- You can use a Cull Distance Volyme to affect a bunch of objects without messing with materials. But the transition won’t be faded. You’d need a masked material with dither temporal AA to achieve that, no matter what, I’m afraid.
More things to search are: Dithered LOD transition. Per instance cull fade.
- Are you sure the scene doesn’t use a master material you can tweak? look into it.
Maybe you can fake something with a post process? Doesn’t sound like you’re making a realtime critical scene.