T-Splines
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T-Splines opens up many interesting avenues for academic research. The purpose of this webpage is to stimulate research on the topic by posting links to research papers on T-Splines and to recommend important open questions related to T-Splines theory. Researchers who wish to add a link from this webpage to their T-Splines related work, please contact us. (NOTE: T-Splines, Inc. owns the exclusive license to commercialize the patented T-Splines technology.)

Publications List
  • T-Splines and T-NURCCS (SIGGRAPH'03) Thomas W. Sederberg, Jianmin Zheng, Almaz Bakenov, Ahmad Nasri

    This paper introduces T-Splines and T-NURCCs (Non-Uniform Rational Catmull-Clark Surfaces with T-junctions). T-NURCCs enable true local refinement of a Catmull-Clark-type control grid: individual control points can be inserted only where they are needed to provide additional control, or to create a smoother tessellation, and such insertions do not alter the limit surface.

  • T-Spline Simplification and Local Refinement (SIGGRAPH'04) Thomas W. Sederberg, Jianmin Zheng, Tom Lyche, David Cardon, G. Thomas Finnigan, Nicholas North

    A typical NURBS surface model has a large percentage of superfluous control points that significantly interfere with the design process. This paper presents an algorithm for eliminating such superfluous control points, producing a T-Spline. The algorithm can remove substantially more control points than competing methods such as B-Spline wavelet decomposition.

  • Adaptive T-Spline Surface Fitting to Z-Map Models Jianmin Zheng, Yimin Wang, Hock Soon Seah

    Surface fitting refers to the process of contructing a smooth representation for an object surface from a fairly large number of measured 3D data points. This paper presents an automatic algorithm to construct smooth parametric surfaces using T-Splines from z-map data. The algorithm begins with a rough surface approximation and then progressively refines it in the regions where the approximation accuracy does not meet the requirement.

  • Conversion between T-Splines and Hierarchical B-Splines Yimin Wang, Jianmin Zheng, Hock Soon Seah

    This paper presents algorithms for transformation between T-Splines and hierarchical (rational) B-Splines. With the transformation, a surface expressed in terms of T-Splines can be converted into a hierarchical (rational) B-Spline representation and vice versa. The correspondence between T-Spline representation and hierarchical (rational) B-Spline representation is generally not one-to-one. The conversion algorithms can yield compact representations.

  • Improvement on the Dimensions of Spline Spaces on T-Mesh Chong-Jun Li, Ren-Hong Wang, Feng Zhang

    This paper discusses the dimensions of spline spaces on a T-mesh by using the Smoothing Cofactor-Conformality method. The result is improved essentially with another relaxed constraint depending on the order of the smoothness, the degree of the spline functions and the structure of the T-mesh.

  • Manifold T-Spline Ying He, Kexiang Wang, Hongyu Wang, Xiafeng Gu, Hong Qin

    This paper develops manifold T-Splines. In our shape modeling framework, the manifold T-splines are globally well-defined except at a finite number of extraordinary points, without the need of any tedious trimming and patching work. We present an effecient algorithm to convert triangular meshes to manifold T-Splines. Becuse of the natural, built-in hierarchy of T-Splines, we can easily reconstruct a manifold T-Spline surface of high quality with LOD control and hierarchical structure.

  • Automatic and Interactive Mesh to T-Spline Conversion Wan-Chiu Li, Nicholas Ray, Bruno Levy

    In Geometry Processing, and more specifically in surface approximation, one of the most important issues is the automatic generation of a quad-dominant control mesh from an arbitrary shape (e.g. a scanned mesh). However, in the industry, designers still use manual tools (see e.g. cyslice). The main difference between a control mesh constructed by an automatic method and the one designed by a human user is that in the second case, the control mesh follows the features of the model. More precisely, it is well known from approximation theory that aligning the edges with the principal directions of curvature improves the smoothness of the reconstructed surface, and this is what designers intuitively do. In this paper, our goal is to automatically construct a control mesh that follows the features of a model, mimicking the mesh that a designer would create manually. The control mesh generated by our method can be used by a wide variety of representations (splines, subdivision surfaces . . . ). We demonstrate our method applied to the automatic conversion from a mesh of arbitrary topology into a T-Spline surface.

  • T-Spline Merging Heather Ipsom

    Geometric models, such as for use in CAD/CAM or animation, are often constructed in a piece-wise fashion. Historically, these models have been made of NURBS surfaces. For various reasons it is problematic and often times mathematically impossible to combine several NURBS models into one continuous surface. The recent invention of a surface type called T-splines has made the combining of NURBS surfaces into a single continuous surface possible, but much of the mathematics has yet to be explored. This thesis explores the mathematics and algorithms necessary to merge multiple NURBS, T-spline, or T-NURCC surfaces into a single continuous surface. This thesis addresses two main problems. The first problem is merging surfaces with different parameterizations. In order to merge surfaces with different parameterizations, it is often necessary to modify the parameter values of the surface, which can change the shape of the surface. This change can be alleviated through shape control methods. The second problem is merging surfaces that meet at extraordinary points, or points with a valence other than four. Results show that the merging algorithm is able to successfully convert models composed of multiple NURBS, T-spline, or T-NURCCS surfaces into models composed of a single T-spline or T-NURCC surface. The resulting models are gap-free and contain little distortion in the parameterization.

  • T-Spline Simplification David Cardon

    This work focuses on generating approximations of complex T-spline surfaces with similar but less complex T-splines. Two approaches to simplifying T-splines are proposed: a bottom-up approach that iteratively refines an over-simple T-spline to approximate a complex one, and a top-down approach that evaluates existing control points for removal in producing an approximations. This thesis develops and compares the two simplification methods, determining the simplification tasks to which each is best suited. In addition, this thesis documents supporting developments made to T-spline research as simplification was developed.

  • Isogeometric Analysis using T-Splines Y. Bazilevs, V.M. Calo, J.A. Cottrell, J.A. Evans, T.J.R Hughes, S. Lipton, M.A. Scott, T.W. Sederberg

    We explore T-splines, a generalization of NURBS enabling local refinement, as a basis for isogeometric analysis. We review T-splines as a surface design methodology and then develop it for engineering analysis applications. We test T-splines on some elementary two-dimensional and three-dimensional fluid and structural analysis problems and attain good results in all cases. We summarize current limitations and future opportunities.

  • Watertight Trimmed NURBS Thomas W. Sederberg, G. Thomas Finnigan, Xin Li, Hongwei Lin, Heather Ipson

    This paper addresses the long-standing problem of the unavoidable gaps that arise when expressing the intersection of two NURBS surfaces using conventional trimmed-NURBS representation. The solution converts each trimmed NURBS into an untrimmed T-Spline, and then merges the untrimmed T-Splines into a single, watertight model. The solution enables watertight fillets of NURBS models, as well as arbitrary feature curves that do not have to follow isoparameter curves. The resulting T-Spline representation can be exported without error as a collection of NURBS surfaces.

  • T-Splines: A Technology for Marine Design with Minimal Control Points Matthew T. Sederberg, Thomas W. Sederberg

    A typical NURBS hull model involves far more control points than are needed for the design process, which needlessly complicates fairing and form finding. A relatively new surface representation called T-splines eliminates the superfluous rows and columns of control points that are unavoidable in NURBS. This paper presents methods for designing hulls using T-splines.