As you already know I’m always interested in ways to print maps, and depending on the use and on the cartographic data you have the steps might be different.
This time I already had all the needed geographical data, what I didin’t have was time to process it, so I used some shortcuts
First of all I used Qgis to open a map of the city and trace the outlines of the buildings I was interested in as a new shapefile layer.
Then I got the DEM of the area and used “Stretch to Min Max” to enhance the contrast. I changed the color of the buildings to a shade of grey and then decided for 2 different shades because I had a big altitude difference between one group of buildings and the other and using the same color created skyscrapers on the sea level! All this could also be done with an image editing software if you have a grey scale image and know where the building have to go.
I then fed the screen shot to OmNomNom, inverted the colors (after realizing I had very deep swimming pools instead of high buildings!) and exported it as a Surface Map
The software opens up OpenScad that shows the future output.
It’s time for some rendering (F6, Compile and Render) and then STL export.
The output has some flaws… a wall on one side that can be easily eliminated in Cura using “Cut off object bottom” if printed in vertical position, but also…
an awful empty layer! And this was a big problem… Jonathan corrected in Openscad (no details, sorry I have no idea HOW he did it) but I’ll have to check for future prints. Loo’s like it’s between the data and the bottom layers he adds to it.
The final result looks like this: ICTP’s Campus in 3D.
There are some things to improve: printing in vertical position gives better results (even though horizontal position gives you some very nice looking level lines) and the problem with the gap needs to be solved in a better way. But adding the buildings this way was easier and more accurate than doing it with sketchup would have been. In sketchup files like these have problems opening up and anyhow you then have to guess where the buildings to add are.
Now the next step is to solve the gap problem. And doing the buildings with a different color using dual extrusion would be cool!