INTERIOR DESIGN ILLUSTRATED The skill to express a vision with a hand-rendered drawing gives an interior designer a distinct advantage in communicating with clients. Interior Design Illustrated: Marker and Watercolor Techniques helps students develop this powerful marketing tool. The step-by-step approach, with simple, uncomplicated lessons that progress from beginner to intermediate skill levels, teaches students how to visualize interior space and perspective and details such as pattern and texture and to render their vision with watercolor and markers.