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SimCity Blog: The Extended Worker Data Mod and more


Hello again, Mayors – I’m Guillaume Pierre, the Lead Gameplay Scripter and a designer on SimCity. You may have read the recently published SimCity Modding Policy postedhere and have wondered how to make Mods yourself.

Today I’m going to talk about a few Mods I’ve been working on. I hope this helps you make your own. Please note, these Mods are to be used strictly at your own risk, as they don’t go through a testing process like an official game update would. As you may already know, there is no official SimCity Mod tool set, so I’ve used a third-party service,Oppie’s SimCityPak tool*.

The Extended Worker Data Mod

Have you ever wondered how many jobs of each wealth level a work building supports? This Mod adds three bars to the civic, commercial and industrial buildings rollovers that gives you just that information. It will also help you make informed decisions in regards to zoning for residential buildings.


In order to make this Mod, I created a new piece of UI with a matching data binding function. Fortunately, there was already an example similar to what I wanted to do in the MegaTower Office level rollover, so my first task was to copy the layout with the three bars into a new file.

I then looked up how the worker data was fed into the bars in the rollover, and copied that piece of JavaScript into another file. Because of the way the UI is packed in the game, I had to find a JavaScript file that is packed by itself rather than add the function to the main (and very long) UI file. To do this, I opened the Mayor Rating UI file and pasted the code at the bottom of it. I renamed the original “kSkyTowerLevelOfficePopulation” function to “kWorkers” and encoded it to “0xe15027f1”.

Finally, I went through all the units in the game that have workers (I actually looked for the code for “kMaintenance” and combed through the results) and added the new rollover item’s ID to their list of extended rollover data.

Get the Extended Worker Data mod here:

The Closer Road Guides Mod

This Mod tightens the distance tuning for road guides, so streets and avenues get placed closer to each other when using guides. As a result, there is very little empty space in the back of each building, so you can get more houses into your city.

You may not want to use this Mod if you turn off guides for curved roads though, as you might not get as many buildings developing.


In order to make this Mod I opened the SimCity game package file and exported a few files, including the global road template which is used by the avenues, and the narrow street definition files. Then I lowered the value of the guide distance (property ID: 0x0ec367af) and saved the files as a new package.

Get the Closed Road Guides Mod here:

The Purple Line in Industrial Tech Map Mod

This Mod takes the pink and purple lines that go from colleges and universities and directs them to factories and certain power plants that appear in the Industrial Tech Map. This is helpful to predict which factories are going to get skill first, and which ones are going to upgrade next.


In the code, these type of lines are called “pipe overlays”, as they are a visualization definition for agents that use the “pipe” handler. Adding the line that goes from the college to medium tech factories, and the line from the university to high tech factories was straightforward. I added a new property array listing them in the data map file and that took care of it.

The other lines were a little more complex to get working. First I had to create new pipe overlay files for the lines coming from the college and university to the lower tech factories, and to power plants by copying the original pipe overlay files. Then I made these new overlay files point to their correct pipe sinks. Finally, I added references to the new files in the same array as the original overlay files in the data map file so they all show up in game and provide context as designed.

Get the Purple Line in Industrial Tech Map Mod here:

That’s it for this time! I can’t wait to see what kind of amazing Mods you’re going to create. As always, I’m available to answer questions regarding this blog in the comments section below, on Twitter at @MaxisGuillaume, and in the Community-Generated Content section of our forums (

*Oppie’s SimCityPak tool is not endorsed by Maxis.


About the author


Reticulating splines...

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