Curvature-based blending of closed planar curves

Abstract: A common way of blending between two planar curves is to linearly interpolate their signed curvature functions and to reconstruct the intermediate curve from the interpolated curvature values. But if both input curves are closed, this strategy can lead to open intermediate curves. We present a new algorithm for solving this problem, which finds the closed curve whose curvature is closest to the interpolated values. Our method relies on the definition of a suitable metric for measuring the distance between two planar curves and an appropriate discretization of the signed curvature functions.

M. Saba, T. Schneider, K. Hormann, R. Scateni.
Curvature-based blending of closed planar curves.
Graphical Models, 76(5):263-272 (GMP 2014, Singapore, SN).
Elsevier, September 2014.

A Multitouch Notice Board Fostering Social Interaction

Abstract: We report on an alternative OCGM interface for a bulletin board, where a user can pin a note or a drawing, and actually shares contents. Exploiting direct and continuous manipulations, opposite to discrete gestures, to explore containers, the proposed interface supports a more natural and immediate interaction. It manages also the presence of different simultaneous users, allowing for the creation of local multimedia contents, the connection to social networks, providing a suitable working environment for cooperative and collaborative tasks in a multi-touch setup, such as touch-tables, interactive walls or multimedia boards.

Authors: S. A. Iacolina, M. Corrias, O. Pontis, A. Soro, F. Sorrentino, R. Scateni.
A Multitouch Notice Board Fostering Social Interaction.
ACM SIGCHI Italian Chapter (CHItaly 2013), 13:1–13:4.
Trento, Italia, Settembre 2013.

PolyCut: Monotone Graph-Cuts for PolyCube Base-Complex Construction

Abstract: PolyCubes, or orthogonal polyhedra, are useful as parameterization base-complexes for various operations in computer graphics. However, computing quality PolyCube base-complexes for general shapes, providing a good trade-off between mapping distortion and singularity counts, remains a challenge. Our work improves on the state-of-the-art in PolyCube computation by adopting a graph-cut inspired approach. We observe that, given an arbitrary input mesh, the computation of a suitable PolyCube base-complex can be formulated as associating, or labeling, each input mesh triangle with one of six signed principal axis directions. Most of the criteria for a desirable PolyCube labeling can be satisfied using a multi-label graph-cut optimization with suitable local unary and pairwise terms. However, the highly constrained nature of PolyCubes, imposed by the need to align each chart with one of the principal axes, enforces additional global constraints that the labeling must satisfy. To enforce these constraints, we develop a constrained discrete optimization technique, PolyCut, which embeds a graph-cut multi-label optimization within a hill-climbing local search framework that looks for solutions that minimize the cut energy while satisfying the global constraints. We further optimize our generated PolyCube base-complexes through a combination of distortionminimizing deformation, followed by a labeling update and a final PolyCube parameterization step. Our PolyCut formulation captures the desired properties of a PolyCube base-complex, balancing parameterization distortion against singularity count, and produces demonstrably better PolyCube base-complexes then previous work.

Authors: M. Livesu, N. Vining, A. Sheffer, J. Gregson, R. Scateni.
PolyCut: Monotone Graph-Cuts for PolyCube Base-Complex Construction.
ACM Transactions on Graphics, 32(6):171:1-171:12 (Siggraph Asia2013, Hong Kong).
ACM, November 2013.

Controlling a planetarium software with a Kinect or in a multi-touch table: a comparison

Abstract: The wide availability of low-cost sensing devices is opening the possibility to easily create different interaction settings, which exploit various techniques for a more natural interaction, especially in public and shared settings. In this paper, we compared two different solutions for enhancing the interaction experience of a planetarium application, both replicable at a reasonable cost. The first version is based on a simple multitouch paradigm, while the second one exploits a full-body interaction together with a projection on geodetic sphere. We detail the technical implementation of both versions and, in addition, we discuss the results of user-study that compared the two modalities, which highlights a tradeoff between the control and the users’ involvement in the virtual environment.

Authors: E. Tuveri, S. A. Iacolina, F. Sorrentino, L. D. Spano, R. Scateni.
Controlling a planetarium software with a Kinect or in a multi-touch table: a comparison.
ACM SIGCHI Italian Chapter (CHItaly 2013), 6:1–6:4.
Trento, Italia, Settembre 2013.

A Grammar-Based Approach to the Modeling of Animal-like Characters

Abstract: We present here the preliminary results of our efforts towards the de?nition of a novel paradigm for the procedural generation of pseudo-animals, using a grammar-based approach. With the term “pseudo-animal” we denote a living being characterized by a set of features mimicking the ones of real animals, but not necessarily belonging to existing species. The generation of these pseudo-animals should also plausibly re?ect the properties of the environment where the model will live.

Authors: F. Usai, M. Kovacic, R. Scateni.
A Grammar-Based Approach to the Modeling of Animal-like Characters.
CG Libs Smart Libraries for Computer Graphics (poster).
Pisa, Italia, Giugno 2013.