Bug Beware of unusued Quality Settings / HDRP assets accounting in shader compilation and memory usage

As explained here, our team has investigated a big issue with HDRP Lit taking dozens of hours to compile and taking 1.5+gb at runtime.

We found that if you create multiple HDRP assets and assign them to quality settings, they will all count at build and run time. That is even if you only keep one quality setting enabled on your platform. HDRP Lit will always be the same size, regardless of the quality setting you choose at runtime.

That means that you cannot enable raytracing and not pay the cost of it even if disabled. You either have to endure 1.5 gb of HDRP Lit and several hours of build time to support different settings, or live with a single balanced asset and enjoy fast build and around 150mb of memory usage. That also means that if one asset is Deffered and the other is Forward, your HDRP Lit will almost double in size at runtime.

The Scalability in HDRP documentation page is therefore super wrong. The workaround is to delete all unused quality settings before building and to use only one HDRP asset per platform.

I truly hope this is a considered a bug:

• Case 1377684
• Unity 2020.3.17
• HDRP 10.6