I’ve tried the VFA test that is built-in Orca Slicer, made some DIY ones, downloaded one, made one that expresses specifically 45 degree and 90 degree movements, and my newest one is a rectangle that guarantees the test will include movements both counterclockwise and clockwise. I’ve also used one of my single-walled models for a plant pot since it means I’m not wasting material one every test.
Some of these I ran on 3 separate machines and had my friend run on his machine, so 4 machines all ran one of my models to test and all produced somewhat different results. I ran my original model that had an unacceptable VFA-afflicted side on it as a spiral to check and was the sane. Unfortunately, the slicer recognizes height range modifiers are distinct objects, they are incompatible with spiralized so I switched it in favor of non-spiralized since at a given speed the results were the same.
Bi-directional VFA test:
I watched the video, and there’s definitely some meat here if it turns out to be the change in steppers from the Kickstarter Bambu X1C to the later models that is the culprit. Worth noting in the video that the prints of the parts he’s using to install the thrust bearing actually demonstrate the exact VFA I am fighting!
Check this out:
On both those faces you can see vertical lines all spaced exactly the same distance apart. That’s the 2mm VFA which seems to result from the 2mm spacing on the GT2 Belt.