In my quest to tune my various settings I decided I needed to be able to automatically generate a test file that would change the pressure advance at set intervals.
The only programming language I know is Delphi/Lazarus, so I created a windows application to carry out the task.
Essentially that application creates a square box with two wall perimeters.
The inner wall prints at a constant speed and acts merely for support.
The outer wall alternates between a high and low speed with the transition point being mid way along the wall.
At the end of each layer a retraction is added.
This allows you to see how the PA adjustments are affecting corners at the two speeds and how it is affecting the retraction settings.
A start and end G code section takes care of temps etc.
Here are some pics of tests starting a PA of zero and increasing by 0.05 every 5mm in height.
My printer runs about a 350mm bowden tube.
Pic 1: PA range 0-0.35
Note the distinct thickness variations at the speed change point and the blobbing at the retraction/layer change point.
Pic2: PA Range 0.4-0.75
Transition line still faintly visible and some issues around retraction area
Pic3: PA range 0.8-1.15
Looks pretty good at about mid way
Pic4: PA range 1.2-1.55
Here we can see that pressure advance is starting to cause too much retraction.
I'd either have to reduce PA or try again with less retraction.
If anyone would like to try the application and provide feedback , I have put a link to my dropbox.
This should be considered very much beta software.
Use at your own risk.
I've only tested on Windows 10.
I'm not sure my extrusion volume calculations are 100% accurate.
They seem close, but not identical to Cura's values.
At any rate it seems good enough for the test purposes.