1
general::
Also, rough in. Prepare or indicate in unfinished form, as in He roughed out several plans for a merger, or They roughed in where the doors would go without checking with the architect. [Second half of 1700s]
American Heritage Idioms
2
general::
Phrase(s): rough something out
to make a rough sketch of something. • I will rough it out and have one of the staff artists attend to the details. • Jane roughed out a picture of the proposed building.
McGrawhill's American Idioms And Phrasal Verbs