Blender Sims 4 GEOM Tools

A Blender add-on for importing and exporting Sims 4 SimGeom (.simgeom) mesh files.

📥 Download Latest Release - Click to download the addon zip file

This is a fork of SmugTomato's Blender Sims 3 GEOM Tools, updated to support The Sims 4 GEOM format.

Features

Import

• Import directly from .package files - No need for S4PE or other extraction tools!
• Import Sims 4 SimGeom files (.simgeom)
• Auto-create materials - Automatically extracts and applies textures from packages
• Import highest LOD only - Option to skip lower quality LOD meshes
• Custom normals support - Preserves original mesh normals
• Multiple UV channels - Supports meshes with multiple UV maps
• Vertex colors - Imports vertex color data (TagValue)
• Bone weights - Full vertex group and weight support
• Morph support - Import morph GEOMs

Export

• Export Sims 4 SimGeom files (.simgeom)
• Export RLE textures to DDS - Batch extract all textures from a package file
• Morph export - Export morphs linked to base meshes

Compatibility

• Blender 4.0+ / 5.0 compatible
• No external dependencies - Pure Python, no pip installs required

Supported Sims 4 GEOM Versions

• GEOM Version 12, 13, 14, 15 (RCOL wrapper v3)
• UVStitch, SeamStitch, and SlotrayIntersection data sections

Installation

⚠️ Do NOT clone this repo - Download the release zip instead!

1. Download the latest release (sims4-geom-tools-vX.X.X.zip)
2. In Blender, go to Edit > Preferences > Add-ons
3. Click Install and select the downloaded zip file
4. Enable the add-on by checking the box next to "Import-Export: Sims 4 GEOM Tools"
5. Press N in the 3D View to open the sidebar - look for the Sims 4 tab

Usage

Importing from a Package File (Recommended)

The easiest way to get meshes - import directly from .package files:

1. File > Import > Sims 4 Package (.package)
2. Select your .package file (CC mod, extracted game files, etc.)
3. Configure import options:
   • Choose Rig - Select a rig to import alongside the meshes
   • Preserve Normals - Import original normals as custom split normals
   • Import All LODs - Check to import all LOD versions, uncheck for highest quality only
   • Import Materials - Auto-create materials from textures in the package
4. Click Import

This supports both compressed and uncompressed package files - no external tools needed!

Importing a Standalone GEOM

If you have an extracted .simgeom file:

1. File > Import > Sims 4 GEOM (.simgeom)
2. Select your .simgeom file
3. Optionally select a rig to import alongside the mesh

Exporting a GEOM

1. Select your mesh object (must have the __S4_GEOM__ property)
2. File > Export > Sims 4 GEOM (.simgeom)
3. Choose your export location

Exporting Textures (RLE to DDS)

Extract all textures from a package file as standard DDS files:

1. File > Export > Sims 4 Textures (RLE → DDS)
2. Select a .package file
3. A dialog shows the texture counts found:
   • RLE2 - Diffuse/color textures
   • RLES - Specular/detail textures
   • DDS - Raw DDS textures
4. Choose which texture types to export
5. Select an output folder
6. Click OK to export

Exported files are named:

• diffuse_XXXXXXXXXXXXXXXX.dds - RLE2 textures
• specular_XXXXXXXXXXXXXXXX.dds - RLES textures
• texture_XXXXXXXXXXXXXXXX.dds - Raw DDS textures

Tools Panel

The add-on adds a panel in the 3D View sidebar (press N to open) under the SimGeom tab.

Available Tools

Tool	Description
Import Rig	Import a Sims 4 rig (.grannyrig)
Recalculate Vertex IDs	Renumbers vertex IDs starting from the specified start_id
Remove Vertex IDs	Removes vertex ID data from the mesh
Transfer GEOM Data	Copy GEOM properties from active object to selected objects
Rename Vertex Groups	Converts FNV32 hash names to readable bone names
Rebuild Bonehash Database	Updates the bone name lookup table from imported rigs
Make Morph	Create a morph from selected mesh linked to active mesh

Morphs

Morphs can be imported from GEOM morph meshes (extracted from BGEO files using tools like Cmar's S4PE plugins).

How Morphs Work

• Morphs are separate mesh objects linked to a base GEOM
• Each morph has a Morph Name and Linked to property
• When exporting, all morphs linked to the selected GEOM will be exported as separate morph files
• Morphs support custom normals just like base meshes

Importing Morphs

1. Select your base GEOM mesh
2. File > Import > Sims 4 Morph (.simgeom)
3. Select one or more morph .simgeom files

Materials & Textures

When importing from .package files with Import Materials enabled:

• The addon automatically finds all textures in the package
• Textures are converted from Sims 4's RLE format to standard DDS
• A separate material is created for EACH diffuse texture (e.g., Diffuse_1_XXXXXXXX, Diffuse_2_XXXXXXXX)
• Each material includes:
  • Diffuse (RLE2) → Base Color input
  • Specular (RLES) → Specular IOR Level input (shared across all materials)
• All materials are added to the mesh's material slots - switch between them using Blender's material dropdown
• Textures are saved to a temporary folder and loaded into Blender

This makes it easy to preview different texture variations (recolors) by simply selecting a different material from the dropdown.

Texture Types

Type	Format ID	Description
RLE2	0x3453CF95	Diffuse/color maps (DXT5 compressed)
RLES	0xBA856C78	Specular/normal maps (DXT5 compressed)
DDS	0x00B2D882	Raw DDS textures

Splitting UV Seams

This is an important step for proper mesh editing:

1. Open the UV Editor
2. Go to UV > Seams from Islands
3. In the 3D View with Edge Select mode active
4. Select an edge marked as a seam (orange)
5. Go to Select > Select Similar > Seam
6. Press V to split the seams
7. Recalculate Vertex IDs if your mesh uses them

Vertex IDs

• start_id - The vertex ID to start renumbering at
• The panel shows the highest vertex ID and unique ID count
• Don't modify these if you're not adding/removing vertices (preserves original IDs)
• Some items (like pet accessories) may not use vertex IDs

Transferring GEOM Data

To copy GEOM properties from one mesh to others:

1. Select the target meshes
2. Make the source GEOM mesh the active object (last selected)
3. Click Transfer GEOM Data in the panel

Fixing Bone Names

If vertex groups show as hex values like 0xef89a3e3:

1. Import the appropriate rig for your mesh
2. Select the rig and click Rebuild Bonehash Database
3. Select your mesh and click Rename Vertex Groups

This only needs to be done once - bone names are saved to a JSON file.

Technical Details

Package (DBPF) Format

The addon includes a full Python implementation of EA's DBPF package format:

• DBPF Version 2.1 - Standard Sims 4 package format
• Compression Support:
  • DEFLATE/zlib (standard compression)
  • RefPack (legacy EA compression)
• Resource Types:
  • GEOM meshes (0x015A1849)
  • DDS textures (0x00B2D882)
  • RLE2 textures (0x3453CF95)
  • RLES textures (0xBA856C78)

Sims 4 GEOM Format

• RCOL Wrapper: Version 3 with ITG (Instance-Type-Group) ordering
• GEOM Chunk: Version 12-15
• MTNF Shader Data: Embedded material/texture references
• Vertex Data: 9-byte format entries (usage, datatype, size)
• Weights: Stored as bytes (0-255) normalized to floats
• Additional Sections: UVStitch, SeamStitch, SlotrayIntersection

Supported Vertex Formats

Usage	Type	Description
1	Position	3 floats (X, Y, Z)
2	Normal	3 floats
3	UV	2 floats per channel
4	Bone Assignment	4 bytes
5	Weights	4 bytes (0-255)
6	Tangent	3 floats
7	Color/TagValue	4 bytes (ARGB)
10	Vertex ID	1 uint32

RLE Texture Format

The addon includes a pure Python RLE decompressor:

• RLE2 (0x32454C52): Standard diffuse textures
• RLES (0x53454C52): Specular textures with extra channel
• Converts to DXT5-compressed DDS format
• Supports all mipmap levels

File Menu Reference

Import Menu (File > Import)

Option	Description
Sims 4 Package (.package)	Import GEOMs directly from package files
Sims 4 GEOM (.simgeom)	Import standalone GEOM files
Sims 4 Morph (.simgeom)	Import morph GEOM files
Sims 4 Rig (.grannyrig)	Import skeleton/rig files

Export Menu (File > Export)

Option	Description
Sims 4 GEOM (.simgeom)	Export mesh as GEOM file
Sims 4 Textures (RLE → DDS)	Extract textures from package to DDS

Reporting Bugs

If you encounter any issues, please include the console output when reporting:

How to Open the Console

Windows:

1. Go to Window > Toggle System Console
2. A black console window will appear showing debug output

macOS:

1. Open Terminal app
2. Navigate to Blender: /Applications/Blender.app/Contents/MacOS/Blender
3. Run Blender from Terminal to see console output

Linux:

1. Run Blender from a terminal window
2. Console output appears in the terminal

What to Include in Bug Reports

1. Full console output - Copy everything from the console after the error occurs
2. Blender version (Help > About Blender)
3. Operating system
4. Steps to reproduce the issue
5. The .package file (if possible) that caused the error

The console shows detailed debug info like:

• GEOM version and structure details
• Texture conversion progress
• Specific error messages and line numbers

Credits

• SmugTomato - Original Sims 3 GEOM Tools
• cmomoney - Original rig importer
• blancodagoat - Sims 4 adaptation

License

This project is licensed under the GPL-3.0 License - see the LICENSE file for details.

Links

• GitHub: https://github.com/blancodagoat/blender-sims4-geom
• Original Sims 3 Version: https://github.com/SmugTomato/blender-sims3-geom