Can anyone think of a way to simulate the Invisibility effect archetype without actually applying the invisibility shader? I'm working on a spell that surrounds the caster with mist and makes him undetectable visually, but the invisibility shader kind of spoils the effect I'm going for. Any way to fake it, or prevent the archetype from applying it?

I think the 'statistical' effect and visual effect are designated seperately, so just copy the invisibility spell effect, and replace the visual effect shader with the one you want.

Nope. As soon as the archetype is set to "Invisible", the Predator-style effect is automatically applied. Any shaders I select either are ignored or have the invisibility effect applied to them as well. The visual effect appears to be hard-coded to the archetype, and I can't find a way to simulate invisibility (i.e. line-of-sight gets ignored by the detection system) without using it.

Ideally I'd like it to simulate low light levels, where the player could get detected by line-of-sight but at a much shorter range than usual.

Could you add a perk which vastly improves stealth?

Ah, bingo, I can just apply Blindness to all nearby foes. Should have thought of that sooner.

There are also perk entry points for Mod Detection Light and Mod Detection Movement, but I think they have to be applied to NPCs rather than the player, and IIRC perks don't work right when they're applied at runtime.