| name | mesh-converter |
| description | Guide for using the meshconvert command-line tool to convert Wavefront OBJ files to DirectX runtime formats (CMO, SDKMESH, VBO). |
| license | MIT |
| metadata | {"author":"chuckw","version":"1.0"} |
Mesh Converter Skill
This skill provides guidance for using the meshconvert command-line tool to convert Wavefront OBJ geometry files into runtime formats consumed by DirectX Tool Kit.
When to Use
Invoke this skill when:
- Converting Wavefront OBJ files to SDKMESH, CMO, or VBO format.
- Preparing mesh geometry for use with DirectX Tool Kit (DirectXTK).
- Generating normals, tangents, or performing vertex-cache optimization on mesh data.
- Understanding the available output formats and their requirements.
Overview
The meshconvert tool imports geometry from Wavefront Object (OBJ) or VBO files and prepares it for runtime use. It can generate normals and tangent frames, perform vertex-cache optimization, and write to formats suited for DirectX applications.
Installation
winget (Recommended)
winget install Microsoft.DirectX.Mesh
vcpkg
vcpkg install directxmesh[tools]
Basic Syntax
meshconvert [options] [--file-list <filename>] <file-name(s)>
The tool uses Windows-style - or / for options, and also supports GNU long options with --.
Output Formats
| Format | Switch | Description | Requirements |
|---|
| SDKMESH | -ft sdkmesh | Default output format for DirectX Tool Kit Model class | None |
| SDKMESH (PBR) | -ft sdkmesh2 | SDKMESH with PBR materials | None |
| CMO | -ft cmo | Visual Studio CMO format for DirectX Tool Kit Model class | Normals, tangents, and texture coordinates |
| VBO | -ft vbo | Simple vertex buffer object format for DirectX Tool Kit | Normals and texture coordinates |
| OBJ | -ft obj | Re-export as Wavefront OBJ | None |
Common Workflows
Basic Conversion to SDKMESH (Default)
meshconvert model.obj
Produces model.sdkmesh with no additional processing.
Convert with Normals and Optimization
meshconvert model.obj -n -op
Generates normals (weight by angle) and performs vertex-cache optimization using the Hoppe algorithm.
Convert to CMO Format
CMO format requires normals, tangents, and texture coordinates:
meshconvert model.obj -ft cmo -n -tb
Convert to VBO Format
VBO format requires normals and texture coordinates:
meshconvert model.obj -ft vbo -n
Convert with Full Processing Pipeline
meshconvert model.obj -n -tb -op -y
Generates normals, tangent frames (tangents and bi-tangents), optimizes the vertex cache, and overwrites any existing output file.
Convert for Direct3D Coordinate System
OBJ files from tools using OpenGL conventions may need coordinate adjustments:
meshconvert model.obj -n -op --flip-v --flip-z
Flips the V texture coordinate and negates Z for right-hand to left-hand conversion.
Batch Conversion
meshconvert -r *.obj -n -op -y
Recursively processes all OBJ files in the current directory and subdirectories.
Or use a file list:
meshconvert --file-list models.txt -n -op -y
Where models.txt contains one filename per line (lines starting with # are comments).
Option Reference
See reference/options.md for the complete command-line options reference.
Format-Specific Notes
SDKMESH
- Default output format.
- Supports 16-bit and 32-bit index buffers (auto-selects 16-bit when possible).
- Supports configurable vertex formats for normals, UVs, and colors.
- Used by DirectX Tool Kit's
Model class via Model::CreateFromSDKMESH.
CMO
- Visual Studio's mesh format.
- Requires normals, tangents, and texture coordinates — use
-n -tb switches.
- Fixed vertex format (no
-fn, -fuv, -fc, or -ib32 options).
- Used by DirectX Tool Kit's
Model class via Model::CreateFromCMO.
VBO
- Simple binary format with position, normal, and texture coordinates.
- Requires normals and texture coordinates — use
-n switch.
- Fixed vertex format (no
-fn, -fuv, -fc, or -ib32 options).
- Limited to 65535 vertices (16-bit indices only).
- Used by DirectX Tool Kit's
Model class via Model::CreateFromVBO.
Key References
