What is the SKM file format?
An .skm file is a SketchUp Material File - a self-contained material and texture package used by SketchUp's material library system. Despite its dedicated extension, the file is a standard ZIP archive under the hood: renaming .skm to .zip and opening it with any archive tool reveals the internal layout immediately.
Inside the package you will typically find:
- A material XML descriptor defining surface color, opacity, shininess, and texture mapping parameters
- An embedded texture image stored as a JPEG or PNG
- A small thumbnail
.pngused as the preview in SketchUp's Materials panel
The format is developed and maintained by Trimble (formerly @Last Software, then Google) and has been the standard material-packaging format since approximately SketchUp 8. It is important to note that .skm stores only surface appearance data - geometry and scene structure live in the separate SketchUp model (.skp). Third-party archive tools such as 7-Zip can inspect the internal XML and textures, but cannot apply the material to a scene.
Material files can be imported and exported via SketchUp Pro on Windows and macOS, SketchUp for iPad, and the browser-based SketchUp Free. File sizes typically range from 10 KB to several megabytes, driven by the resolution of the embedded texture image.
Security & safety
RISK: LOWAn .skm is passive data (a ZIP of an image and XML) and cannot execute. The only cautions are general ZIP hygiene: download material packs from reputable SketchUp sources (3D Warehouse, well-known resource sites) and scan archives from unknown origins, since any ZIP can be a wrapper for unrelated files. Avoid look-alike "free SketchUp download" sites - get SketchUp from sketchup.com.
Format details
in a nutshell- SSEYO Koan Music file - Older generative-music project file from SSEYO Koan (Tao Group); unrelated to SketchUp and effectively obsolete.
- ScanMaster / instrument data exports - A few measurement and scanner tools have written .skm data files; niche and vendor-specific.
Programs that open SKM files
Windows3 apps
7-Zip
Open-source Rename .skm to .zip (or open directly) to extract the texture image and XML - for inspection, not for using the material in SketchUp. 
SketchUp (Pro / desktop)
Paid Open the Materials panel, expand it, use the import/details menu to load the .skm, or drop the file into SketchUp's Materials folder so it shows in your library.
SketchUp Free (web)
Freemium Sign in to the browser app and import the material via the Materials tray (texture import support varies by tier). 
macOS2 apps
SketchUp (Pro / desktop)
Paid Use the Materials panel to import the .skm, or place it in your SketchUp Materials collection folder. Technical details
deep spec| Container format | ZIP archive; magic bytes `50 4B 03 04` ("PK") at offset 0 |
| Internal layout | Material XML descriptor + texture image (JPG/PNG) + thumbnail PNG preview |
| XML descriptor content | Defines surface color, opacity, shininess, reflectivity, and UV texture mapping (scale, offset, rotation) |
| Compression | DEFLATE per-entry compression (standard ZIP); embedded JPEG/PNG files carry their own internal compression |
| Byte order | Little-endian, inheriting the ZIP specification |
| Typical file size | 10 KB - 5 MB, driven by the resolution of the embedded texture image |
| Texture color depth | 8 bits per channel; 24-bit RGB (JPEG) or 32-bit RGBA (PNG) for alpha-transparent materials |
| Texture tile dimensions | Commonly 128 × 128 px to 2048 × 2048 px; SketchUp scales the tile to cover model surfaces |
| Integrity checking | ZIP per-entry CRC-32 checksum; no whole-file cryptographic signature |
| MIME type | `application/octet-stream` (canonical); also recognized as `application/zip` by generic tools |
| Platform support | Windows, macOS, iPadOS (SketchUp for iPad), Web (SketchUp Free) |
| Encryption | None - ZIP entries are stored unencrypted and fully readable by any archive tool |
| Stores geometry | No - surface appearance data only; 3D geometry resides in the separate `.skp` model file |
| Material schema versioning | XML schema version is stamped by the creating SketchUp release; newer schemas may require a matching or newer SketchUp version |
| Typical internal file count | 3-5 files per archive (XML + texture image + thumbnail PNG); ZIP specification allows up to 65,535 entries |
| Released | SketchUp 8 era (material library packaging, c. 2010) |
| Latest version | SKM v2 schema (current SketchUp 2017-2025 materials) |
| Specification | developer.sketchup.com |
SKM conversions
Community Q&A
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