A multi-touch application for the automatic evaluation of dimensions in hand-drawn sketches

Dimensioning plays an important role in the product development process. It is usually learned through sketching exercises where students add the corresponding dimensions to different parts of an engineering drawing. Nevertheless, being able to self-learn proper dimensioning methods is challenging, as a geometric figure requires a specific number of dimensions to be correctly defined. This paper presents an educational software application for multi-touch tablet devices to support dimensioning activities. Our application uses a multi-touch interface where students can create 2D parametric drawings with dimensions using freehand sketches and receive feedback from the system about the quality of their dimensioning exercises. When a student finishes a sketch, the system reports back the correct and incorrect dimensions. Multi-touch gestures are also used for basic sketch manipulation (panning, zooming, and rotating), similar to the standard functionality found in modern smart phones and tablets. Preliminary experiences show that multi-touch interfaces provide an effective way to capture students´ attention. Students found the system very natural, and the time required to learn how to use the application is short. They enjoyed the simplicity of the interface and valued the powerful control of the geometry.