I purchased a Creality Ender 3 Pro about a month ago and have had stunning success thanks to Thingiverse, YouTube and the entire maker community. 3D printing has quickly become a passionate hobby for me (an old CIM/CAM/electronics/IT former Marine with a grumpy attitude and a lot of ammo - LOL).
This first "Thingy" is a calibration block measuring 10mm x 20mm x 30mm with 3 centered, intersecting holes in each direction (8mm diameter).
The purpose is to see opportunities for additional calibrations that the printer might need and what side/direction is causing the flaws. The block also acts as a mechanical calibration for the gantry/bed/uprights relationships.
I'm having difficulties understanding the level of accuracy so this STL file may be version 1 while I learn to modify my Inventor/Fusion/TinkerCAD models to compensate for the natural inaccuracies of oozing melted plastic through a really tiny hole.
I'm a noob here so be gentle ... ;)