Whatever it takes. If you have an essentially top-down view of a maze, it really is quite pointless...

Make it so that the entire area is covered with black effects, and make actors emit a clear effect, but make it grey when an actor can not see in an area.
Tada.
(I make it sound so easy!)

I'm afraid this would lag too much, no? The maze is quite large.

If you wanted to make it really hard, you could make every actor emit a gigantic black effect and have a bit of clear in the middle.

The good news is you only have one actor in this mission and I just want to prevent Q/E- looking.
The bad news is you only have one actor in this mission and you'll be blind.

SceneMan:SetObservationTarget() = self.Pos;

Does that just prevent you from looking away from your actor?
I will probably still need the black effect + transparent circle, as I only want the actor to see 144 pixels away, or 1 1/2 standard bunker modules.

Yeah but people with higher resolutions will end up cheating anyway.

You could spawn an MOSR but you'd still probably end up seeing terrain, and any glow that big is both going to lag and be slightly transparent anyways.

Well, can anyone help me out with a little code that will make my actor emit my hug black "glow"?
Possibly an MOSR version like Grif said would help too.

Would it be possible to add it as a UI element? MOSRs don't obscure health displays, IIRC, and neither do glows, so you would always know where enemies are.

I'm not sure....isn't the UI hardcoded? I've never seen a UI mod so I wouldn't know.

The UI is hardcoded, yes. There's no perfect way to do it.

do it grifs way. just center the screen on your actor. best work around possible at the moment.

I'll just delay this mission until a better way becomes available then. Seriously the vision has to be very limited for this maze to work. Even centered at lowest resolution you'll see like 3-4 bunker modules away, which is over twice what I want it to be.

Fill the maze with module-sized blocks of blackness that disappear if your controlled actor is close enough. Even if the maze is fairly large, it's unlikely to be more than a few hundred standard bunker modules - with a fairly simple script, the blackness blobs won't hurt your framerate too much, and your maze will look like a sort of a roguelike.