What is the SPT file format?
A .spt file is a legacy project file used by SpeedTree, the procedural vegetation modelling software developed by Interactive Data Visualization (IDV). It stores all parameters needed to define a 3D tree or plant: branch hierarchy, level-of-detail (LOD) stages, wind-animation settings, cloning data, texture references, and per-asset rendering properties.
IDV introduced SpeedTree around 2003, and .spt was the native project format through early SpeedTree Modeler and SpeedTree Architect releases. With SpeedTree 7 the native format shifted to .st, and SpeedTree 9 introduced .st9. Unity Technologies acquired IDV in July 2021. The current SpeedTree Modeler 10 (released September 2024) saves only .st or .st9; .spt is a legacy format no longer written by modern SpeedTree releases.
Export targets such as FBX, OBJ, USD, and STSDK are used for delivering vegetation assets to game engines and DCC tools - there is no direct .spt conversion path in SpeedTree 10.
The format is proprietary binary with no public specification, no confirmed magic-byte signature, and no documented internal compression. Older builds of SpeedTree Modeler and the SpeedTree plugins for Autodesk Maya and 3ds Max can open .spt files.
Security & safety
RISK: LOWSPT is a 3D model data file and poses no execution risk. It is processed only by SpeedTree Modeler and compatible plugin integrations. Download model files only from reputable sources (official SpeedTree library, trusted 3D asset stores) to avoid receiving malformed or malicious project files.
Format details
in a nutshell- Script or configuration files - .spt is also used by various unrelated scripts and configuration files in different software ecosystems - context distinguishes them.
Programs that open SPT files
Windows3 apps
SpeedTree Modeler
Paid File > Open to load the .spt file. Subscription-based; free trial available from unity.com/products/speedtree.
Autodesk Maya (with SpeedTree plugin)
Paid Install the official SpeedTree plugin for Maya; use it to import .spt vegetation assets into Maya scenes.
Autodesk 3ds Max (with SpeedTree plugin)
Paid Install the SpeedTree plugin for 3ds Max to import .spt assets. 
macOS1 app
Linux1 app
Technical details
deep spec| Format type | Proprietary binary 3D vegetation model project file |
| Encoding | Binary, little-endian (Windows-native origin) |
| Container | Proprietary SpeedTree project container (no public specification) |
| Compression | Unspecified - no public format documentation |
| Typical file size | 100 KB - 50 MB depending on tree complexity and embedded textures |
| Stored data | Branch geometry parameters, LOD stages, wind animation, texture references, rendering properties |
| LOD stages | Multiple per-asset LOD levels for real-time rendering performance |
| Wind simulation | Per-branch and per-leaf wind parameters baked into the file |
| Format era | Legacy pre-SpeedTree v7 (circa 2003 - ~2014) |
| Successor formats | .st (SpeedTree v7+) and .st9 (SpeedTree v9+); current tool is SpeedTree Modeler 10 (2024) |
| Developer | Interactive Data Visualization (IDV); Unity Technologies acquired IDV in July 2021 |
| Platform | Windows, macOS, Linux (SpeedTree Modeler) |
| DCC integration | Autodesk Maya and 3ds Max via SpeedTree plugin |
| Released | circa 2003 (SpeedTree Architect early releases) |
| Latest version | .spt is a legacy format; current SpeedTree Modeler 10 uses .st / .st9 |
| Specification | docs.unity3d.com |
SPT conversions
Community Q&A
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