Visual Design Methods in Interactive Applications Jean Vanderdonckt Keywords Graphical Applications, Grid, Interaction Objects, Interactive Objects, Layout, Multimedia Applications, Visual Interface Design and Management, Visual Interaction, Visual Placement, Visual Techniques. Introduction Visual design in general is interested in arranging information items (e.g., text, images, diagrams, pictures, tables) in such a way that it is visually attractive, perceptive and easily understandable. Visual design issues are raised in many domains of human activity such as user interface design, documentation development, presentation design, and graphic layout. This chapter heavily relies on techniques coming from visual design as used in typography to expand them to user interface design. When the designer sketches the components of a user interface, the first thing to do is to select appropriate interaction and interactive objects according to the user's task. The second activity is to determine the basic layout of these selected objects ranging from the most important to the least important: the main application window, the title and menu bars, the functional areas of the application window (e.g., a status bar, a toolbar), all child windows, dialog boxes and panels with their contents. This layout consists of interaction objects and interactive objects. Interaction objects (IO), also called widgets or controls, encompass static objects (e.g. labels, separators, group boxes) and dynamic objects (e.g. edit boxes, radio boxes, option boxes). Interactive objects cover every other kind of object that a multimedia user-interface could virtually display : static icons, drawings, pictures, images, sketches, video sequences, graphics,… Each of these objects allows some special interaction with the user. For instance, an image of the human body may include hot spots for defining different sensitive regions of the body in order to be selected, displayed, explained or zoomed. Some images can be extracted from a video sequence in order to be analysed. Interaction and interactive objects will be further referred to as IO. Figure 1. (a) A layout of a dialog box ; (b) The underlying layout grid Determining the basic layout consists of calculating and drawing any geographical composition of functional areas of the user interface into a comprehensive format depending on the user's task. In particular, solving the layout problem for a dialog box consists of drawing aside the set of related IO, assembling them into a rectangular area, and surrounding them by borders. The layout then looks like a set of rectangles when drawn around each IO (fig. 1a). A layout grid consists of a set of parallel horizontal and vertical lines that divide the layout into units that have visual and conceptuel integrity (de Baar, Foley, & Mullet, 1994 ; Feiner, 1991 ; Marcus, 1992 ; Taylor ; 1960). The intersections of these lines delimit these units into rectangles that constraint the IO position (fig. 1b). Equally spaced lines typically establish external margins in the layout and