There are other ways of obtaining 3D models online and once you do so, you can easily follow the 3D printing steps to generate your model.
Cadmapper is a web tool available and allows students to download up to 1 km for free.
Download desired size (more than 1 km requires you to purchase the model)
Save output format and open in Rhino
Location > Center To View (Red Box)
Adjust box size using slider ( Larger sizes will result in bigger files )
Vertical Scaling is to increase height of terrain (result of map will be inaccurate)
Exported terrain can be imported into Rhino.
The exported mesh will be problematic as it is an open mesh. A option is to upload the file to Netfabb to try and fix the open meshes.
This tutorial uses Elk version 0.3.1. You can download the latest version of the Elk plugin for grasshopper.
Elk can use a variety of datasets which are all derived from the Shuttle Radar Topography Mission.
This is the most basic and accessible and open version of the data and will be used for the rest of this tutorial. The data can be accessed through this data portal:
Refer to a mapping service that can give you a latitude/longitude range. OpenStreetMap (depicted below) is one such option to reference a range.
Referring to this coordinate range, download the corresponding range from the .hgt data portal.
High resolution files .IMG are available for the US using the USGS TNM Download portal.
.GEOTIFF files are available from the Earth Explorer portal.
In Grasshopper, load the file in using a File Path parameter by right-clicking the parameter and selecting Set One File Path. Navigate to the file's location and open it.
Plug the File Path parameter into Elk's SRTMTopo component.
Reference the Latitude and Longitude range of interest using a Construct Domain Component. In this example the OpenStreetMap data from before is used.
Right-Click on the
[S] of the
[SRTMTopo] Component and click
[Bake] to export the surface geometry into rhino.
In Rhino, extrude the surface
[ExtrudeSrf] thicken the surface and trim the base into a flat one for 3d printing using one of the many boolean operations.
The geometry is now ready to be meshed as per the 3d Printing Guidelines.