What to do in the following situation (still haven't figured it out a week on)? - perimeters OK - infill OK but bottom layers (on the inside!), top layers and especially gap fill are all problematic It looks to me like whenever the nozzle does a U turn there's extra plastic left behind and that rapidly builds up into little piles which are pretty horrible to find on the top layer and make the nozzle bounce on the inside. Initially I thought it was because I'd set a wide extrusion width but even on the Simplify auto setting (0.4mm +20%) just the same. It's like I can't wait for the bottom layers to be out the way and onto regular infill. Then whenever a patch of gap fill comes up my heart sinks. It wasn't nice with PLA but with XT it's horrible. What do I need to adjust?