"The Topo Package contains two programs that read digital elevation data and makes STL files for use in CNC applications. Topo makes simple STL's within a 1 degree x 1 degree window; BigTopo is more flexible, and can make STLs that cover larger swaths of the planet. I have no idea of the limits, but I have made maps of Hawaii, New Zealand, and Alaska with no problems. BigTopo also gives you a lot more control over the output file. It takes less than 2 minutes to make the STL file. It will also automatically download the datafiles over the 'net to complete the region you are interested in. I recommend using this package with MeshLab and Google Earth (both are free and well-supported downloads). Each of the Topo programs have detailed PDF manuals."
Not written by me but a cool program to make topographical models using the CNC.
The programs are free but if you find these programs useful please consider the donation for the author... Help keep low cost software alive....
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Topo Package 20130304 2014-12-06
The Topo Package contains two programs that read digital elevation data and makes STL files for use