<p>I upgraded from Cura 2.7 to 3.1.0 and I'm getting horrible under extrusion, I'm sure this is the software because I rolled back to 2.7 and everything is working fine again.</p>

<p>My printing is a Robo3D R1+ using the "custom FDM printer" profile.</p>

<p>Is there any new setting or a setting that isn't migrated properly that causes this?</p>

[{'answer_id': 5163, 'author': 'Mick', 'author_id': 3953, 'author_profile': 'https://3dprinting.stackexchange.com/users/3953', 'pm_score': 4, 'selected': True, 'text': '<p>Some users have reported upgrades to Cura changing the filament size to the default 2.85&nbsp;mm. If you are using 1.75&nbsp;mm filament (which most printers do), you will get extreme under-extrusion.</p>\n'}, {'answer_id': 8109, 'author': 'R.. GitHub STOP HELPING ICE', 'author_id': 11157, 'author_profile': 'https://3dprinting.stackexchange.com/users/11157', 'pm_score': 3, 'selected': False, 'text': "<p>I hit this issue again in January 2019 with CuraEngine 3.6+git. Since support for multiple extruders was added, it now auto-loads a per-extruder settings file that overrides the main settings file <strong>and the command line</strong>, so <code>-s material_diameter=1.75</code> on the command line did not help. Given <code>$foo.def.json</code>, it seems to construct the filename <code>%$foo_extruder_0.def.json</code>, and if that does not exist, loads <code>fdmextruder.def.json</code>, which sets <code>material_width</code> to a default of <code>2.85</code>.</p>\n\n<p>I was able to solve the problem by either patching <code>fdmextruder.def.json</code>, or making a copy of it named to match my printer's settings file, with the <code>2.85</code> changed to <code>1.75</code>.</p>\n\n<p>Update: There should already be extruder files for supported printers, but they're in a different directory, so they won't be found when invoking <code>CuraEngine</code> from the command line unless you've set the <code>CURA_ENGINE_SEARCH_PATH</code> environment variable to include the path they're in. Alternatively you can copy them to the same directory as the main printer json files.</p>\n"}]
['https://3dprinting.stackexchange.com/questions/5161', 'https://3dprinting.stackexchange.com', 'https://3dprinting.stackexchange.com/users/170/']