Mapmaking 101 – Secret Passages and Caves, Part 1
A couple of articles with a difference this time. I was asked by Kolja Silvani, the author of these articles, which appear on a German Stronghold fansite, if I could put them up here.
Secret Passages and Caves
By Kolja Silvani
Adapted to English by Jayhawk
The original article can be found here
This article has been split up into three parts, out of kindness to those that have a slow connection.
Introduction Secret passages and caves are based upon something that may be a bug, namely that diagonally connecting bits of (high elevation) terrain can be passed by through by units. We can only hope this bug will not be fixed. Note: I don’t think it’s a bug as much as a feature, using the same algorithm which allows units to pass walls that only connect on the corners. — Jayhawk
How to build a secret passage
First you fill part of your map with the Maximum Elevated terrain brush. Once you have made a nice outcrop of rock, you use space to lower the terrain view and make life easier on yourself. Next you select the smallest brush and set it to paint the lowest terrain height. With this brush you draw a line in which the squares connect only at the corners. You can make this path as curved as you like, as long as you connect only the corners. The secret passage can be recognised by its green squares on the rocky background.
This will get you your basic secret passage.
Picture 1: A basic secret passage.
Note: the picture shows you the lowered view.
Secret passages are easy to make, but it’s a little harder to understand how they work. As said before open spaces, that connect on the corners are passable as well, however, this alone would not make a passage secret. More important is that on the surface units can cross these same diagonals, making movement virtually unhindered by the passage. The picture below shows some of these diagonals highlighted in red.
Picture 2: Showing connections.
Now we can do a little more on hiding the secret passage. To do so you can use pebbles, shrubs and even trees. When used with care, they will hide the passage even from those that use the spacebar to check a map.
Picture 3: Camouflaging your passage.