SimCity 4: Create your own Custom Regions

To create a custom region in SimCity 4 you will need to create or obtain a terrain image and to provide an appropriate configuration file.

Download the files used in this tutorial.

• Terrain Image
• Configuration File
• Region Size
• City Spaces
• Building a config.bmp
• Installing a Custom Terrain
• Mars Example
• Screenshots of Mars

Terrain Image

The terrain image needs to be an 8 bit greyscale BMP or JPG image. SimCity4 maps the greyscale to elevation, value 0 being the lowest point, sea level is at 85 and the beach starts at 86. The highest point that a mountain can reach is a value of 255.

You can create your own image or you can create a region from real life. To create a region from real life you will need some Digital Elevation Model data. There is a good article at Rebel 13's Sim City Site that goes in to detail about obtaining and converting DEM data in to an 8 bit greyscale image. Rebel 13's Sim City Site also has a large range of terrain images ready for use, including those created from DEM data taken from the orbits of Mars and Venus.

Configuration File

The configuration file, config.bmp, can be found in your regions folder stored in your My Documents folder and not in the Program Files folder. The config.bmp file configures two lots of information for your region. Your regions size and the distribution of city spaces. City spaces sizes are small, medium and large.

Region Size

A standard region has a terrain image of 1025 pixels x 1025 pixels with a config.bmp of 16 pixels x 16 pixels. This equates to the terrain image being 64 times bigger plus 1 pixel.

(16 x 64) + 1 = 1024 + 1 = 1025

The smallest region that you can have is 65 x 65 with a config.bmp of 1 x 1. This gives you a tiny region with one small city space. No fun there then!

The largest region you can have is 1281 x 1281 with a config.bmp of 20 x20. This gives you a large region with 25 large city spaces or the equivalent combination of small, medium and large spaces.

City Spaces

The contents of the config.bmp determine the layout of the city spaces. Below left is an enlarged example of a standard sized config.bmp. You will see that there are three different coloured blocks that map the layout for the city spaces. The blue blocks are 4 pixels x 4 pixels, the green blocks are 2 x 2 and the red blocks are 1 x 1. An all blue config.bmp gives you all large city spaces and an all red config.bmp will give you all small city spaces. The below right image has been enlarged for display purposes.

Building a config.bmp

1. Start with an all red config.bmp of the correct size for your terrain image and zoom in to get a good look at it.
2. Download the above city_size_picker.bmp in the correct scale, open and zoom in to get a good look.
3. Open your terrain image and decided where to place large city spaces.
4. Select the blue square and copy it.
5. Paste blue squares on the red background in positions where you want you large city spaces.
6. Select the green square and copy it.
7. Paste green squares into any red gaps that are big enough to hold medium city spaces.
8. All the red that is left over becomes your small city spaces.

Installing a Custom Terrain

1. In your My Documents folder locate and open the Regions folder in the SimCity 4 folder.
2. Create a new folder and name it to your new region.
3. Copy from another region a region.ini file.
4. Open region.ini and edit the name to that of your new region.
5. Place your terrain image and config.bmp file into the new region folder. The terrain image doesn't have to go here, you can store it elsewhere.
6. Launch SimCity 4 and open the new region. You will notice that the terrain is flat and divided into the city spaces laid out in the config.bmp.
7. Press alt-shift-ctrl-r and a file dialog window will appear.
8. Locate your terrain image and press OK.
9. If all is well the import process can take between 5 and 15 minutes depending on your system and the quantity of small city spaces it has to create. (Try and reduce your quantity of small city spaces if you want a quicker import.)

Mars Example

Download the Mars terrain by Aaron Ashley. It has been cut down to 1281 pixels x 705 pixels and flipped to place the water in the south of the finished region. Using the advice from the article at Rebel 13's Sim City Site the contrast has been adjusted until the water level is at a desirable level. The below left image has been reduced. Using a config.bmp of 20 pixels by 11 pixels the city spaces have been arranged to best suit the terrain. The below right image has been enlarged.

Screenshots of Mars

Below are some screenshots of the finished region. You will notice that trees and animals need to be placed before establishing a city.

Your mission, should you accept, is to colonise the newly terraformed Mars. Have fun!

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