A great find from Tweakie at the Openbuilds forum:
"Mach1 Filter is a little known and often overlooked, free, stand-alone, Windows based application which can be used to create the necessary GCode tool-path for producing Lithophanes, 3D Relief’s and also laser, raster scan images etc.
It was written a few years ago and is pretty basic (without all the bells and whistles often found in more up-to-date software) but it still does a good job, and can accept HPGL, JPG & BMP format images.
As with most software, to obtain the best results, a little practice is required to judge the correct brightness / contrast / sharpness for the original image but it is quickly mastered and for those wishing to try, it can be downloaded from here : http://hobbymaro.puhasoft.hu/Tweakie/Mach1Filter.exe
