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If you use OctoPrint Link to manage, your 3D printer(s) then you’ve probably hit a point where you are scrolling through your list of badly named gcodes hunting for something particular, but you can’t for the life of you remember what you called it. Excellent news, you can add thumbnails to OctoPrint to make this a lot easier with a few tweaks to PrusaSlicer. If you’re a fan of SuperSlicer Link, a variant of PrusaSlicer that contains lots of more advanced features, this technique will also work with it too.
Where did thumbnails come from?
When Prusa designed the Mini (find out more information about the Prusa Mini here), they added a 32-bit main board and a colour LCD screen. This allowed them to add a brand new feature, which is to preview a print on the LCD screen. To do this, they had to add some functionality to their slicer to create that preview as a thumbnail image, and embed the image in the gcode.
As Prusa created this feature, it should not be too surprising that you must install PrusaSlicer (or SuperSlicer). If you are not used to this slicer, then it is worth learning it as it comes with some pleasant features. And compared to Cura, it is a lot faster at doing the actual slicing.
Adding Thumbnails to OctoPrint
This can all be done with some very easy tweaks to PrusaSlicer. You can set up any printer to create a preview thumbnail and then add a plugin called PrusaSlicer Thumbnails Link to OctoPrint. After this, it will show each gcode file within OctoPrint with a great looking preview.
You want that? Of course you do. So let’s get started.
Step 1: Create a Printer Profile
First off, you will need to create a custom printer profile from one of the existing default profiles. PrusaSlicer calls them custom presets. You need to do this, because you will edit this profile to add a thumbnails setting, and you cannot edit the default profiles.
On the right side of the screen, make sure you have the printer selected that you want to use, and then click the cog next to it. For example, I will do this for my Prusa i3 MK3S, so I will select that and press the cog.
Creating a custom profile is now as simple as clicking the old-fashioned floppy disk icon to save this profile. As you have a default profile selected and you cannot change those, it will ask you what you want to call this new one. Call it whatever you want.
Step 2: Have PrusaSlicer create thumbnails
Next you need to tell PrusaSlicer to generate the thumbnails. Sadly, at the time of writing this, Prusa has not added this option to the UI within PrusaSlicer. So it has to be modified by editing the file directly. It’s easy though, as it’s a text file.
Within PrusaSlicer, go to the Help menu and choose Show Configuration Folder. This will open the location on your computer with all the configuration files. Next open the printer folder. Hopefully, you will see a file with the name of the printer profile you created earlier. To add your thumbnails in OctoPrint, you need to edit this file with your favourite text editor. Make sure it’s a proper text editor, though.
Next search for a line that begins with thumbnails. It is usually at the bottom of the file and should look like this:
Edit that line so it looks like this, which specifies the size of the thumbnails in OctoPrint:
thumbnails = 16x16,220x124
Save the file. You also need to restart PrusaSlicer, so it can load in the new settings.
Step 2 is complete, now the final step.
Step 3: Display Thumbnails in OctoPrint
Go to OctoPrint as you normally would via the browser. And at the top of the screen press the settings spanner. Then navigate to Plugin Manager, scroll to the bottom and press Get More…
Add a plugin called PrusaSlicer Thumbnails Link. Let it install the plugin and restart OctoPrint. Now you have Thumbnails in OctoPrint!
From here on out, anything you slice from this point onwards will automatically show a thumbnail in OctoPrint. Much easier and much better looking.