MTS has all free content, all the time. Find out how YOU can help to keep it running. Tell me how...

Postal Package Editor (and API)

by Echo Posted 9th Aug 2009 at 4:27 PM - Updated 27th Nov 2013 at 4:14 PM by Nysha
176 Comments / replies (Who?) - 25 Feedback Posts
Postal is a DBPF3 package editor. That means that it can open up Sims 3 package files, let you poke at their innards, change things around, then save them back into new package files.

Can I run it?
Postal is built on top of Java 6, so if you can run Java 6 then the answer is "yes". That includes Windows XP, Vista and Mac OSX. If you can run the Sims 3, you should be able to run this.
There is one caveat though. Because I'm running Windows, I cannot test well on Mac. Please let me know if you experience any issues.

What can it do?
Postal can navigate all kinds of Sims 3 package files, and parse/display/write many resources, including OBJDs, OBJKs, STBLs, XMLs, CSTRs, GEOMs, NMAPs, DDSs, PNGs, VPXYs, Texture Compositors and the various text-based formats. As time goes on, the number of resource types it can edit is growing.

Postal also has a filetable which keeps track of all the resources that can be used in game. You can use this to search for resources by type, group, or instance, wherever they come from. Postal has a scripting console, and a plugin architecture to allow you to add your own functionality to the application.

The Postal API
The Postal Editor is built on top of the "Postal API". This is a library which speeds up the process of writing custom tools which can read from and write to package files and the resource types inside them. The API is available under a BSD license, which essentially means you can use it however you like in your own tools as long as you acknowledge the original creator and point to a place where the original source can be downloaded. (The full Postal GUI is available under a GPL license)

The Postal API has already been used in other tools, including The Sims 3 Mod Generator and Merlin . There is some documentation on how to use it to build your own applications and how to extend the Postal environment attached.

- Go to and install the up-to-date version of Java for your operating system (if you don't already have it)
- Download the latest version of the Postal installer from
- Double click on the file you have downloaded, and follow the Wizard. Make sure you put in the correct path to your Sims 3 installation when it prompts you!

* Mac OSX users, please see this post regarding running Java 6

Additional Credits:
Most of the behaviour here is based directly off the wiki pages describing file formats and resource structures. Thanks to Rick, Karybdis, Delphy, WesHowe, Inge, Peter, Atavera, Pescado and the many others who have contributed their knowledge to that collective effort.
Tags: #Postal, #DBPF, #editor, #api, #stbl, #dds, #geom, #xml

Operating System: Windows Linux Mac OS X
Utility Type: CC Editors
Plugin Type: Not Applicable

You must have the expansion or stuff packs listed below installed to use this custom content. Please see the post text for any exceptions.

Sims 3
Key: - File was updated after upload was posted
Filename - Tip: You can click the magnifying glass to see the archive contents Size Downloads Date
user-installation.rar | Install instructions (same as in post)

Size: 388 Bytes · Downloads: 21,137 · 10th Aug 2009
388 Bytes 21,137 10th Aug 2009
FOR-DEVELOPERS-ONLY-Postal-developer-guide-PDF.rar | Documentation for developers interested in using Postal in their own tools

Size: 308.1 KB · Downloads: 10,149 · 10th Aug 2009
308.1 KB 10,149 10th Aug 2009
Don't forget to Thank the creator after downloading! Use the Thanks button located above the screenshots above.
Quick Guide:

1. Click the file listed on the Files tab to download the file to your computer.
2. Extract the zip, rar, or 7z file. Now you will have either a .package or a .sims3pack file.

For Package files:

1. Cut and paste the file into your Documents\Electronic Arts\The Sims 3\Mods\Packages folder. If you do not already have this folder, you should read the full guide to Package files first: Sims 3:Installing Package Fileswiki, so you can make sure your game is fully patched and you have the correct Resource.cfg file.
2. Run the game, and find your content where the creator said it would be (build mode, buy mode, Create-a-Sim, etc.).

For Sims3Pack files:

1. Cut and paste it into your Documents\Electronic Arts\The Sims 3\Downloads folder. If you do not have this folder yet, it is recommended that you open the game and then close it again so that this folder will be automatically created. Then you can place the .sims3pack into your Downloads folder.
2. Load the game's Launcher, and click on the Downloads tab. Find the item in the list and tick the box beside it. Then press the Install button below the list.
3. Wait for the installer to load, and it will install the content to the game. You will get a message letting you know when it's done.
4. Run the game, and find your content where the creator said it would be (build mode, buy mode, Create-a-Sim, etc.).

Extracting from RAR, ZIP, or 7z: You will need a special program for this. For Windows, we recommend 7-Zip and for Mac OSX, we recommend Keka. Both are free and safe to use.

Need more help?

If you need more info, see:
176 Comments / Replies (Who?) - 155 Feedback Posts, 10 Thanks Posts
Hide Thanks Posts for this thread (Show only feedback)
Page 3 of 8
Test Subject
#51 Old 27th Aug 2009 at 3:47 PM
Thanks Sometime I will figure out how to use it lol. Does anyone know if there is a way to run sims that you download through a Clean Installer like in sims 2? Is there a program/mod for sims 3 yet?
Lab Assistant
#52 Old 30th Aug 2009 at 12:24 PM
Following plasticbox suggestion with the installation path: there are two small errors.
The first is that the folder has to be named "The Sims 3.localized" and not simply "The Sims 3", and the second is that the standard path has backslashes in place of slashes, and OS X doesn't use those for directories.

Everything can be fixed simply typing the corrections in the field. So, instead of

/Applications/The Sims 3/The Files/\Electronic Arts\The Sims 3

you'll have

/Applications/The Sims 3.localized/The Files/Electronic Arts/The Sims 3

(corrections are highlighted).
Test Subject
#53 Old 31st Aug 2009 at 12:06 AM
Hi Echo

I really like this tool but I'd need your help For my next project I replaced the texture of Moon (fortunately it was easy to find the dds texture) and it works fine in game but I'm curious if I can edit the mesh of Moon too do you know does it actually have a mesh? (I assume it must have since it isn't bounded in the sky because the nightsky also has a dds texture - as I experienced)

I tried to filter all the things by filesize and search for it at less size things - because I assume it's a simple plain square - but there are so many modls, mlods, and geoms that I don't even know from the 3 formats in which I should find it..

Hope you can help me how to find the mesh if it exists at all Thank you! marci
Retired Duck
retired moderator
Original Poster
#54 Old 31st Aug 2009 at 1:58 PM
senemm, I expect there is a mesh, but I'm not sure where to find it either. What you can try is File > Search Filepath, then type MLOD (or MODL, but probably not GEOM, they're body meshes) into the "type" field and click search. Once you get a list of all the MLODs, you can get Postal to show you their names by going to Workspace > Show Nmap Names. It might make it a bit easier to tell what you're looking at/for.
Lab Assistant
#55 Old 6th Sep 2009 at 4:42 PM Last edited by Claire DC : 6th Sep 2009 at 5:25 PM.
Ignore me, I believe I am an idiot haha. x
#56 Old 9th Sep 2009 at 9:25 AM Last edited by Jasumi : 9th Sep 2009 at 9:49 AM.
When I try to install this program, it shoots me an error: "This directory can not be written."

I am running on x64 Windows Vista.


Per my suspicions, it 8is because Vista does not allow .Jar files access into Program Files. Turning off UAC fixed this issue.
Retired Duck
retired moderator
Original Poster
#57 Old 9th Sep 2009 at 10:57 AM
Jasumi, yes, you're absolutely correct. You can install Postal to another location though, that way you can leave UAC turned on.
Lab Assistant
#58 Old 11th Sep 2009 at 3:53 AM
hello corredt filepath to sims 3 installation what does that mean.thx
Retired Duck
retired moderator
Original Poster
#59 Old 11th Sep 2009 at 9:44 AM
You need to tell the program where your Sims 3 is installed. The default path is probably the most likely place for it to be.
Retired Duck
retired moderator
Original Poster
#60 Old 13th Sep 2009 at 2:20 PM
Version 0.8 has now been released
You can download it from SourceForge using the link in the first post ( )

Details of the changes are as follows:

API Changes
- CAS Part parsing
- Rewrite of the GEOM parsing
- Back end read/write of complates, package manifests and pattern lists
- Back end compression code

GUI Changes
- Rework of the GEOM 3d preview. Previews now render with their overlaid greyscale textures, and should work on all operating systems without native libraries.
- Created .exe wrappers for the Postal application, installer, and debug mode. This should make it less confusing for Windows users to start Postal
- Set up Postal command line to accept file paths as parameters. This means that you can right click on a package in explorer and select "Open With", "Postal", and have Postal start up with the file open straight away.
- Read-only view of CAS Parts

General bug fixes
- Fixed an issue where, if you added a new resource to an empty package, you could not edit it without saving and re-opening the file
- Fixed an issue on Windows machines with custom file dialog icons, which would make the file picker window stop working
- As part of the GEOM rework, removed a lot of native 3d rendering libraries, reducing the size of the application by about a third.
Forum Resident
#61 Old 14th Sep 2009 at 9:24 PM
Hi echo, I knew you would do something phenomenal. Thank you so much!!!!

If a cluttered desk is the sign of a cluttered mind, then what about an empty desk?

My stuff may be used in uploads if 1. Credit is given, 2. link to my page provided. Happy simming!
McAlli's page
Test Subject
#62 Old 15th Sep 2009 at 4:04 AM
Alright, want to use this. Can't open/install. It didn't have a default exe to open it with, so i updated my java. tried java.exe, tried javaaw.exe, made sure the justsched.exe was running before i tried it, and... still no dice. It tells me it cannot find the main class. I took a java class once upon a time, i didn't do too well.. so.. I don't trust my judgement when it comes to java. Any idea how i get this installed so I can actually use it.

*reads above comment* Neeeevermind! *downloads, tries again, success! Hooray! Jubilation!*
Test Subject
#63 Old 16th Sep 2009 at 6:05 PM
Hi, this is a very useful program.
I have a question. Is there a way to preview the package image? For example I wanted to open some of my .package hair files that I want to delete from the game but I can't preview them so I don't know which is which. Is there a way to preview them with postal? The dds preview doesn't help identify them as they would look in cas.
Top Secret Researcher
#64 Old 21st Sep 2009 at 8:08 AM
Can Postal import a PNG or DDS file to simply replace texture of an object? S3PE can do that, but it can not preview anything, so it makes things complicated. The Import PNG button is grayed out. Did I do something wrong?
Retired Duck
retired moderator
Original Poster
#65 Old 21st Sep 2009 at 11:20 AM
Hi tomomi,

It can certainly import a DDS, but at the moment the PNG import is a little bit unpredictable so I've disabled it.

To import a DDS image, click over to the "Hex View" tab and click "import". Find your DDS image, then click the "Open" button. All done! You can jump back to the "Image" tab to check everything went fine.

I really should add an "Import DDS" option to the main image pane. I'll put it on my to-do list! :D

Originally Posted by tomomi1922
Can Postal import a PNG or DDS file to simply replace texture of an object? S3PE can do that, but it can not preview anything, so it makes things complicated. The Import PNG button is grayed out. Did I do something wrong?

ericabain, I'm not sure what you mean by "preview". If you mean custom GEOM (body) meshes, then yes, you can preview them by selecting the GEOM file from the and clicking the "3D preview" button. Textures (DDS and PNG) can be previewed just by opening them. I haven't written any handling code for 3d object meshes yet, so they can't be previewed at all. If you want the ability to preview all your package files with thumbnails of their content though, then no, it can't do that.
Test Subject
#66 Old 29th Sep 2009 at 2:53 AM
I and my Mac thank you for this very much, and I have 1 question. Can this be used to edit funds of families not yet placed in the neighborhood? Like in SimPE you could edit funds of any family, so can this do that as well?
Retired Duck
retired moderator
Original Poster
#67 Old 29th Sep 2009 at 3:24 AM
jbyrns, unfortunately this tool is meant for editing general game files, not really for editing neighbourhood files. As such, I don't think you can really edit families with this easily.
#68 Old 30th Sep 2009 at 6:09 PM Last edited by Base1980 : 1st Oct 2009 at 12:13 AM.
Thank you so much!!

A few questions tho
Is it possible to delete lines from a package, lets say a complete DSS file?
Can i edit the CAS part data XML? like changing links to files or delete them?....It doesn't work double clicking the lines(popup window appears) and edit/import/export or commiting changes.
Changes i try to make(changing instance number or such) never get applied.

Thnx again!!
Retired Duck
retired moderator
Original Poster
#69 Old 1st Oct 2009 at 1:38 AM
The CAS Part data view is strictly read-only at the moment, because the file isn't *just* xml, there are a lot of other things which have to be kept in sync and that logic hasn't been written you.

I haven't got an option to remove something from a package at the moment, but I will add it.

Changing instance numbers should work fine, as long as you "commit" after changing them.
#70 Old 1st Oct 2009 at 8:40 AM
Thank you.
Test Subject
#71 Old 3rd Oct 2009 at 5:43 AM
so you can use this tool to edit what the billboards say! yay!


Hope you have a good day ;) I'm in Australia so I am probably sleeping :D
Add Bacon???
Test Subject
#72 Old 26th Oct 2009 at 10:28 PM
Can you change text descriptions with this tool? Or is there something simpler and better for this purpose?
Test Subject
#73 Old 6th Nov 2009 at 12:00 AM
Hey guys,
I tried installing this tool on my Windows Vista 64 but I doesn't work... I already updated Java and tried installing the tool with the .jar-program. It still says that i need JRE 1.6.0_06...

Could someone help me with that? Any idea?

Sorry for bothering...
Retired Duck
retired moderator
Original Poster
#74 Old 6th Nov 2009 at 3:24 AM
Betty Lou, do you know what version of Java you do have installed? At what point is it failing?
Test Subject
#75 Old 7th Nov 2009 at 9:25 PM
Is there a way to find out the hair package related to a ".sim" file with this tool?

I downloaded a few ready made sims which require custom hair. Is a reference to the original hair package hidden in the .sim file at all?
Page 3 of 8