I need more detail of what you are trying to do. but...importing igs into BobCAD is pretty easy. What is difficult is determining what to turn into a surface that BobCAD can then generate a gcode. The import function offers two alternatives...surfaces or solids. You need to deal with surfaces in the usual way, but if you bring in the igs as a solid then you need to use the solids menu to produce surfaces that can then be read and converted to gcode, or generate the code directly with the "Generate Tool Path" function.