Files with the SPT extension are used by the CAD software called SpeedTree. An SPT file is used to store 3D data. It is a graphic containing a tree or possibly other plants. In addition, the file contains data related to the level of detail (LOD) of a given object as well as information related to animation and wind.

SpeedTree is tree modeling software developed by Interactive Data Visualization, Inc. SPT files can also be opened by other programs like 3D using SpeedTreeMAX or SpeedTreeMAYA plugins.