Introduction
In this workshop we will prepare digital terrain models for 3D printing using open source software. First we will load GRASS elevation rasters in QGIS. Then we will use the GQIS plugin DEMto3D to generate a stereolithography mesh (.stl) for 3D printing. We will check the STL mesh in MeshLab. Finally in Slic3r we will compute slices for 3D printing and and generate g-code instructions for 3D printing.
Sample Data
GRASS Location: Washington South State Plane Meters HARN (EPSG 2856)
Software
QGIS: a free and open source Geographic Information System (GIS) integrated with GRASS GIS
DEMto3D: 3D printing plugin for QGIS
MeshLab: Open source mesh processing, editing, and rendering
Slic3r: Open source g-code generation for 3D printing
Workflow
Launch QGIS 2.12 with GRASS 6
In the Plugins menu select Manage and Install Plugins.... Install, update, and check the GRASS 6 and DEMto3D plugins.
In the Browser Panel browse to your GRASS data directory, browse to a mapset, and open a raster elevation map.
In the Raster menu select DEMto3D and then DEM 3D Printing.
In the DEM 3D Printing dialog set "Layer to Print" to your raster elevation map. Either set "Print extent" to "Select layer extent" or draw an extent. In "model size" first set the spacing to 0.2 mm. Then set the width and height of the model to build dimensions of your 3D printer (for example 100 mm x 100 mm). Then if possible set a good map scale without exceeding the build dimensions of your 3D printer. Set a vertical exaggeration factor if desired. Set the base height to the lowest point. Export to STL.
Launch MeshLab
Import the STL. If neccessary use the tools in the Edit and Filters menus to fix the mesh.
Launch Slic3r
In the Plater tab select Add... to load your STL file.
In the Print Settings, Filament Settings, and Printer Settings tabs set parameters for your 3D printer.
Check the slices using the Preview tab at the bottom of the screen. Preview mode renders what the printed model and its support structure should look like. In preview mode use the slider to move a cutting pane and view each slice.
Select Export G-code to generate instructions for your 3D printer.