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CAS Texture Unitool v1.9

The following is simply a guide/handbook/manual (however you want to look at it) for the CAS Texture Unitool (CTU). This is not a creation tutorial, so do not expect to specifically learn how to edit, modify or design textures from reading this.

RightArrow.gif Refer to CAS Tutorials for a list of tutorials. Or, poke around the MTS Sims 3 Creation Forum.
RightArrow.gif Check out the Niftyness section for Tips and Tricks.

What does this tool do?

The CAS Texture Unitool (CTU), is a tool that allows for editing and creation of Sims 3 CAS Parts. With this tool you can import custom textures, designs and meshes to create your own unique clothing for the game.

What do I need?

Windows XP/Vista/7

A PC running Windows XP, Windows Vista or Windows7.

OS X/Linux

OS X or Linux users may run this program with Mono 2.4 installed - See this thread for more details.

You need to make a set of folders to mimic the root file structure in the game. In your Users/<username>/Documents folder, make this exact structure:

Program Files -> Electronic Arts -> The Sims 3 -> GameData -> Shared

Then go to the location of your latest Sims 3 game app in your Applications folder, and ctrl+click to select 'show package contents' (if it's an alias you will have to ctrl+click to show original, and then ctrl+click on the original to show package contents).

Go to:

Contents -> Resources -> Transgaming -> c_drive -> Program Files -> Electronic Arts -> The Sims 3 -> GameData -> Shared

And copy the two folders and the resource.cfg in there into the corresponding folder you just made in your Documents folder. When CTU asks for your Sims 3 Root folder, point it to Documents/Program Files/Electronic Arts/The Sims 3

Microsoft .NET Framework 2.0
The CTU was built with Microsoft .NET Framework 2.0, so you must have have it installed! If you ONLY have Microsoft .NET Framework 3.5 installed make sure you have 2.0 installed as well.
Windows Vista/7 Users
Microsoft .NET Framework 2.0 is rolled into Microsoft .NET Framework 3.5.
DirectX Runtime (March 2009)

To run the CTU you'll also need DirectX Runtime (March 2009).

Where can I find it?

The CTU can be found here.

How do I install it?

  • Download and extract both the CasParts.rar AND the CasTextureUnitool.rar to the same place. A good idea is to create a new folder specifically for the CTU.
  • Once everything is extracted, you should see the CasTextureUnitool.exe and a bunch of other files, and then a casparts folder and an xml folder.

OS X/Linux Users

  • Download and extract both CasTetxureUnitoolNo3d.rar AND CasParts.rar to the same place.. Keep in mind that the OS X/Linux version does not have 3D View as of now.
KEEP FOLDER STRUCTURE INTACT: Do not delete/move/change or otherwise do anything to the file arrangement!

How do I run it?

Double-click on CasTextureUnitool.exe
Creating a Shortcut
For easy access it's a good idea to create a desktop shortcut. Simply right-click on CasTextureUnitool.exe and go to Send To → Desktop.

General Information

CAS Parts

A .caspart file itself can be thought of as a "placeholder" in Create-A-Sim. By linking meshes, textures and other details to the .caspart, you create what is commonly know as a CAS Part. CAS Parts are what a the game actually displays on the sim (i.e. shirts, shoes, watches, etc); this includes the mesh, shape, color, lighting, transparency or anything else that affects the look of the design.

DDS Files

A DDS file is a type of raster image, commonly used by many games, including both Sims 2 and Sims 3. DDS files can be saved in a variety of formats, both compressed and uncompressed. You will need to save your textures in DDS format for use in the CTU.

Image Editor
Your everyday run of the mill image editor like MS Paint or Paintbrush will not suffice for TS3 skinning. Instead you'll need a program that at least has these basic features:
  • RGB Mode
  • Channel View
  • Layers
  • Image Adjusters (i.e. desaturate, colorize, etc.)
Most people use Adobe Photoshop or Paint Shop Pro. However, there are free alternatives like GIMP or Paint.NET.

Many imaging programs do not initially know how to save/handle DDS files, so you'll have to install a plugin for them. Here are two of the most common ones.


The CTU saves your finished creations as .packages, similar to what was used with The Sims 2.

RightArrow.gif For help with installing .packages, see Installing Sims 3 Package Files

Getting Started

Creating A New Package

To create a new package, go to File → New. By default, you should be in the Find a CAS Part tab. Here is where you pick what mesh you wish to start off with.


To help quicken the search for a mesh, you can dial up the type of mesh you wish to use by setting the age/gender/type parameters.


Once you set the parameters, you can either pick the mesh you want to use from the drop-down list or you can select it using the Quick Find box by clicking on the thumbnail.


When creating new designs for your CAS part, it's a good idea to use the existing textures/meshes as guides.

To extract a mesh, simply click on the "Extract Meshes" in the Find a CAS Part tab.
Bump Maps
Additionally bump maps may be found under the Meshes tab. To extract, click on the appropriate TGI link then hit the find button. When the DDS preview window comes up, click the export button at the bottom right corner of the screen.


The easiest way to extract textures is to use the "Extract Textures" button in the Find a CAS tab. However this will give you all the game textures linked to that mesh.

Quick Extraction

If you only need one or two files, instead of digging through all the textures, you can use the quick extraction method:

  • Anywhere you see a key number, click on it to highlight it then hit the "find" button nearest to the key. (Alternatively, you can double click the key).
  • A DDS preview window will come up, when it does click the "export" button at the bottom of the screen and choose a destination to save the file.

This also comes in handy when you need to retrieve a file you may have lost or deleted, simply open a preexisting package and follow the steps above.

Creation and Designing


These are extra actions found under File in the navibar.

Find Key

If you know the key number of a certain game texture, then you can type it in here and the CTU will retrieve it from the FullBuild2 package.

Generate Thumbnails

Generates all 1k+ thumbnails for faster loading.

Debug Mode

Debug mode shows some advanced buttons best left for more experienced simmers. While in Debug mode you can modify the TGI lists to change linkages to VPXYs, etc.

Sims 3 Root

By default the Sims 3 Root folder is located in C:\Program Files\Electronic Arts\The Sims 3. If your game is installed in a different location, you can change the path here.

3D Render View
By clicking the colored square, you can change the default background color of the 3D view window.


CAS Issues

CAS Part Not Showing Up At All

Make sure you:
(1) Have the game configured for .packages
(2) Installed the package in the correct directory.
CAS Part Won't Recolor
Some meshes are not recolourable and will simply not work at all in CAS. (i.e. the burglar gloves)
Wrong Thumbnails
Try deleting your caches.
Original Texture Won't Disappear
Sometimes no matter how many changes you've made to the base texture/specular you'll still see the original texture in CAS. What you're seeing is not the texture, but bumpmaps linked to the mesh.

CTU Errors

CAS Part Editor has stopped working....
Make sure you have DirectX Runtime installed or installed properly.
System.Core Error
Make sure you have .NET Framework 2.0 installed or installed properly.
Greyed-Out Mesh Parameters
If the mesh parameters are greyed out, and they won't let you change them make sure you hit File → New.
System.ArgumentOutOfRangeException Error
Change your Regional settings to make "." the decimal place separator instead of ",".

If All Else Fails...

If you've read the above FAQ and you still can't get the CTU working then go to the MTS CTU post to see if you can find an answer there.


Cheats, tips and tricks from user like you!

View .simgeom Files

Did you know that you can use the CTU to quickly preview .simgeom (mesh) files?

Here's what you do:

  • Right click on a .simgeom file and go to Open With
  • Click Choose default program
  • Click Browse, and browse to your CTU folder
  • Select the file called MadScience.Render.exe
  • Click OK a few times

Your .simgeom files are now associated with this tool and you'll find that when you double click on them, they now open up in the 3d rendering view used by CTU. The initial view is wireframe (since the .simgeoms have no texture) but it's very useful to quickly view a mesh to see what it is.

You can also setup your S3PE to automatically view .simgeom resources quickly and easily the same way if you edit Helpers.txt to do so.

Submitted by Delphy

Saving Packages

When editing a existing package(package made with CTU) If you make changes in the following tabs,

  • Part category
  • Stencil tool
  • Designs
  • Others(not 100%sure)

You can use save from the file menu to save your package.

If you make changes to the meshes tab(like updating your custom mesh) you MUST choose save as Choosing save will not load all necessary files into the package and make it corrupt.(and often crash your game).

Submitted by Base1980