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Regional Customization Part 1: City Plot Layout

We’ve all seen it: the default region layout, created when you first make a new region. Many users prefer the default layout, but some aren’t content with the large plots in the corners, and small maps in the center. Most new SimCity 4 players don’t even know you can change the region layout; however, there is a way, and it’s amazingly simple once you get the hang of it. So here it is: How to Change Your New Region’s City Layout.


Immediately after you create a new region the game creates a new folder for it in [i]My DocumentsSimCity 4Regions[region name][/i]. Assuming you haven’t saved any cities in that region, the folder should be empty except for the file [i]Region.ini[/i]. If you ever want to change the name of a region, just rename the folder to the new region name and edit this file in Notepad. In order to change the layout of your region, this folder MUST be empty; otherwise some or all the cities saved in the region will be permanently deleted (unfortunately, it is impossible to change the layout of an existing region without ruining your terraforming and destroying a lot of cities). It is highly recommended that you follow these directions for a new, empty region ONLY.


To change the arrangement of large, medium and small maps in a region you’ll need to add another file to the region’s folder, titled “Config.bmp.” Open Paint (most image editors work, but Windows Paint is best) and make a new image. Under ImageAttributes… set the size of the image to the size you want the finished region to be, measured according to one small-size map per pixel; a region is scaled with one small map (and thus one pixel) per kilometer. So if you want a region eight kilometers wide (eight small maps, or four medium maps, or two large maps), make the image size 8 pixels by 8 pixels. The region doesn’t need to be square, either; it can be any rectangle you care to make it, as long as it’s not too large (any more than 8 large maps on a side would be really excessive, unless you have a fast computer and a lot of time to build your cities :wink:). You should have a white picture the size of the region you want to make, and now the fun begins.


When the game opens your new region after you’ve made your Config.bmp file, it will read that file and re-create the map layout according to the way that image is colored, and the way you color that image determines the arrangement of the maps. Imagine you’re looking straight down on your region; the region is arranged into a grid of small maps, some of which are joined together in squares to make medium and large maps (medium 2×2, large 4×4). Your Config.bmp image works the same way; RGB (Paint default) Red will make small maps, RGB Green will make medium maps, and RGB Blue will make large maps. Making small maps is simple; every pixel colored red will make a small map tile in the region. The other two work the same way, only you always have to make your medium maps green squares 2 tiles wide, and your large maps blue squares 4 tiles wide. If you want holes in your region (in the middle or on the edge) just fill those spaces with another color; black, white and RGB Purple work well.


Once you have the Config.bmp image (and thus your region) drawn just the way you want it, save it as a 24-bit bitmap in the same folder as the region you want to change. Be sure it’s the correct folder, or you may accidentally destroy parts of another region. Then open the region you edited in SimCity 4, and if you did everything right the region will look the same way in-game as it does in your image editor. If there are any “holes” or places where city tiles seem to “overlap,” go back to your Config image and make sure you followed the format correctly; most problems with new region layouts happen because the image format wasn’t correct, and the colors didn’t match up with the size of the squares they occupy. If you reload the new region and find it completely devoid of cities, go back to your Config image and make sure the colors were all correct; the following is a breakdown of the colors required:

Red (For Small Maps) – Red 255; Green 0; Blue 0
Green: (For Medium Maps) – Red 0; Green 255; Blue 0
Blue (For Large Maps) – Red 0; Green 0; Blue 255
Purple (For Holes) – Red 255; Green 0; Blue 255

To ensure the colors in Paint are correct, double-click on the red, green, and blue colors on the Colors toolbar, and under “Define Custom Colors” make sure the Red, Green, and Blue values correspond to the above chart.


Here are some examples of different region layouts; keep in mind that region sizes are limited only by how much region your computer can handle (not to mention your imagination), so you don’t have to make your regions this same size or design.

This is a simple 8×8 small map Config image, shown magnified 8x in Windows Paint…

And its resulting region in SimCity 4:

Getting more creative, you can mix and match city sizes however they fit:

You’re not limited to square regions, and they don’t even have to be perfect rectangles:

Be sure your Config image follows the correct format, however. This region doesn’t work because the colors are switched around:

Once the region is divided into cities the way you want it be divided, then you can import a heightmap if you want, or just start terraforming and building. Take note though: once you start building on a region, you must never remove or modify that Config.bmp file. Doing so may destroy some or all of your hard-earned region as soon as you load the game.


Generally speaking, it’s easiest to design your regions from large maps, to small maps; draw in the large maps first, then draw the medium size maps, and finally fill in the spaces with small maps.

When designing your region layout, take into consideration how you’re going to build the cities on it. If you plan to have large metropolises with utilities provided by neighboring towns, make a few medium and large maps in central locations. Then make smaller maps bordering them and medium to large maps on the outskirts. If you’d rather have a few peaceful agricultural towns, build mainly large maps in the center of the region with medium and small ones to fill the edges.

Instead of designing a region with nothing but a straight grid of large (or medium, or small) maps, offset every other row, so that instead of bordering only four other cities, each city tile will be adjacent to 6 maps. Then fill in the spaces on the edges with smaller cities. Designing regions with each city bordering as many other cities as possible makes for more gameplay possibilities.

Try to avoid places where four maps intersect at one point; a “four corners” situation that can result in severe corner spikes during terraforming.

Good luck, and Happy Building!