Abstract: This paper presents a novel technique to model a three dimensional freeform surface, in its global shape and small details, using a sketching interface, from a single point of view. In the past, most modeling systems that used sketches as input reconstructed the shape from the silhouette, and the user had few control on the inner parts of the result. In our system, we generate a grid of co-planar lines from a small number of strokes that the user drew, then we estimate the normal vector where it is constrained, and we form the surface by propagating this information to the whole grid. As a result, smaller strokes act locally to add detail, while longer strokes modify the whole surface. Our system gives a new approach to the modeling from sketches problem, and is intended to be a part of a more complex modeling system.