I am using OpenBuilds CAM to do marquetry with a laser. It works great with closed shapes, but if the lines are open, it adds a line segment to close it when cutting. Is there any way to inhibit this?
not an issue, a design feature (-: Sketchup Make 2017 (search resoruces for it) with the SketchUcam plugin (link in my signature) will do what you need
Another option is Cambam, no issue's with open polylines. Just some very minor tweaking to default post processor. All works as expected.