maybe these approaches for originating 'terrain' or textures might be of interest...

(QGIS mapping software exporting dxf 'lines')
https://www.youtube.com/watch?v=JxCxBREEqG0

(aspire cam - converting raster to 2.5D paths etc)
https://www.youtube.com/watch?v=HUDR5X-Cbjo

This looks 'smart' -- http://topotopo.io/ [ Edit: Dont Bother is not working]