<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>

<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>

<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>

CC BY-SA 4.0
2019-01-31T15:17:52.053Z
2019-05-05T16:57:30.867Z
2019-05-05T16:57:30.867Z
R.. GitHub STOP HELPING ICE
<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>

CC BY-SA 3.0
2018-01-15T06:46:58.683Z
Similar issue here but both settings were 1.75.  I re-saved printer and material preferences and modified my custom settings and saved them.  Now it works!
David Lotts
CC BY-SA 3.0
2017-12-21T13:42:11.397Z
Thanks, that was it, the filament diameter was correct in the machine settings (that I checked) but not in the material section of the print settings
Nir
CC BY-SA 4.0
2017-12-21T13:30:27.923Z
2019-04-20T21:36:11.590Z
2019-04-20T21:36:11.590Z
Mick
<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>

CC BY-SA 3.0
2017-12-21T13:09:09.067Z
Maybe give your custom profile parameter so we can have a guess at what could be wrong ? I don't think someone here has enough divination skills to guess the parameters on your software.
Tensibai
CC BY-SA 4.0
2019-06-30T10:45:24.833Z
This may be a bug, because my *new* install of latest Cura is creating the same problem AND I saw 2.85 one of the settings, so I changed it to 1.75 and it continued to under extrude severely.
All was well with a Repetier print.
Now reading above I need to also check both the machine settings and material section of the print settings.
SimonSolar2C
CC BY-SA 4.0
2019-06-30T12:03:11.820Z
This is not a bug, Ultimaker default filament diameter is 2.85 mm, so that is what they default to.
0scar
<ultimaker-cura>
Under extrusion with Cura 3.1
Nir
# Under extrusion with Cura 3.1

(Asked by: username_0 on 2017-12-21)

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.

My printing is a Robo3D R1+ using the "custom FDM printer" profile.

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

**Tags:** ultimaker-cura
> **Comments:**
> **username_1**: Maybe give your custom profile parameter so we can have a guess at what could be wrong ? I don't think someone here has enough divination skills to guess the parameters on your software.  
> **username_2**: This may be a bug, because my *new* install of latest Cura is creating the same problem AND I saw 2.85 one of the settings, so I changed it to 1.75 and it continued to under extrude severely. All was well with a Repetier print. Now reading above I need to also check both the machine settings and material section of the print settings.  
> **username_3**: This is not a bug, Ultimaker default filament diameter is 2.85 mm, so that is what they default to.  

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## 2 answers

### Answer by username_5 on 2017-12-21. Score: 7 | Accepted answer

Some users have reported upgrades to Cura changing the filament size to the default 2.85 mm. If you are using 1.75 mm filament (which most printers do), you will get extreme under-extrusion.

> **Comments:**
> **username_0**: Thanks, that was it, the filament diameter was correct in the machine settings (that I checked) but not in the material section of the print settings  
> **username_6**: Similar issue here but both settings were 1.75.  I re-saved printer and material preferences and modified my custom settings and saved them.  Now it works!  

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### Answer by username_4 on 2019-01-31. Score: 5

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 **and the command line**, so `-s material_diameter=1.75` on the command line did not help. Given `$foo.def.json`, it seems to construct the filename `%$foo_extruder_0.def.json`, and if that does not exist, loads `fdmextruder.def.json`, which sets `material_width` to a default of `2.85`.

I was able to solve the problem by either patching `fdmextruder.def.json`, or making a copy of it named to match my printer's settings file, with the `2.85` changed to `1.75`.

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 `CuraEngine` from the command line unless you've set the `CURA_ENGINE_SEARCH_PATH` environment variable to include the path they're in. Alternatively you can copy them to the same directory as the main printer json files.


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