I’ve been following this conversation and it seems like a good time to chime in and say that we might want to update our example of skew.
I did some exaggerated testing for myself to see the effects of the compensation and its worth noting that the machines Y-Axis is the reference component of whats straight on the machine - the compensation racks the top and bottom of the parallelogram like this…
Top is +20º comp, middle is none, bottom is -20º
(Using the M1005 I0 method, +/- 0.349066 Rad as the “I” value)
I made a calculator also, mainly to see if I understood the calculations and if they gave the same results when the parallelogram was represented skewing a different way (the way it physically does on the machine). In the process I realized that I like/trust the M1005 I0 method best. I believe that when you use the M1005 XY method you may not get a 100% predictable result because its using some kind of internal constant to represent the width that you also need to measure (in other words the two diagonal measurements aren’t enough information to do the math - a third dimension needs to be known, if you don’t give it one its using some nominal value that might not match what you physically printed).
I copied this over to a google doc to share if interested (it probably needs tweaks, I have notes in it for my own reference as I worked through it - also I was printing and measuring a 100mm shape I made to be stiffer than the Bambu Support provided shape - picture at bottom for an example. I made that shape 100mm and added the extra legs because I also measure across X&Y to use as my shrinkage factor in Orca Slicer)
