Dungeon Secrets – Secret Corridors

You can’t make a good dungeon without having some secrets, right? Hidden traps, secret doors, concealed corridors, illusory floors, invisible enemies and fake treasure. Now, placing invisible enemies on the map is dead simple (trick being not actually placing them at all) but how can I make a map with a secret corridor that I can reveal and hide at will, and not betraying it’s existence when it is hidden?

CC3+ has nice tools for adding corridors to your map, but you have do decide if they should break the wall or not when connecting to an existing room or corridor. And this is where the challenge begins. It is easy enough to temporarily hide something by putting it on it’s own layer so toggling the visibility of the corridor is easy, but if you chose to have it break the wall when placed, you would still have that hole there when the corridor is hidden. Now, that isn’t actually a good way to keep it secret. On the other hand, if you chose to not break the walls, then there will be walls blocking the corridor even when it is revealed, which look a bit weird, and we can’t have any of that, can we?

For this article, I am starting with a small mini-dungeon I made in the Jon Roberts dungeon style. The walls/floors here are drawn as a continuous entity to make sure both the walls and floors lines up nicely without any breaks. This can easily be done by either use the DD3 room tools and doing a polygonal room, or by using the regular drawing tools and draw first the floor as one entity, and the walls along it afterward. For bigger, more complicated dungeons, you’ll usually want to draw it in stages instead, and for that the DD3 room and corridor tools offer the best option since it can automatically connect to rooms and break walls.

I’ll look at two ways to handle our secret corridor.

Let’s just use the color key effect

This is the simplest option and rely on the color key to just chop a piece out of our wall. And what is great with this is that the polygon used to define the whole also can be put on a layer, so it can be show or hidden along with the secret corridor.

The setup here is quite simple. I start with my example map and I then drew a corridor between my two rooms as with any other corridor. You could do this using the DD3 corridor tool, or just use the regular drawing tools to draw a floor and a wall. Note that I mentioned earlier that all the rest of my floor was a single entity to give a connected look. Since we are going to be showing and hiding this corridor, it is important that it is a separate entity. This means it may be a bit more difficult to line up the floor pattern if needed, but then again, the dungeon floor technicians probably didn’t build the secret passageways as an integral part of the dungeon anyway.

Now, let us draw the polygons for the color key effect. Since this is supposed to cut a hole in our walls, we obviously need to put them on the WALLS sheet, so set this as the active sheet. Also set the current layer to SECRET the current color to  color 6  and the current fill style to Solid. Also check that line width is 0. Now draw two polygons covering up the walls that need to disappear. If you want perfect precision here, I recommend turning on a snap grid with a 0.5′ snap distance (we need 0.5 because the walls are 1′ thick, and that means it extends 0.5′ in each direction from the center line, which is also the edge of the floor. 0.5 snap distance can for example be set by setting the snap grid to 5 feet with 10 snap divisions). It doesn’t really matter if your polygon extends out into the room, the important part here is that it doesn’t cover more wall than it should (and that it cover enough wall).

Now, bring up the effects dialog, and add the Color Key effect to the WALLS sheet. Leave the color at the default value (it should be the same as the color we drew our polygons in), and move the effect upwards so it becomes the top effect in the list on the WALLS sheet (If you leave it below other effects like Glow, Bevel and Shadows you’ll find that the effect won’t work as you want it to, effect order matters).

And there we go, a perfect corridor connecting the two rooms. Because bevel and glow as applied after the color key, you can even see that the wall gets a bevel at the point where color key removed it, like it actually ends there.

But wait, we did want this to be a secret corridor, right? Well, there is one final step. Use change properties on the corridor floor and walls, and set the layer of these to SECRET (Same layer we put the color key polys on. And that’s it. If the SECRET layer is shown, the corridor shows up, but if you hide the SECRET layer (remember you can’t hide the active layer, so make sure another layer is marked active before hiding SECRET), it completely disappears, leaving no trace of it’s existence at all. Your players can no longer just look at the map and deduct that there is a secret corridor there, but will have to relay on whatever clues you wish to leave them.

You can grab my test map and test out this by hiding or unhiding the SECRET layer in it.

Let’s just make a hidable wall instead

Instead of using an effect, we can just make a section of the wall that can be hidden. The disadvantage with this approach is that you need to manipulate two layers when showing the corridor, you need to both hide the layer the wall is on, and then unhide the layer the corridor (and it’s side walls) is on to show the corridor, and the opposite to hide it again. If you only remember one of them, it won’t look right. It is also critical that the corridor segment you wish to hide do not have end walls. With the color key effect above, it didn’t matter, because the color key would actually end up hiding the end walls in the corridor at the same time as hiding the room walls, so you wouldn’t see any difference, but since we are relying on having a wall segment on a layer we hide, if the corridor had end walls, they would just show up instead.

As above, start with drawing the corridor. Remember to not break the room walls where you connect it.

Now, there are two ways to proceed. Either, we can just make two Split points where the wall break should start and end. This leaves us with a “loose” piece of wall that we can put on a different layers. If you go this route, put the corridor and side walls on the SECRET layer, and the pieces of wall on the SECRET2 layer (you need to make the latter yourself). Now, to hide the corridor, just hide SECRET and show SECRET2, to show it, show SECRET and hide SECRET2.

This is simple enough, but it has the disadvantage of the wall having cut points. Depending on the texture used for the wall, these may be visible in your map (or not), potentially betraying the position of a secret.

Another approach is to put the whole dungeon wall on the SECRET2 layer, and a copy of the dungeon wall on the SECRET layer, but with a piece cut out of it at the corridor opening. So basically, instead of just showing/hiding a small wall segment, you are showing/hiding the entire dungeon wall (or a large segment of it, like the entire length of a wall or an entire room, whatever works best). This approach ensures that there are no visible splits in the wall, but also means you have two identical walls to update if you want to make any changes.

When cutting the wall for either version, use the same snap settings as we used when drawing the color key polygons, i.e 0.5′ snap distance, so we can cut it exactly at the edge of the crossing wall instead of where their centers meet.

I’ve implemented both in my test map, and you can test it by hiding SECRET2 and showing SECRET3 (Made 2 new layers since I used SECRET for the color key demo). I’ve cut a gap in the wall on the left side, and I am replacing the entire wall on the right side. Zoom in and see if you can spot the pattern breaks. The pattern in the wall do make them a bit difficult to see, so you may be quite happy with that outcome, but it really depends a lot on the actual texture of the wall.


If you like, instead of manually going into the layers dialog and hiding/unhiding layers, you can make a hotspot with a macro that does it for you. This is especially useful when multiple layers are involved. I discusses this in the Hiding and Showing Map Features article.



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