Just wanted to pass along an idea I had and a method for doing this. The bottom layer of the print is typically very smooth. The top layer not so much. I'm mainly using S3D, and a feature it lacks (for me) is the ability to tell the top layer to print the infill first and the outline last. Of course, this wouldn't always make sense, as the infill often uses the outline as something to hang on to, but for many models, the top 3 layers are solid, and so that final layer could almost always swap the order of drawing in order to get a slightly nicer top finish. The other thing about the top finish is that you may well have a spot of over-extrusion just to make sure you don't have under extrusion. You're always on a knife edge there. So you're top layer is probably a touch rougher than maybe you'd like. If so, perhaps this process is for you. So, my idea is to basically go back over the top layer, movement for movement, with just a hot end, and no actual extrusion. This isn't an option in S3D (maybe it is in other extruders?). And so, it's time to open notepad++ or whatever you want to use. The first job is to isolate that final print layer. I copy that and move it to a new page so I can operate on it in isolation from the rest of the file. The first step is to cut out all extrusion commands. The operation of the printer is typically just to move and extrude at the same time. So a typical draw command look like this G0 X122.45 Y100.4 E30 To turn this from a draw to a smooth, we just need the head at the same level and turn off the extrusion. So for that I use Notepad++'s search and replace facility with a regexp to replace E[.0-9]+ And then I replace it with nothing at all. So that snips out all extrusion commands. We still have a few lines that were retraction moves so I find those and remove them be replacing G0 F.* Again replace this with blank. That should remove all the retractions. Now, I've got a set of GCODES that will repeat that final layer but not extract any more filament. For an extra test, I've also re-ordered the GCODES (nicely commented by S3D) to switch around infill and outline moves, so it should smooth the infill first, and then finally the outline. We're not quite done here. You'll also want to get that nozzle purged so, at the beginning of the file, dock, purge, and undock. That's it. Well, I just wanted to share the idea and the process. I'm currently just printing out another twirl with this method inside to go over the final layer and smooth it off. I'd certainly be interested to hear if anyone else has tried to do this or has some fancy, easier way, to get to a similar end result. Ideally S3D should handle this for all exposed top layers. My method above is only going to work for the final top layer, not all top layers in a more complex part.