TRIM

By hand. You can angle a member to fit corners.

Just use a column sized to width and depth , 5/4 x 4 or 6. Name it for future use.

Break the wall holding the ‘fake’ angle  , either one mentioned above , and the rest of the walls surrounding can have standard trim.

(The best method would be to just add an item to doors.  Done by Cadsoft)

Jack