Merry Christmas, everyone!

Due to numerous issues related to existing tools for editing CAS parts, I decided to make my own.

Currently, it supports the following features:

• Editing part flags (e.g., age, gender, species, categories, etc.)
• Adding, editing, and deleting presets
• Importing/exporting GEOMs, OBJs, and WSOs
• Displaying morphs
• Changing the shaders and material properties of mesh groups
• Adding mesh groups to LODs
• Converting 3-pattern presets to 4-pattern ones

Support for the following is planned:

• Assigning morphs and bones (both of which in the meantime can be done in Meshing Toolkit)
• Creating patterns (this can be done in the meantime with Delphy's Pattern Packager)
• Displaying a full Sim in the viewport (partially implemented; still have to implement makeup and skin tone)
• Creating/editing CAS parts for The Sims Medieval

It's lightweight and runs on both Windows and Linux (macOS support planned). For Windows, .NET Framework 4.0 and GTK# 2.12 are required (check the download's instructions).

Do note that this tool has not been 100% tested due to scarcity of testers (the tool is very niche); please be patient and explain whatever issue there is to me.

Source code available here

Acknowledgements

Below is a list of people who helped with this project either directly or indirectly (as well as their contributions):

• Peter L. Jones – Provided the S3PI library which serves as the basis of this tool and many other Sims 3 tools
• CmarNYC – Her code for TS3SimRipper helped with applying patterns to textures and displaying morphs in the 3D renderer; the code for her Meshing Toolkit for importing/exporting OBJs and WSOs was also borrowed
• MonoChaos – Provided the icon for the tool and helped test the tool for issues
• zoeoe – Helped with issues related to the S3PI library and provided some code for object meshes
• VirtualHugs – Helped with explaining things related to CASPs; I'm not a mesher, so her advice was incredibly helpful

Testers:

• K'tar
• MonoChaos
• nectar-cellar

Changelog

• Hotfix #1 (2025/12/25) – Fixed several issues related to morphs
• Hotfix #2 (2025/12/26) – Removed unneeded dependencies
• Hotfix #3 (2025/12/26) – Fixed an issue in a dependency for reading resources to determine their types
• Hotfix #4 (2025/12/26) – Fixed resources not being detected as XMLs when being imported (though one should not import XMLs anyway as of this update)
• Hotfix #5 (2025/12/26) – Fixed a crash upon changing texture resource keys in material properties for meshes
• Hotfix #6 (2025/12/27) – Fixed a crash upon loading certain meshes due to invalid vertex IDs
• Hotfix #7 (2025/12/27) – Added some logging for crashes
• Hotfix #8 (2025/12/27) – Fixed locale differences causing crashes
• Hotfix #9 (2025/12/27) – Changed the archives to RAR format because the default Windows ZIP extractor is faulty
• Hotfix #10 (2025/12/28) – Fixed a crash that would happen when keys in the preset XMLs were not in the right case
• Hotfix #11 (2025/12/28) – Fixed an issue where thumbnails would not show for default values of some presets due to the values being paths instead of keys
• Hotfix #12 (2025/12/28) – Added more rigorous logging
• Hotfix #13 (2025/12/29) – Fixed the preset panel extending beyond 50% of the width of the window; as an unfortunate consequence, the new preset button is now to the left of the preset tab bar
• Hotfix #14 (2025/12/29) – Fixed crashes for certain LOD meshes due to incomplete vertex ID data for morphs
• Feature Update #1 (2025/12/30) – Added the ability to convert 3-pattern presets to 4-pattern ones.
• Hotfix #15 (2025/12/30) – Fixed a crash when loading certain patterns and another crash when importing OBJ and WSO meshes with incomplete vertex ID data
• Hotfix #16 (2025/12/31) – Restructured the code base
• Hotfix #17 (2026/01/02)
  • Removed the broken sorter for patterns in the tab list
  • Made panels resizable
  • Packages can now be opened with this program using "Open With" or by dragging the package onto the executable
• Hotfix #18 (2026/01/03) – Added descriptions to the executable and DLLs so that they would not appear blank in the "Open With" list
• Hotfix #19 (2026/01/04)
  • Fixed a bug where adding a mesh group to an LOD would insert it at the wrong index
  • Moved more logic to libraries
• Hotfix #20 (2026/01/04) – Fixed "start.sh" on Linux trying to launch a nonexistent executable
• Hotfix #21 (2026/01/06)
  • Fixed scaling of non-square textures in the image viewer
  • Partitioned the code base even more
• Hotfix #22 (2026/01/07)
  • Fixed scaling on Linux for lower resolutions
  • Unified Linux downloads (figured out how to bundle it better)
• Hotfix #23 (2026/01/07) – Fixed "start.sh" for Linux to allow for arguments
• Hotfix #24 (2026/01/09) – Uncapped decimal values for presets and patterns
• Hotfix #25 (2026/01/13) – Fixed an issue where Pattern D would not be displayed if it was loaded after the logo
• Hotfix #26 (2026/01/17) – Fixed the icon not showing for the executable on Windows
• Hotfix #27 (2026/01/17) – Fixed a crash upon adding a preset
• Hotfix #28 (2026/01/17) – Added previews for images in the image resource dropdowns
• Hotfix #29 (2026/01/18) – Fixed a crash on launch for Windows XP
• Hotfix #30 (2026/01/18) – Improved the performance for the image renderer on Unix-like systems
• Hotfix #31 (2026/01/18) – Fixed blending for RGB masks
• Hotfix #32 (2026/01/18) – Made it so that the application would unblock the DLLs if extracted by the default Windows archive extractor
• Hotfix #33 (2026/01/18) – Fixed duplicate shader names
• Hotfix #34 (2026/01/19) – Updated licenses and copyright notices
• Hotfix #35 (2026/01/19) – Fixed some potential bugs related to locale
• Hotfix #36 (2026/01/20) – Fixed some more potential bugs related to locale
• Hotfix #37 (2026/01/20) – Fixed a random crash caused by bitmaps being accessed by different threads simultaneously
• Feature Update #2 (2026/01/21)
  • Added the ability to reorder presets
  • Fixed the preview image not clearing when a package was closed
• Feature Update #3 (2026/02/07)
  • Added partial support for rendering a full Sim
  • Fixed multiple issues regarding mesh group imports
  • Changed morphs to be applied on the GPU side rather than the CPU side, thereby making it less laggy
  • Improved the dialog for setting the game folder paths
  • Fixed a crash when trying to load makeup