Posca are spécial pencil: They use Acrylic to load the head.

Often reloading the head by pushing the pencil on the wall : Already done

The new problem :

When the LadyDraw is drawing, she process stroke one by one. But on the glass pane i use, if the LadyDraw goes more than one time on the same position, if the acrylic is dry, it will take it of and delete the previous stroke !

The solution : The software must sort the stroke todo  list by group of position , not for the fastest drawing but for the “take-care-of-acylic-specs”

Done !