Direct generation of STL files from USGS DEM data for additive manufacturing of terrain models

Geographical information system (GIS) data in digital elevation model (DEM) format contains surface data of terrain on the Earth. This surface data needs to be converted into a 3D faceted file before uploading to an additive manufacturing (AM) machine. Commercially available software packages perform this task indirectly by translating and modifying data through different file formats. This paper discusses a methodology to convert the United States Geological Survey (USGS) 7.5-minute and 1-degree DEM file formats directly to 3D stereolithography (STL) ASCII format. A software program in C is developed to create a base and walls around the surface data to make a 3D STL part of the terrain. The STL file was uploaded to an AM machine (EOSP395) to fabricate a physical scale model of the terrain. This work not only removes intermediate steps and the associated data loss but can generate an STL part in relatively less time.