As to LASER CUTTERS you need to use .svg files not .stl or .obj files. Whew!
NOTE: Joanne Fabrics stores in your area may have Glowforge laser cutters for public use; Some of those stores sell Glowforges.
I just went to Joanne's Fabrics. Their Glowforge Plus is $15.00 per hour to rent plus the cost of the material (Plywood or Acrylic in my case). The Program they use at this store (Metaire, LA) is *Inkscape*... and, they do sell Glowforge's at this location.
I have about 16 feet of Viaduct I would like to construct... I'll have to do a cost analysis.