Secrets, part two: Invention
2.) Invention: Once a draftsman has mastered the ability to reproduce the object before him, he begins to “delineate upon some surface, a subject from memory or from a book…or from imagination (fantasia), which is commonly called inventar or to debujar con fantasia” in order to “bring to light ideas from understanding which were conceived by means of reason, discourse, observations and precepts.”
The key to invention is knowledge, practical and theoretical.