3D printing and geospatial technologies are gaining more accessibility and popularity. When used together, 3D maps can be created to communicate planned or existing terrain or just have fun. The instructions listed below outline steps for acquiring 3D spatial data, options for processing it in Global Mapper, and exporting it as a file that’s digestible by your slicer.
Global Mapper is a GIS software with a reputation for its ability to handle large terrain and 3D files and export them to just about any file type. Version 25.1 introduces a tailored STL exporter for generating slicer-ready data. This new feature takes advantage of Global Mapper’s extensive terrain handling tools to create STL files at the proper horizontal and vertical scale, with options for extruding a base and sidewalls.
Step 1. Load the Data into Global Mapper
Already have data? Great! It’s easy to load into Global Mapper. Either drag and drop it into the workspace or go to File > Open. Global Mapper can handle just about any spatial file type. The most common for 3D GIS data will be a GeoTIFF or .las/laz.
While the exported .stl file won’t include color attributes, in Global Mapper, you can choose different visualization options to help during editing. The elevation shader is a dropdown menu in the Viewer toolbar that applies color to raster data based on elevation. To see the data as an all-white layer, mimicking a solid color filament print, choose the Daylight Shader.
Crop
The raster data can be cropped to fit into a polygon/area feature. You can draw an area feature using the digitizer tool, as demonstrated here. Cropped data isn’t deleted; it can be brought back by changing the settings, but cropped data isn’t included in the export. Here is a video demonstration on cropping raster data.
Terrain Paint
Are there parts of the terrain you would like to change? The Terrain Paint tool can do just that. Terrain Painting tool allows for the manual manipulation of terrain by using the cursor like a brush to paint and edit the elevation surface in various ways. Read more in this blog: How to use the new Terrain Painting tool in Global Mapper Pro.
Generating 3D Data from Drone-Collected Imagery
Pixels to Points is a photogrammetric tool that can create 3D mesh, point clouds, and orthoimages from overlapping aerial imagery. Use this to print a 3D model of your own house! Read more about getting started with 3D drone mapping in this blog: Got a Drone? Now What? — Using Global Mapper with Your UAV.
Step 2. Export as an STL
To export your data, from the file menu, choose Export > Export 3D Format and choose STL (3D Printing). Other 3D file formats are also supported by Global Mapper, but this STL exporter properly scales the data to a cm/mm/in scale. Typically, when data is exported from a GIS, its scale is maintained. That’s the primary use of a GIS. Typical 3D printers aren’t yet printing at the landscape scale, so the ability to scale the data down to the size of a standard print bed is useful.
Print Dimensions:
The default value for this horizontal dimension is set to the data’s current real-world extent. Unless you’re using the world’s largest printer, scale this down to fit within the 3D print bed. Leave the Preserve Horizontal Aspect Ratio option enabled to prevent warping.
Z Scalar (Exaggeration):
The Z Scalar setting allows you to exaggerate the height of the model. This can be especially useful with data in relatively flat areas. The Z Scalar variable is very similar to the Vertical Exaggeration setting in the 3D Viewer, a tool that’s great to use for visualizing the desired exaggeration. Change this value in the 3D viewer from the Configuration menu by clicking the Wrench icon > 3D View Properties > Environment > Vertical Exaggeration.
Swipe to see vertical exaggeration applied to this data in the 3D viewer.
Create a Base:
A base is a flat surface extruded from the bottom of the model. Check the Add base and walls extended below the lowest elevation option to automatically create a base during export, along with sidewalls to connect the base to the print.
You want the base to be lower than the lowest point in your print. The Base Thickness setting determines how far below the lowest point in the data the base will be extruded to. Setting this to 0 will create the base at the lowest point, which may create a hole or thin area in your 3D print depending on layer thickness, as shown in the image. We recommend at least 2mm for a strong base.
Sample Spacing:
A familiar concept to those who work in GIS is that the sample spacing is the grid cell size of the data. You can also think of it as the resolution. A higher resolution (a smaller number) will create a more detailed model at the cost of a larger file size. If you are scaling a large area down to fit onto a print bed, then a larger number (lower resolution) would be more practical. For example, when creating a model of the Grand Canyon, a 1m resolution would likely create details that are too small to appear in the final print. Setting the resolution to 100m or larger would be more practical for such a large area.
Click ok to export the data. The solid model can be viewed in Windows through the native viewer to make sure the base thickness and z exaggeration are what is expected. The file is now ready to be sliced and printed!
Have you created a fun or interesting print from Global Mapper? Tag us on social media! LinkedIn, Instagram, Facebook
If you would like to explore terrain editing and exporting in Global Mapper, download a 14-day free trial today! If you have any questions, please contact us.
Companies using Blue Marble’s geospatial technology