Do yourself a favour. Go to Google maps. Go to your favourite location. Press Ctrl, left click and drag around. Everthing gets all 3D! And if you’re are in Auckland, Christchurch or any of the cities on this list, you have a fully 3D modelled city. If you’re in the sticks or a much better city such as Hamilton, you only get terrain. Which is still pretty awesome.
Sadly, you can’t extract all this data for 3D modelling or 3D printing. Or can you? I spent hours trawling forums and google search results trying to find a way. I tried 3D screen capture software with names like 3D Ripper DX and GL Intercept (they only work on old versions of google earth). I was so desperate for clues that I even read the terms and conditions of a license agreement before ticking accept. I know. Finally I admitted defeat and settled for extracting terrain only, and not buildings. If you know how to get all the data, please get in touch.
This tutorial uses Sketch Up, a former Google product. Mainly due to my background in other modeling software, I find SketchUp quite hard to use. I only learn it for things I have to but their terrain import is really good (although not 100% accurate). Therefore this is the bare minimum of SketchUp knowledge to extract a model for 3D printing terrain.
Maybe you want to print off a farmer friends back block or “give” a friend a mountain you climbed together.
- Download and open SketchUp.
- Install the SketchUp STL plug in. This lets you export in the .STL format, which 3D printers can read. Go to Window, Extensions Warehouse and Sign In (important as it doesn’t work otherwise) then search for SketchUp STL and install it.
- Now we load the 3D terrain. In SketchUp select File, Geo-location, Add Location and navigate to the place that you want to 3D model. When you have decided on the region click “Select Region” (I had to make the window a bit larger than default for this button to reveal itself).
- Now there should be a flat plane with an image of your region on it. Go to File, Geo-location, Show Terrain to turn this into a terrain surface of your region. Hold down your middle mouse button and rotate to view the contours.
- Using the select tool (shortcut: space), left click the surface, then right click and select “Unlock”. This lets us modify the terrain surface.
Now we need to create our bounding geometry via a plane or a box. I use rectangular planes for things like mountains that have a well defined “bottom”, and box’s for general terrain that doesn’t have a well defined end. You can also use a “Shell” method to only print a thickened surface rather than a solid block, this can save lots of material (and therefore money on the printer).
Adding cut rectangle
- Double click the surface such that a black dotted box appears around the terrain surface. This lets us create geometry in the same “Group” as the Surface, which you don’t need to understand very well (I don’t) but a frustrated hour of forum reading tells me is important.
- Under Shapes in the ribbon menu select rectangle. Draw a rectangle that is bigger than your terrain surface. If the rectangle is not on the plane you want, try to draw it to a different location.
- Position the rectangle with the “move” tool (shortcut: m) so that it completely intersects the terrain at your desired altitude. The up, left and right arrow keys let you lock the movement into a single direction.
- Now we want to trim away the unnecessary surfaces. So that SketchUp “understands the boundary where the surfaces, we need to intersect the surfaces.Press space to select, double click either surface (this selects the whole group). Right-click either surface and select Intersect Faces, With Model.
- Now select and delete the outside surfaces and lines to trim them away.
- Unless you want to 3D print at a 1:1 scale, now is a good time to scale the Model. The Scale tool is one option, but in this case we need a large reduction so we can use the Tape Measure. Select “Tape Measure” in the ribbon menu then click at two ends of your model. You can now see the dimension of your model in the bottom right hand corner. Type the desired dimension that you want this to change to and when prompted if you want to resize the model, select Yes.
- Press “Shift + z” to zoom to your model. I had to change to “Parellel Projection” under the Camera menu to see my model because of a glitch.
Extruding and Exporting
- If the edges of your model aren’t steep, they can be thin and difficult to 3D print. In this case it can be a good idea to thicken the base of your model with an extrude. Select (shortcut: space) the bottom surface of your model and click extrude. Drag the bottom surface, then type the exact distance you want to add (2mm is typically OK).
- Now you are ready to export the model! Save it and then select File, Export as STL. Accept the default conditions and choose an appropriate name. The next step is 3D printing. If you don’t have a 3D printer, don’t worry, there are lots of options. Check out our 3D printing Crash Course for reasonably priced local and overseas vendors.
These are other methods that you can use to make the terrain surface geometry into a solid for 3D printing. As mentioned above, I use rectangular planes for things like mountains that have a well defined “bottom”, and box’s for general terrain that doesn’t have a well defined end. You can also use a “Shell” method to only print a thickened surface rather than a solid block, this can save lots of material (and therefore money on the printer).
How to amend the Method above. This requires an extra step of extruding your rectangular surface into a 3D box, and then intersecting and only deleting the “above ground” surfaces so that your map has a rectangular base to it. Make sure you double click the surface to show the black dotted bounding box as above, or the intersect wont work.
“Shelling” creates a thin shell of your terrain surface rather than a solid object. If you have your own 3D printer, shelling is something that the printers software can often do for you. But many vendors charge by the volume of material used, so if you are sending it away to be made, this technique is a great way to reduce the cost of the print.
How to amend the method above to create a shell.
- After you have the rectangle in position, double click the terrain surface and choose the Move tool (Shortcut: m). Then, holding Ctrl, left mouse click the surface and drag it down to create a replica. You can type in a number to select how far exactly it moves, this will be the approximate thickness of your shell.
- Double click the rectangular surface, then hold shift and select the other two terrain surfaces, panning by holding in the middle mouse button if required. Right-click and select Intersect Faces, With Model.
- Delete the outside parts of all three surfaces. Then triple-click the inside ring of the bottom surface to select it (see below).
- Press shift and select the bottom centre surface of the model. Delete it.
- Select the bottom surface and use the extrude tool as in the “Plane Method” to thicken the base if desired
And thats it! Remember to check out our 3D printing Crash Course for a list of local and overseas vendors.