Computer illustration or digital illustration is the use of digital tools to produce images under the direct manipulation of the artist, usually through a pointing device such as a tablet or a mouse. wikipedia.org

A sketch is a rapidly executed freehand drawing that is not usually intended as a finished work. A sketch may serve a number of purposes: it can be used to record something that the artist sees, develop an idea for later use or as a quick way of graphically demonstrating an image, idea or principal. wikipedia.org

Drawing is a form of visual art that makes use of any number of drawing instruments to mark a two-dimensional medium. Instruments used include graphite pencils, pen and ink, inked brushes, wax color pencils, crayons, charcoal, chalk, pastels, various kinds of erasers, markers, styluses, and various metals. wikipedia.org

Video production is videography, the process of capturing moving images on electronic media (e.g., video tape, direct to disk recording, or solid state storage like a tapeless camcorder) even streaming media. The term includes methods of production and post-production. wikipedia.org