Download pdf - How to make a 3D model using Google Earth data · How to make a 3D model using Google Earth data Written By: Ryan Lutz ... INTRODUCTION EDIT 7/25/17: Sadly, Sketchup has changed the

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How to make a 3D model using Google Earthdata

Written By: Ryan Lutz

How to make a 3D model using Google Earth data

© 2017 matterhackers.dozuki.com Page 1 of 20

INTRODUCTION

EDIT 7/25/17: Sadly, Sketchup has changed the map service they use to grab location data, so theaerial satellite imagery and 3D topography are no longer available, even in previous versions ofSketchup before 2017. As such, this guide no longer works.

This guide outlines the process for creating a 3D topographic model using free software.

You will also need the SketchUp STL extension, available for free through the Sketchup ExtensionWarehouse: https://extensions.sketchup.com/en/conte...

TOOLS:Sketchup (1)

Blender (1)



https://extensions.sketchup.com/en/content/sketchup-stl

https://www.sketchup.com/download

https://www.blender.org/

Step 1 — Grab the terrain data

Open Sketchup.

Navigate to the File menu > Geo-location > Add Location...

Step 2

Navigate to the area you want tomake a model of.

In this case, I've chosen the highestpoint in the contiguous UnitedStates, Mt. Whitney (which I climbedin 2012).



Step 3

Once you get the borders exactlywhere you want them, click SelectRegion at the top right

Take a screenshot of the resultingscreen. We will reference thesatellite imagery in a future step toflatten out certain parts (i.e. thelakes).

If you need a good (free)screenshot utility for Windows, tryGreenshot.

Once you have the screenshot, clickGrab to import the Google Earthmesh data into Sketchup.

Step 4

After a few seconds, a flat image of the area you just grabbed will show in the main Sketchupscreen.

Navigate to the File menu > Geo-location > Show Terrain.



http://getgreenshot.org/

Step 5

With the Sketchup STL extension installed, you can navigate to the File menu > Export to STL andsave the file.

In case you need the extension, you can find it here: Sketchup STL Extension

For Export unit choose Feet. You can realistically choose any unit you want, but choosing Feetwill make the model more manageable in Blender, and you can always scale it again later.



https://extensions.sketchup.com/en/content/sketchup-stl

Step 6 — Import into Blender

Open Blender and delete the cube from the startup scene.

Blender has a feature called 'Clipping' that only shows the model at a certain distance, so in caseyour model is too big to show all of it, increase Clip in the properties area of 3D View to some largenumber (I use a series of six nines).



Step 7

Navigate to the File menu > Import > Stl (.stl) and choose the file you exported from Sketchup.

Once the model loads, press the S key (hotkey for scale) then enter .01 to scale it to 1/100th of itssize. Hit Enter to save the scale.

Your mouse cursor must be in the 3D View pane to use any hotkeys associated with the model,so if you don't see a change after pressing the key, check where your mouse is.

You might need to zoom out (mouse wheel) to see the whole model.

To remove the grid, navigate to the Properties section of 3D View, expand the Display section, anduncheck Grid Floor.



Step 8 — Remove triangulation

We're going to edit the mesh manually, so we need to make the geometry easier to work with.

With the mesh selected (it will have an orange border around it), press the Tab key to enter Editmode.

The mesh will highlight every edge and vertex in orange, indicating that they are all selected.

With everything still selected, press Alt+J to turn the mesh into quads instead of triangles.

Some of the squares along the sides might not change; that's okay. Areas that you need to edit willtypically be turned into quads.



Step 9 — Add reference image

Deselect everything by pressing the A key.

In Properties, scroll down to the Background Images section, check the box, and click AddImage.

Scroll down further to view the recently-shown options for Background Image and click Open.

Choose the screenshot you took in step 3.

Step 10

Navigate to the View menu at the bottom left of 3D View and switch to Orthographic view byclicking the View Persp/Ortho menu item (or simply press the Numpad 5 hotkey for this function).

From the View menu, choose Top (or press the Numpad 7 hotkey).

You will now see the model from above, looking down.



https://en.wikipedia.org/wiki/Orthographic_projection

Step 11 — Rotate model (if needed)

Sometimes the exported model isn't perfectly aligned. If your model comes out rotated a little, youwill need to correct this.

Press the Tab key to exit Edit mode.

Press the R key and use your mouse to rotate the model so it is straight.

You can fine tune the rotation angle using the modifier field on the left.



Step 12

Scroll down Properties to reveal the Background Images options, if necessary.

Click Front to bring the background image in front of the model.

Use the X and Y fields to position the model, and Rotation and Size to match the border to itsedges. You might need to adjust the Opacity to get a good view.



Step 13 — Flatten areas (optional)

Some of the lakes in the model didn't quite come out flat, so we're going to manually flatten them.

Zoom in to the area you want to flatten.

Press Tab to enter Edit mode again.

If the grid around the area you want to flatten isn't very high definition, you can subdivide the gridinto smaller squares.

Change to Face select mode by clicking the icon at the bottom of the screen of the cube withone side highlighted.

Press the C key to use the Circle select tool, and use your mouse cursor to make the selectionarea bigger or smaller.

Select all the faces over the area you want to have more definition, then press Escape to exitCircle select mode.

Press the W key and choose Subdivide. You can do this more than once to get more definition,but be careful as too much detail can add unnecessary complexity to the model.



Step 14

Press A to deselect everything, then

Switch to Vertex select by clickingthe icon of a cube with a dot at thetop left near the bottom of thescreen.

Step 15

Use Circle select again (hotkey: C),this time to select all the verticesinside the boundaries of the lake.

Remember that you can alwaysmake the mesh more detailed bysubdividing the geometry.



Step 16

Press Escape to exit Circle select.

Change Pivot center forrotation/scaling to Active Element.

This will help us in the next stepby using the location of a selectedvertex as the height to which therest of the selected points will beadjusted.



Step 17

Use your middle mouse button to rotate the view so that you can see the height of the selectedmesh.

Choose a vertex is at the height you want the mesh to be flattened to, then, holding the Shift buttonon the keyboard, use your right mouse button to de-select then re-select it.

This will change the Active Element to the vertex, which is now highlighted in white with theAxes centered on it.

Press S (for scale), then Z (to constrain the movement to the Z axis), then 0 (for the height relativeto the Active Element), then Enter (to finish the scale).

This will scale the height of all selected vertices to that of the one which was selected.

Step 18 — Smooth

From here, use the Smooth tool in Sculpt mode to smooth out any inconsistencies between the flatarea and the rest of the model.



Step 19

Repeat steps 13-18 for any other flat areas.

Step 20 — Add a base

Next, we'll make the model into awatertight object so we can export itfor 3D printing.

Zoom out (mouse wheel) anddeselect everything (hotkey: A).



Step 21

Switch to Edge select mode by clicking the icon of a cube with a line next to it near the bottom ofthe screen.

Holding the Shift and Alt keys, right-click near each of the four sides of the square to selectthem.

Step 22

Rotate the model (click and drag middle mouse button) so you can see under the model, roughlywhere you'll want the base to go.

Press Shift+D (to duplicate the selection), then Z (to constrain movement to the Z axis), thenmove the selection roughly to the height you'll want the base to be at.

Press Enter or left mouse click when you're satisfied.



Step 23

Switch back to Vertex select (cube with dot icon).

Hold Shift then right-click to de-select and re-select a vertex you want to set all the selectedpoints to, like you did to flatten the lakes.

Press S, then Z, then 0, then Enter.

Press F to create a face that will be the bottom of the model.



Step 24

Switch back to Edge select (cube with line icon).

Select the four edges of the square again (hold Shift and Alt) in addition to the bottom you justcreated.

Navigate to the Mesh menu > Edges > Bridge Edge Loops.

An "edge loop" is a loop of edges around a model, all connected in some way. In this case, we'reconnecting the loop consisting of the outside of the terrain with the loop that makes up theoutside of the bottom, essentially "bridging" the gap between the edge loops.

Step 25 — Export

When you're happy with your model, switch back to Object mode.

Make sure that the model is selected. It will have an orange border-- if not, right click on it.

Export by navigating to the File menu > Export.

Choose a name and hit Export STL.



You should now have a 3D-printable model! Import into MatterControl or any other slicer to print.

This document was last generated on 2017-08-02 03:21:34 PM.

