A new approach to topography, or making a mountain out of a mole-hill?

Of course, I like to envision myself as the pioneer, but I know that when I have had such delusions in the past, someone points me to a web site that details how my ‘new’ idea has been perfected over the centuries… So feel free to bust my bubble; I’m used to it ;)

Also, this method may not appeal to many modelers, but the advantages I see are:

1. A highly accurate model of prototype topography

2. Really light weight

3. Minimum of material (related to 2. above, but also saves money, and I’m a cheapskate)

The disadvantage is that it’s a fairly pedantic approach that requires the ability to visualize terrain based on topographic mapping techniques.

The end result is a custom foam mountain or hill that’s a lot like those premade ones you see in your LHS; hollow and light light light.

Also, let me say that I have very little experience in this hobby. The layout that I have started (my first) is going to be very mountainous, and, probably due to my early training with topographic maps, it seemed natural to me that my track plan include topo lines. Way back in my early days in the Boy Scouts I saw an article on modeling mountains based on a topo map, and now I’ve updated and improved on that method. So far I’ve only modeled one mountain, but it has turned out quite to my liking, and I’ve learned a couple things in the process. My explanation here is going to require a good understanding of topo maps, a generous helping of imagination ;), and would be much easier to understand with pix. Unfortunately, I didn’t take pictures along the way, so I will do my best to explain what I did, and, if there is any interest, I’ll get some illustrative shots when I build my next mountain.

EDIT: I did another quick one, and added photos and descriptions in blue, below.

When I sketched my intended layout, I didn’t pay any attention to accurate spacing of topo lines, I just freehanded them to represent the slopes at a scale that made sense visually. However, the next step was to transfer the topo lines to the 1” construction foam, so accuracy was important at this stage. At 1:148 scale, 1” thick foam represents 148”, or 12.3’, of elevation. Since the hill I wanted to model is about 130’ tall, I determined I needed 10 ‘thicknesses’ of foam, and therefore 10 topo lines. Then:

1.       Starting with a piece of the foam that was a few inches larger than the base of my mountain, I traced  the topo line representing the base of the mountain. I’ll call this topo line #10.

2.       Guesstimating where the top of the mountain would be in relation to the base, I drew in the highest topo line, so that I now had a ‘circle within a circle’. I call this topo line #1.

3.       To assist in drawing the remaining 8 topo lines, I placed 8 dots along each of several ‘slope lines’ around the mountain. Of course, the dots are closer together to represent steep slopes, and farther apart to represent lesser slopes. I took care to place the dots along ‘critical’ slope lines that represented features of the mountainside. For instance, a gully running up the side of the mountain might require a slope line running along each ridge of the gully and a slope line running along the trough.

4.       I then connected the dots, forming the 8 additional topo lines.

The following image illustrates the topo lines drawn on a 12" X 14" piece of 1/2" styrofoam:

5.       Using an electric carving knife, I cut along the topo lines to end up with one ring representing each 10’ of elevation. However, I angled the knife as I made each cut such that the resulting foam ring would be wider at the bottom than at the top. This way the rings can be easily stacked and glued together. I started with the highest (#1) topo line, and tried to angle the knife so that the bottom of the cut would be directly below (on the opposite side of the foam from) the #2 topo line. When I cut the #2 topo line, I angled the knife so that the bottom of that cut is directly below the #3 topo line, and so on. For the lowest topo line, I just angled the knife outward in a similar manner.

Here's a cross-section illustration with a regular knife and black dots for the topo lines. Notice how the knife is angled to exit the foam directly under the adjacent topo line:

6.       Then it was a simple matter of gluing and stacking all the rings to form the mountain. Of course, I wasn’t able to visualize the knife angles perfectly, but some simple foam shaping and a coat of plaster took care of that.

Here's another one I did, after I shaped it and covered it with colored plaster:

The steeper the terrain, the thinner the structure, to the extreme that if your terrain is too steep (a cliff), you will end up with a hole in the side of the mountain (where all the topo lines intersect) but this can obviously be covered with a sheet of your modeling material of choice (gauze and plaster, paper and plaster, whatever).

So, can anybody make any sense out of that without pictures? J