@kirchner, I tried to duplicate the process I used in creating a simple sleeve block as documented in the wiki at https://wiki.valentinaproject.org/wiki/Sleeve_Block,_McCunn_System. Here is the file I was creating as I tested the tutorial McCunn-basic-sleeve-kim-a.val (7.8 KB) and the associated measurement file McCunn_sample.vit.vit (3.3 KB)
Here is the file I started on your demo site. I got as far as creating the drafting skeleton but I did not even attempt the curves for the sleevehead because they are not circular. sleeve_a.json (1.7 KB)