Try to figure out MBL values

[cabbagecreek]

I have tried to do Software that improves the manual MBL process.
I had a discussion with Scott Lahteine and he sad that Roxanne may have a clue (Roxy at this board??? )
This is why I try to post my question here.

My intension is to NOT change anything inside Marlin.
I want to begin with the Marlin standard configured and with MBL setup working.

Then I use the G29 to get the report of the FW configured and Manually done MBL. In my case the mesh is 3 x 3 points.
G29 and parse the responce to get number of x & Y ponts and the manually meassured values for each point
The point X1/Y1 has the Z value 6.975. (To keep the description short I concentrate to one single point)

Then I do the G29 S1 = Start probing mesh points.
The nozzle moves to the meshpoint..
M114 gives me the position of the first position ( X35 Y35 = X1 Y1)
Z is irrelevant now.
G29 S2 is Move to next MeshPoint. Redo the same procedure for all 3x3 points.


After this I got 9 points with X/Y where the nozzlepositions for MBL.


I recalculate the X/Ypositions so the PROBE will be at the exact position as the nozzle using ProbeOffsets X/Y

I do G30 on each of the MBL points and gets values. On the X1/Y1 point I get the value 3.01


Now the question is how I get the manual MBL value 6.975 from the probed value 3.01.
The most obvious solution is 10 - probed value = mbl value 10 - 3.01 = 6.99 ( close to manually value of 6.975)

But where do I get the 10 from.. Is this a fixed/hardcoded value inside Marlin or is it possible to configure in configuration.h

When I have the mbl points probe-values recalculated (3.01 become 6.99) I will do
G29 S3 X1 Y1 Z6.99 to adjust the MBL points with the probe-value.



I am sooo close to have a semiautomatic MBL done in software outside Marlin.
I hope that I can get some feedback if this approach is possible and will work for many kind of implementations of Marlin