How Cura Handles Profiles

[mhotze 7]

...or to better understand the way to get a grip on your settings.

For me also to gain some more understanding (please give feedback with more info!) and suggest improvements. I seem to have lost some carefully tuned settings and I could not get my head around the way Cura handles settings. So here's an attempt to get things clarified. At least, up until the moment some ambiguity in how settings are used is solved and things are self-explanatory. One of the ambiguous things currently is for instance that temperature profiles can be stored both in Material settings and User Profiles. Some of these in return influence other parameters which makes it quite tricky to setup your print and making you wonder what happens with your settings you thought you defined earlier.

So here we go. I'm on OsX (mac), and talking Cura 2.4 now with a UM3. I guess the OS does not matter that much, but the way Cura handles profiles and settings can be more subject to change depending on the version you're using.

How to figure out how settings are used in Cura

One way to approach understanding the way Cura works with settings, is to have a look what is going on "under the hood". Well, yes, not that I wanted to, but that's where I ended up. To be honost, euh, also had a peek at the competitor to check how they are doing, and if that's worth the investment instead of putting time and effort in Cura. But anyways, back to settings in Cura. It looks like there are default settings, which are stored in setting files, and user settings that overwrite the default ones. All are human-readable ascii files which make it possible to see at least what is stored. With changing Cura versions and the way settings are handled, this kind of exercise can be useful to master in that sense, in order to figure out yourself how things work with future releases.

So how are settings used?

There are multiple setting files that influence the final settings that are used:

 

• The Default Settings: Cura has default settings, which depend on the printer used. I think the default settings are stored in the application directory: Applications/Cura.app/Contents/Resources/resources/definitions. In my case, the settings are stored in the file ultimaker3.def.json.
  
• Superimposed on this, are the standard or user defined material settings. The important settings stored are Default Printing Temperature, Build Plate Temperature, Retraction speed and Distance, Standby Temperature and Fan Speed. Now the tricky thing I've seen by now are twofold. 1) Some of these parameters influence settings like printing speeds from the default settings, at least if they are not stored explicitly in a user profile. 2) Some of the material settings can also be stored in user defined profiles. It seems to be undefined behaviour which settings are actually used in those cases to calculate settings like for instance the printing speeds. I'm not sure of if this is intended or not. Getting this ambiguity solved would be beneficial.
  
• There are also Standard or User Profiles. Since we're talking about finetuning settings, I'm skipping directly to User Defined Profiles. For OsX, they are located in your_home_folder/Library/Application Support/cura/quality. In case of a dual extrusion printer, the settings are stored in 3 different files. These are the settings which are extruder independent (the Global settings if you have a look at the Profile Manager in Cura), and for each extruder individually. The way it currently seems to work, is as if there are changes to either settings defined by the default printer settings or material settings, these are regarded as "updated", and can then be stored in the current user profile by clicking "update profile with current settings/overrides". Only these "overridden" settings are then stored in a user profile.
  

 

At least, I think that's the way it's working. Let me know if there's things incorrect or missing so I can update the story above if needed. Also, for non- OsX users, it could be beneficial to inform which directories are used, for other users to have a peak to their actual settings files.

The way I'm currently working is examining how my settings are stored and take some notes in a text file, and double check if the relevant parameters turn up in Cura, especially when changing filement and reverting back to settings used earlier. Note, that I've not yet found a way to delete settings in a profile (for instance to delete retraction amount in a custom profile, in order to only define them in the material profile), other than delete settings using a text editor. This helps both in de-cluttering settings and knowing what you're doing (which I hope would be solved in a future release, next of course in solving the ambiguity issue explained above). One solution could be to visualize what are default settings and what are overrides by user profiles, and what are overrides by material settings (or even ditch material settings completely and go for user profiles only).