UPDATE 5-29-19 - Beta 5:
Started nearly from scratch on the 3a cutout, as I wasn't satisfied with the prints I was getting with the previous one, or the final one using the SCAD design. I don't know if compiling out just the shell slightly changed the sizes or what, but every print I made with the stock SCAD shell was far too large. I finally remeasured the phone, sized everything to about ~1.4mm larger than the phone shell, and got a winner. The beta 5 case fits nearly flush with the device with no play. it is essential you remove any excess material/defects from inside the shell as it will prevent the device from fitting and may crack the case. I still plan to tweak the design a bit more before moving on to cutting/gluing the folio cover on (I still don't like the power/volume button area, and the camera/fingerprint cutouts are about 0.4mm off center. I'm guessing about 1-2 more design iterations before a "final" version (both with the area where the folio cover will glue in, and a version without that area) Right now I love how the case feels in my pocket, it isn't bulky like my existing folio cover, and I'm going to do my best to retain that slim feel when I add the cover.
UPDATE 5-24-19 - Beta 3:
Getting very close! Tested beta 2, didn't have any of the brittleness of past prints, but still needs a few tweaks, the case was hugging the phone too tightly and caused the case to fracture after a squeeze gesture. also the volume opening is too thick and it's difficult to press the buttons, i'm lowering the cutout there to hopefully make that area easier to access. I've made an insert for the magnet, but I don't have the magnets yet (they're in the mail) so i'm not 100% sure it will work where I currently have it. (on the border right below the volume button, hoping it works there so it will hold the folio cover opened and closed. it's made to fit a 1mm thick 2mm diameter magnet. (bought them online 100 for like 6 bucks?) Once again, I haven't test printed this new version yet, will update this post when I have.
UPDATE 5-23-19 Beta 2:
Test print didn't go well, I'm refining the design and re-modeling the base pixel reference model as I'm unhappy with the fit. Additionally I made the walls far too thin, and the case is fairly brittle. I've uploaded a new STL and .blend file to address these changes, but once again I haven't finished a test print with these changes. In addition the new print has my folio back cutout so it requires supports to print. once I have the print finalized, I'll use that to make a SVG to cut the material for the folio case cover. Also, just as a note for those that have also been on the hunt for a ultra thin folio case, while it will have a flip cover, the cover will not be able to turn the display on and off, as the 3a lacks a hall sensor. I'm still planning to include a magnet slot in the case so you can magnet the case closed.
Work in progress! I am not happy with the final print quality yet and have not finished the design of the folio cover, if you print it early there is no guarantee your print will be compatible with my final instructions!
I'm working on a slim folio-style case for my pixel 3a. I have finished the base body of the case, I have not yet had the chance to print it so I don't know if this case will work without any tweaks. I've included my .blend file if anyone wants to tweak it a bit to their needs. I'm hoping to be able to print this in PLA or ABS, and I will add the folio cover print and cut instructions (cover will be a combo of cloth, 3D printed insert, and vinyl cut with 2D plotter.) as well as a full photo step-by-Step when I've finished it.
Thanks to jpickens for letting me extract their model of the 3a from their SCAD file!