Hi Ray, it sounds like you've got the slicing covered, but just to make sure yes like Pilou write above you can use boolean difference to slice a solid with a 2D curve including a set of lines and the booleans are oriented around keeping things solid so the lines will leave the "side walls" where they cut, resulting in solid sliced results unlike Trim.
Thank you for your helpful help that you gave me. Without you I can't menage. I know AutoCAD but MOI 3D is something for me when I discover it. It's so powerful that you have Moment of Inspiration for me is a good title.