Difficulty Hiding Secrets on the Automap

IWAD:     DOOM2
Format:   UDMF
Editor:   GZDoom Builder
Port:     G/ZDoom

I'm having this issue, where secrets are spoiled by unseen (to the player) lines being drawn through impassible walls. It seems to happen around sectors [near the secret] that I've height adjusted, then 'hidden' from the automap. It seems the player is sometimes able to see through these and into the secret itself. Example: See bellow the screenshots of a SLIME01 river that leads into a wall, apparently betraying the secret, even though no connection exists between them.

A second issue, which is equally confounding, is how the player can sometimes see the other side of a secret door on the automap! Even if I have the linedef the player can actually view in-game is tagged as 'secret.' (You can see an example of this also near the bottom of shot 3.)

I could always mark these secret areas as 'hidden' entirely, but that just irks me, for aesthetic reasons. Screenshots illustrating my quandary follow:

1. [DB shot w/ secret areas highlighted]
2. [DB shot of view of secret entrance]
3. [In-game shot of lines being drawn through wall, where the player is facing]

Any help would be appreciated.

Edit: My previous solution wasn't applicable in this situation.

Question though: does the secret entrance (the door) have a step? If its floor is not flush with the surrounding floor, I think the player might still be able to see inside it.

Thanks, EarthQuake; this is all great advice. I've noticed that jiggering with the vertices sometimes works, but I never thought of any of your other suggestions.

I'll update my progress as I go. Certainly, a tidy automap must be a priority for more mappers than myself.

Heh, sorry for the ninja edit, I actually missed the second part of your post where it might have been applicable. It's sort of been a while since I even had a need to make such secret areas, so I'm a bit rusty on how it all works. Hopefully you find a solution though, cause I know how annoying things like this can be.

No problem. That's exactly what one should ask if a self-proclaimed newb at mapping comes around asking such questions. [:

But no, the height of all the sectors that connect the non-secret play-area with the secret area are 0.

(This is a terrible explanation)

It looks like the sector hiding the secret area has its floor & ceiling a bit over halfway up the wall? IIRC if you want to prevent the engine seeing through the "blocking" sector the floor & ceiling of the blocking sector cannot sit between the floor and ceiling of the adjoining non-secret sector (even if the blocking sectors height is 0).

Thanks, traversd. I think I understand what you mean.

And I'll definitely note that, but this secret is no longer a problem, either because I re-jiggered its vertices, or because I switched to "ZDBSP - Compress nodes (UDMF)" (I'm not sure what did it, but I list my steps for future members searching for this topic). Though I do have a similar problem in other areas, and have just resorted to marking the linedefs inside the secret as hidden. It's an ugly, inelegant solution, but I'm at my wits' end. :/

You're right about the 'door' sector being not flush with the floor (ceiling/floor are at height 96). But what's weird, is that in-game I don't seem to be able to 'see' through that part on the automap, but if I hump the wall where the SLIME river goes into the wall, angling my vision where the secret is, it renders a couple of the linedefs on the inside of the secret.

Would be nice if there was a flag, or a property, to make linedefs 'block automap "vision,"' but alas, there doesn't seem to be such a thing.

Thanks again for your suggestion. If you(or anyone else)'ve got any other ideas, I'd be glad to hear them; and if I find a solution, I'll definitely update this thread.