Hi Pilou, there is an "Iso cut" function built in to the Edit > Trim command. It will be shown at the "Select cutting objects" stage of the Trim command if you have selected an individual surface as the object being trimmed:
Yes and always cool that we can make animation with the Blend function! ;) (or modify on the fly even more times after! (on the same session)
(button "planar Sections is jut shown - not used following)
