Guide to Using the STL Generator Plugin

These instructions will explain the necessary steps for creating a stereolithography (STL) file representing the terrain of your country of choice. This manual will cover how to download Digital Elevation Models (DEMs) representing the country's terrain, merge those downloaded DEM files, and then turn that cropped DEM into an STL file. It is recommended that you have some knowledge about the printing capabilities of your 3D printer. Some of the later steps will require you to put in parameters that are the dependent on your printer settings such as your line width or layer height.

Installing The Files and Software

Downloading The Necessary DEM Files

The first step towards generating a 3D model of your terrain is downloading the elevation models. While there are many places you could download elevation models from, for the sake of this guide, we'll be using OpenTopography. If you already have your DEM files, you can skip down to "Preaparing The DEM Files". Now, these are the steps you will need to take for downloading these Digital Elevation Models (DEMs):

  1. Go to the OpenTopography website
  2. Click on “List all Datasets” and then scroll down and select “Global & Regional DEM”
  3. You should see a list of dataset names pop up right underneath the button you just clicked. On the 9th row, find the button that says “SRTM GL3” and click on it. This will take you to a new webpage for downloading DEMs from the SRTM GL3 dataset.
    4. Figure 1: OpenTopography webpage showing the “List All Datasets” hyperlink (top left), “Global &Regional DEM” tab, and the button for the “SRTM GL3” dataset
  4. Once on the new page, scroll down until you see the map widget and click on the “Select A Region” button in the top-left corner of the map.
  5. Highlight your region of interest on the map by pressing down left-click at the top left corner of the region and releasing left-click at the bottom-right corner of the region
    1. A region that has been successfully selected will be highlighted by a light blue rectangle as shown in figure 2.
    6. Figure 2: Image of map widget(top) with a region selected in blue
  6. Scroll down to the section labeled “Job Description” and enter your e-mail address in the corresponding section below.
    7. Figure 3: Job description section with an example email entered in the bottom text box
  7. Click submit to finalize the download request. This will take you to a new page where you will have to wait for your download to be processed. This may take a few minutes.
  8. Once the job status changes to done, you will find a download link appear under the “Download Data” section. Click on this link and you will be able to download the DEMs needed for this
  9. Extract the downloaded zip file and move the extracted “.tif” file into its own folder
    1. a. If you must download files in multiple stages, save all the DEMs into this same folder as it will make the future steps easier

Preparing the DEM Files

Opening the DEMs in QGIS

  1. At the top navbar, go to Layer > Add Layer > Add Raster Layer. This will open a new popup window.
  2. Underneath the “Source” section, click the horizontal ellipses button to open the file explorer as seen in figure 4.
    3. Figure 4: Popup window where you select the DEMs to be opened. The horizontal ellipses can be seen to the top right.
  3. Navigate to the folder you downloaded your DEMs, select all the DEM files you downloaded previously, and then press enter.
  4. Click Add at the bottom of the popup window
  5. Close the popup window.

(Optional) Combining the DEMs

*** This section is only necessary if you downloaded multiple DEM files and you want to use them together to generate a model

  1. At the top navbar, go to Raster > Miscellaneous > Merge… which will open a new popup window.
  2. Click on the horizontal ellipses button which opens up a window showing all your DEM files.
  3. Click on the “Select All” button and double check that all of the listed DEMs have a checkmark beside them.
  4. Finally, click on “Run” at the bottom of the window and wait for the merge to finish processing.
  5. Once it's done running, you can close the popup window.

Using the STL Generator Plugin

Installing the Plugin

  1. At the top navbar, go to Plugins > Manage and Install Plugins…
  2. In the newly opened window, type “STL Generator” in the top search bar.
  3. Click on the name “STL Generator” in the list to the left side of the window.
  4. Click on the “Install Plugin” button at the bottom of the window.
  5. Once the plugin is finished installing, you can close the popup window

Creating an STL using the Plugin

Now all that's left is to turn the DEM that you finished processing in the previous steps into a 3D STL file.

Figure 5: Dialog window for STL Generator plugin
  1. At the top navbar, go to "Raster" > "STLGenerator" > "Generate an STL File", which will open a new popup window.
  2. In the dropdown box under “Layer to Print”, select the layer that you want to make an STL out of.
    1. If you followed the steps for preparing the DEM files above, select the one layer you have if you only had one DEM file or select the layer named “Merged” if you had to merge multiple files.
  3. Next, go to the "Model Settings" section below and enter the Model Height and Base Thickness in millimeters
    1. Model Height refers to the distance between the highest and lowest point of the DEM. Increasing this value will lead to more exaggerated highs and lows on the model
    2. Base Thickness refers to the the distance between the lowest point of the DEM and the bottom of the model. Increasing this value will increase the thickness of the model without affecting the terrain on top of the model.
  4. Under the "Printer Settings" section, fill out all the parameters with the corresponding settings from you 3D printer and slicer
  5. For the "File Location", enter the directory/folder you want to save the file to, using either the text box or by clicking on the three dots and using the file explorer
  6. Finally, click on "Export to STL" and select where you want to save your STL file.

You're Done!

Congrats, you now have a completed STL file representing the terrain of your choice. Now, you can use this STL to get started on 3D printing a physical model of the region. You can use this 3D print for an educational model, decorative piece, or anything else you want. You can even share this file with others you know or on the internet, so they can 3D print their own model too. While this guide focused on the final goal of 3D printing your model, you can still use this STL for purposes other than 3D printing such as in computer-aided manufacturing or digital animations. Regardless of what you do, hopefully your newly generated model can help you continue to appreciate some of the incredible geography that our planet has to offer.