Creating solid models from single 2D sketches

Abstract

We describe a method of constructing a B-rep solid model from a single hidden-line removed sketch view of a 3D object. The main steps of our approach are as follows. The sketch is first tidied in 2D (to remove digitisation errors). Line Iabelling is used to deduce the initial topology of the object and to locate hidden faces. Constraints are then produced from the line labelling and features in the drawing (such as probable symmetry) involving the unknown face coefficients and point depths. A least squares solution is found to the linear system and any grossly incompatible equations are rejected. Vertices are recalculated as the intersections of the faces to ensure we have a reconstructible solid. Any incomplete faces are then completed as far as possible from neighbounng faces, producing a solid model from the initial sketch, if successful. The current software works for polyhedral objects with tri hedral vertices.

An optimisation-based reconstruction engine for 3D modelling by sketching

“…Its main drawback is that it becomes a direct regularity only after faces have been detected in the line drawing, and this is a complex task when hidden edges are drawn (see [46], [47], [48] and [49]). The alternative of sketching only frontal geometry (without hidden edges) and inferring hidden parts later, when 3D geometry has been given a preliminary interpretation, was explored by [10] and [16].…”

“…Only a few reconstruction algorithms are able to act as engines in this modelling by sketch approach aimed at aiding conceptual design by single-view sketches, because they must be tolerant to faults in the drawing and work incrementally [10]. Optimisation approaches have been successfully used in this context [11] [12] because models can be updated whenever the input sketch is modified and the reconstruction process is tolerant to imperfections.…”

“…Mathematical formulation of perceptual cues (also called "regularities", or "artefacts") has been studied by a small group of researchers within the reconstruction community ( [10], [14], [15] and [16]) and has led to a poorly defined objective function, thus making a global minimum very difficult to find.…”

Separation of Line Drawings Based on Split Faces for 3D Object Reconstruction

“…Many methods have been proposed for automatically reconstructing 3D objects from single line drawings [5,7,9,10,11,15,17,19,20]. Among these methods, the two in [11] and [20] can handle more complex objects than the others.…”

Comments on "What the Back of the Object Looks Like: 3D Reconstruction from Line Drawings without Hidden Lines

“…The basic problem with this paper is that it is not even an advance on the work of Grimstead [2] [3], work which I pointed out to the authors when reviewing an earlier 2 draft of this paper submitted elsewhere. Indeed, Cao et al make the same extremely limiting assumptions.…”