Gharib, IslamQin, ShengfengJohn Collomosse and Ian Grimstead2014-01-312014-01-312010978-3-905673-75-3https://doi.org/10.2312/LocalChapterEvents/TPCG/TPCG10/231-239Sketching plays a very important role in conceptual design. In this early stage of the design process, designers have developed some ways to help them to explore designs. Sketching is one of these methods. In this paper, a study of sketch nature was carried and a proposed sketch-based interface for modeling was designed. The sketch nature study investigated the cognitive activities in sketching process, analyzed sketches of design students and professional designers, and collected data about sketching process and sketch-based systems requirements from designers to develop sketching scenarios and determine sketch-based systems requirements. These requirements were used to design a proposed sketch-based system for conceptual design with a multi-windows approach. The proposed system aims to provide an easy way for designers to sketch freely and for ideas to flow easily by using a multi-windows approach for sketching, 3D generation and rendering.Keywords: sketch, sketch-based system, conceptual design, design cognition.