Ajay Joneja

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We describe two new shape operators that superimpose wrinkles on top of a smooth NURBS surface. Previous research studying wrinkles focused mostly on cloth modeling or in animations, which are driven more by visual realism, but allow large elastic deformations. Our operators generate wrinkle-shaped deformations in a region of a smooth surface along a given(More)
3-D CAD models are an important digital resource in the manufacturing industry. 3-D CAD model retrieval has become a key technology in product lifecycle management enabling the reuse of existing design data. In this paper, we propose a new method to retrieve 3-D CAD models based on 2-D pen-based sketch inputs. Sketching is a common and convenient method for(More)
In this paper, a new dynamic developable surface model is proposed. The proposed model represents developable surfaces using triangle meshes. A novel algorithm is proposed to introduce the Hamilton principle into these meshes such that the resulting developable model is dynamic, i.e., it can offer a time-dependent continuous path to deform the model.(More)
In this paper, we present a feature-based free-form shape modelling technique based on solving a fundamental problem of reconstructing the depth information from 2D sketch planes. First, to mathematically define the problem with the human perception, the proposed technique (1) formulates the 2D shaded regions on sketches by a hybrid thin plate surface model(More)
In this paper, we present a BPM (Bézier Patch Mapping) algorithm which generates a strictly non-self-overlapping structured quadrilateral grid in a given four-sided planar region. Given four pieces of polynomial curves which enclose a simple region in the plane, the algorithm first constructs a Bézier patch which interpolates the four curves (as its four(More)
Polygon partitioning is an important problem in computational geometry with a long history. In this paper we consider the problem of partitioning a polygon with holes into a minimum number of uniformly monotone components allowing arbitrary Steiner points. We call this the MUMC problem. We show that, given a polygon with n vertices and h holes and a scan(More)
A simple and linear-time algorithm is presented for solving the problem of traversing a machining graph with minimum retractions encountered in zigzag pocket machining and other applications. This algorithm finds a traversal of the machining graph of a general pocket P with N h holes, such that the number of retractions in the traversal is no greater than(More)
The modeling and analysis of a butting assembly in the presence of workpiece surface roughness and part dimensional error Abstract Butt joints are frequently used in assembly processes. However, relatively little attention has been paid to the proper design and selection of butt joint geometries and processes. In this paper, the assembly accuracy(More)
Authorization I hereby declare that I am the sole author of the thesis. I authorize the Hong Kong University of Science and Technology to lend this thesis to other institutions or individuals for the purpose of scholarly research. I further authorize the Hong Kong University of Science and Technology to reproduce the thesis by photocopying or by other(More)