What do you think are the differences between developing a custom post-process effect in the Built-in RP, URP and HDRP?
Have you noticed any differences between creating custom post processing effects for the Post-Processing framework (Built-in RP) and the Volume framework (HDRP and URP) ?
I haven’t used HDRP’s post-processing stack, but between URP and Built-in, the easiest to make a custom effect in is the Post-Processing framework for Built-in. The documentation and examples are good and easy to find. URP is a little more confusing and difficult to wrap your head around, but it works similarly to the Built-in equivalent. Here is an article on making effects for URP’s stack. URP’s documentation is also not bad for the stack, but examples are sparse. An alternative if you want a full-screen effect is to use the FullScreenPassRenderFeature, though you won’t be able to have per-profile/per-volume control- so no volume blending.