8093870
Reconstruction of curved solids from engineering drawings
This paper presents a new approach for reconstructing solids with planar, quadric and toroidal surfaces from three-view engineering drawings. By applying geometric theory to 3-D reconstruction, our method is able to remove restrictions placed on the axes of curved surfaces by existing methods. The main feature of our algorithm is that it combines the geometric properties of conics with affine properties to recover a wider range of 3-D edges. First, the algorithm determines the type of each 3-D candidate conic edge based on its projections in three orthographic views, and then generates that candidate edge using the conjugate diameter method. This step produces a wire-frame model that contains all candidate vertices and candidate edges. Next, a maximum turning angle method is developed to find all the candidate faces in the wire-frame model. Finally, a general and efficient searching technique is proposed for finding valid solids from the candidate faces; the technique greatly reduces the searching space and the backtracking incidents. Several examples are given to demonstrate the efficiency and capability of the proposed algorithm.
16456196
Degree reduction of B-spline curves
This work deals with the problem of degree reducing a B-spline curve without intermediate conversion to Bezier form. Degree elevation for B-spline curves may easily be described in blossom form. We also use blossoms for the degree reduction problem, and set up least squares problems for finding the B-spline coefficients directly. We also give an application to curve fairing.
13139757
Approximate merging of a pair of Bézier curves
This paper deals with the merging problem, i.e. to approximate two adjacent Bezier curves by a single Bezier curve. A novel approach for approximate merging is introduced in the paper by using the constrained optimization method. The basic idea of this method is to find conditions for the precise merging of Bezier curves first, and then compute the constrained optimization solution by moving the control points. “Discrete” coefficient norm in L2 sense and “squared difference integral” norm are used in our method. Continuity at the endpoints of curves are considered in the merging process, and approximate merging with points constraints are also discussed. Further, it is shown that the degree elevation of original Bezier curves will reduce the merging error.
16610043
Generalized Subdivision of Bézier Surfaces
In this paper, subdivision methods for rectangular Bezier surfaces are generalized to subdivide a rectangular Bezier surface patch of degreen×minto two rectangular Bezier surface patches of degreen× (m+n), while the parameter domain of the Bezier surface is decomposed into two trapezoids. As an application, a conversion from rectangular Bezier surfaces to triangular Bezier surfaces is presented.
9344765
An Efficient Algorithm for RLC Buffer Insertion
Traditional buffer insertion algorithms neglect the impact of inductance effect, which often introduces large error in circuit optimization. On the other hand, ultra-fast buffering techniques are always desirable as buffering is such a widely used technique in industry. It is a challenge to design an RLC buffering algorithm which excels in both runtime and solution quality. In this paper, such an algorithm is proposed. The new algorithm works under the dynamic programming framework and runs in provably linear time for multiple buffer types due to two novel techniques: restrictive cost bucketing and efficient delay update. Experiment results on industrial netlists demonstrate that the new algorithm consistently outperforms van Ginneken/Lillis algorithm (van Ginneken, 1990) and (Lillis, 1996) for RC buffering and all known RLC buffering algorithms. Without buffer cost minimization, the new algorithm saves up to 8.5% buffer area and provides up to 4times speedup over Ismail's algorithm (Ismail, 2001), When buffer cost minimization is handled, the new algorithm uses 33.4% fewer buffers than van Ginnenken-Lillis's algorithm, and saves up to 5.3% buffer area and gives up to 5times speedup compared to the algorithm in (Jiang et al., 2006)
5131804
Scalable peer-to-peer networked virtual environment
We propose a fully-distributed peer-to-peer architecture to solve the scalability problem of Networked Virtual Environment in a simple and efficient manner. Our method exploits locality of user interest inherent to such systems and is based on the mathematical construct Voronoi diagram. Scalable, responsive, fault-tolerant NVE can thus be constructed and deployed in an affordable way.
9549886
A case for 3D streaming on peer-to-peer networks
One of the most serious issues holding back the widespread of 3D contents on Internet has been their inaccessibility due to large data volume. Many compression and progressive transmission techniques, as well as format standards, have been proposed in recent years to make 3D streaming increasingly viable for the efficient and accessible delivery of 3D contents. However, existing proposals have yet to seriously address one of the most important issues in practical adoption - a system's scalability in terms of the number of concurrent users. We argue that due to 3D contents' large data volume and interactive nature, client-server architecture, with its inherently fixed resource availability and high cost, will not be suitable to support popular Internet-scale 3D streaming. On the other hand, peer-to-peer (P2P) architectures hold the promise of both scalability and affordability. In this position paper, we describe the potential promises and challenges in adapting 3D streaming to P2P networks, using multi-user networked virtual environment (NVE) as an example. We also propose Flowing LoD (FLoD), a scalable, distributed and fault-tolerant P2P 3D streaming mechanism, that is based on Voronoi-based Overlay Network (VON), a P2P overlay specifically designed for NVE applications.