3D Printing Terrain
There are two methods I suggest for printing 3D terrain models: first is an easy method using an app, and the other is using your own Digital Elevation Model in ArcScene.
Meshlab (this is another free editing tool, less oriented for printing and more towards making digital 3D models, but very useful for converting between file types).
ArcScene (for the complicated method - this software is, alas, not free but is part of a typical ESRI ArcMap license)
First: The REALLY Simple Method
Here we will select an area for our terrain model. Zoom to a place you want to map or enter your desired latitude/longitude in those fields.
You can then place a box which will be your terrain .stl file. There is no way to change the shape of the box, but we can trim the result later on. The box can be moved/adjusted for size.
Put 2 in the first blank for water drop, and zero in the second for base height (this is a suggestion, default usually works okay too).
Then take a screen shot of your selected place – if you hit the alt key with print screen it will just take a photo of your active window. You can then paste this in a word doc or other program for reference. This will be a reference to orient your final product.
When you have it set how you like, hit Create STL File and then DOWNLOAD. An stl file is a file that can be 3D printed. STL has several after-the-fact backronyms (because it didn’t initially stand for anything) such as "Standard Triangle Language" and "Standard Tessellation Language".
Then SAVE FILE. The .stl file will then wind up in your download folder.
The Not As Simple Method: 3D Printing with ArcScene
For this method, you will need a DEM of the area you want to print, access to ArcScene, and access to software that can open a .wrl file and save it as an .stl file – I recommend Meshlab.
First, fire up ArcScene and add your DEM to the project.
Then we set the elevation.
Right click on the layer and go to Properties -> Base Heights. Set the base height to match the DEM, “Floating on a custom surface” with the file set to your DEM.
This may not give us a result which is terribly “hilly.” Even very mountainous areas are often flat seeming. So it may be desirable to enhance the hills to see the pattern of the terrain.
Right click on Scene layers -> Properties, and then adjust the Vertical Exaggeration. Usually 1 or 1.5 is adequate.
Now we are going to save the file as a .wrl, File -> Export Scene -> 3D, save it as .wrl
Unfortunately, the file type we need is an .stl file type and ArcScene does not export this. However, this .wrl file can be turned into an .stl file using various software. The one that I recommend is Meshlab. Meshlab is free. All you will need to do with the vrml .wrl file is open it in Meshlab, and then export the mesh as a .stl whereupon you will have a .stl file which can then be edited for printing.
To do this, download and install Meshlab from here: http://meshlab.sourceforge.net/
Then open MeshLab, go to File -> Import Mesh and open your .wrl file. Then go to File -> Export Mesh As… and save it as an .stl file.
Now you have an .stl you can edit.
To edit your .stl I recommend Autocad 123D Design and Meshmixer, both of which are free. 123D Design can be downloaded here: http://www.123dapp.com/design and Meshmixer can be downloaded here: http://www.meshmixer.com/download.html
Note: 123D Design often makes it seem like you need to login to Autodesk's login system, but you do not. Just click tabs away from the login request or close windows and you will not need to login to an account (this may change in the future).
You will need to do two things to make your 3D model printable – shrink it and make it “watertight” closing any gaps in the model. To shrink it use 123D Design, to make it watertight use Meshmixer.
Open 123D Design.
First hit the edit grid page in the lower right and select inches (or whatever you like) as your unit of measurement.
Then open your .stl file: The left hand Autodesk button -> import file
The first thing to do is shrink the model to make it easier to work with. To do this: double click on the model and a tool bar should appear at the bottom of the screen. The second button from the left is Smart Scale, if you click it you can see how many inches your model is on a side and decide how far to shrink it. The third button is uniform scale. Clink on that button. You will want your model to be about 4 inches on a side for cheaper printing, and likely no more than 7 inches (depending on your printer). Using a decimal factor (to get a 324 inch model to be small enough I needed to use .01). Then you may need to use the rotate and move tool to reorient your model to the printing platform - this is the first button, you can "grab" the circle on the correct axis to adjust orientation.
After you get it to the size and orientation you want it, then save your file by File (Autodesk icon) -> Export -> 3D model.
Once you have your rough model exported, save and close 123D Design and open Meshmixer.
In Meshmixer you can “repair” and make your model water tight for printing.
Again, instead of Opening your file, Import it.
Loading the file may take some time.
Then go to “Print Model” and hit repair. The repair process may take a long time. After the repair process is finished, save the model again.
At this point, provided you have oriented the model to the platform correctly, you should be able to print it.