bounces of light.
Light in the real world bounces off many times before hitting the camera, there was need for a multiple scattering system.

New

The new Multiple Scattering system is based on this amazing work by Fernando García Liñán. It works by calculating the bounces of the Sun light through the Earth’s atmosphere using 4 wavelengths, and then converting the spectrum to the XYZ color representation using an ad-hoc matrix conversion.

Having a system that takes multiple bounces into account gives more accurate sky color results compared to single scattering. This is because light bouncing multiple times in the atmosphere particles such as air molecules, aerosols and ozone particles rather than only once will yeld more accurate results to the ground truth.

Huge thanks to Fernando for his awesome work!

Helps

As it happened in 2020 when implementing the Single Scattering sky texture, developers helped me get this project merged into main, as well as Fernarno himself helped me get through the implementation! 😃

I love the Blender community!