I like to work with g-code but I can do stl files also. I use a software called bmp2cnc to create g-code. I work quickly because I use raster software to make the patterns. This gives me more standard tools to use that aren’t available in 3D software. Since I work fast it doesn’t cost that much. I also use zbrush software to make stl files. So it’s an extra step in the process. The cost is more for that extra step. I would have to smooth things out, define details and compress the mesh down to a size that is able to be emailed. So the cost for this would be $1.20 for each sculpted object rather than $1.00 standard charge for contoured objects. So it’s not much more especially for simple patterns.