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56
Hierarchical mesh segmentation based on fitting primitives
 THE VISUAL COMPUTER
, 2006
"... In this paper we describe a hierarchical face clustering algorithm for triangle meshes based on fitting primitives belonging to an arbitrary set. The method proposed is completely automatic, and generates a binary tree of clusters, each of which fitted by one of the primitives employed. Initially, e ..."
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Cited by 113 (12 self)
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In this paper we describe a hierarchical face clustering algorithm for triangle meshes based on fitting primitives belonging to an arbitrary set. The method proposed is completely automatic, and generates a binary tree of clusters, each of which fitted by one of the primitives employed. Initially, each triangle represents a single cluster; at every iteration, all the pairs of adjacent clusters are considered, and the one that can be better approximated by one of the primitives forms a new single cluster. The approximation error is evaluated using the same metric for all the primitives, so that it makes sense to choose which is the most suitable primitive to approximate the set of triangles in a cluster. Based on this approach, we implemented a prototype which uses planes, spheres and cylinders, and have experimented that for meshes made of 100k faces, the whole binary tree of clusters can be built in about 8 seconds on a standard PC. The framework here described has natural application in reverse engineering processes, but it has been also tested for surface denosing, feature recovery and character skinning.
Randomized Cuts for 3D Mesh Analysis
"... The goal of this paper is to investigate a new shape analysis method based on randomized cuts of 3D surface meshes. The general strategy is to generate a random set of mesh segmentations and then to measure how often each edge of the mesh lies on a segmentation boundary in the randomized set. The re ..."
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Cited by 60 (2 self)
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The goal of this paper is to investigate a new shape analysis method based on randomized cuts of 3D surface meshes. The general strategy is to generate a random set of mesh segmentations and then to measure how often each edge of the mesh lies on a segmentation boundary in the randomized set. The resulting “partition function” defined on edges provides a continuous measure of where natural part boundaries occur in a mesh, and the set of “most consistent cuts ” provides a stable list of global shape features. The paper describes methods for generating random distributions of mesh segmentations, studies sensitivity of the resulting partition functions to noise, tessellation, pose, and intraclass shape variations, and investigates applications in mesh visualization, segmentation, deformation, and registration.
Consistent Segmentation of 3D Models
 Computers 01/04/2010 81 K3D D1.4.1 & Graphics, IEEE SMI 2009 proceedings, (33)3
, 2009
"... This paper proposes a method to segment a set of models consistently. The method simultaneously segments models and creates correspondences between segments. First, a graph is constructed whose nodes represent the faces of every mesh, and whose edges connect adjacent faces within a mesh and correspo ..."
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Cited by 54 (5 self)
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This paper proposes a method to segment a set of models consistently. The method simultaneously segments models and creates correspondences between segments. First, a graph is constructed whose nodes represent the faces of every mesh, and whose edges connect adjacent faces within a mesh and corresponding faces in different meshes. Second, a consistent segmentation is created by clustering this graph, allowing for outlier segments that are not present in every mesh. The method is demonstrated for several classes of objects and used for two applications: symmetric segmentation and segmentation transfer. Key words: Mesh segmentation, Mesh analysis 1.
4Points Congruent Sets for Robust Pairwise Surface Registration
 INTERNATIONAL CONFERENCE ON COMPUTER GRAPHICS AND INTERACTIVE TECHNIQUES
, 2008
"... We introduce 4PCS, a fast and robust alignment scheme for 3D point sets that uses wide bases, which are known to be resilient to noise and outliers. The algorithm allows registering raw noisy data, possibly contaminated with outliers, without prefiltering or denoising the data. Further, the method ..."
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Cited by 48 (2 self)
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We introduce 4PCS, a fast and robust alignment scheme for 3D point sets that uses wide bases, which are known to be resilient to noise and outliers. The algorithm allows registering raw noisy data, possibly contaminated with outliers, without prefiltering or denoising the data. Further, the method significantly reduces the number of trials required to establish a reliable registration between the underlying surfaces in the presence of noise, without any assumptions about starting alignment. Our method is based on a novel technique to extract all coplanar 4points sets from a 3D point set that are approximately congruent, under rigid transformation, to a given set of coplanar 4points. This extraction procedure runs in roughly O(n2 + k) time, where n is the number of candidate points and k is the number of reported 4points sets. In practice, when noise level is low and there is sufficient overlap, using local descriptors the time complexity reduces to O(n + k). We also propose an extension to handle similarity and affine transforms. Our technique achieves an order of magnitude asymptotic acceleration compared to common randomized alignment techniques. We demonstrate the robustness of our algorithm on several sets of multiple range scans with varying degree of noise, outliers, and extent of overlap.
Globfit: Consistently fitting primitives by discovering global relations
 ACM Trans. on Graphics
"... Figure 1: Starting from a noisy scan, our algorithm recovers the primitive faces along with their global mutual relations, when are then used to produce a final model (all lengths in mm). ..."
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Cited by 42 (12 self)
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Figure 1: Starting from a noisy scan, our algorithm recovers the primitive faces along with their global mutual relations, when are then used to produce a final model (all lengths in mm).
Illustrating How Mechanical Assemblies Work
, 2010
"... How things work visualizations use a variety of visual techniques to depict the operation of complex mechanical assemblies. We present an automated approach for generating such visualizations. Starting with a 3D CAD model of an assembly, we first infer the motions of individual parts and the inter ..."
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Cited by 39 (7 self)
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How things work visualizations use a variety of visual techniques to depict the operation of complex mechanical assemblies. We present an automated approach for generating such visualizations. Starting with a 3D CAD model of an assembly, we first infer the motions of individual parts and the interactions between parts based on their geometry and a few user specified constraints. We then use this information to generate visualizations that incorporate motion arrows, frame sequences and animation to convey the causal chain of motions and mechanical interactions between parts. We present results for a wide variety of assemblies.
Jointaware Manipulation of Deformable Models
"... Figure 1: Two representative models that users can interactively manipulate within our deformation system. (a) (column 1:) A desk lamp connected by revolute joints, and its colorcoded components. The lampshade is manipulated with the same handle trajectory for three cases: (column 2:) jointunaware ..."
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Cited by 35 (3 self)
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Figure 1: Two representative models that users can interactively manipulate within our deformation system. (a) (column 1:) A desk lamp connected by revolute joints, and its colorcoded components. The lampshade is manipulated with the same handle trajectory for three cases: (column 2:) jointunaware deformation has difficulty facing the lampshade backward because of immovable joints, and links are bent unnaturally(131 cells). (column 3:) jointaware deformation with fully rigid links(6 cells). (column 4:) jointaware deformation with two deformable links in the middle(76 cells). (b) An Aibolike robot dog with a soft tail, a soft body, and two soft ears interactively posed to walk and stand up. (b) Complex mesh models of manmade objects often consist of multiple components connected by various types of joints. We propose a jointaware deformation framework that supports the direct manipulation of an arbitrary mix of rigid and deformable components. First we apply slippable motion analysis to automatically detect multiple types of joint constraints that are implicit in model geometry. For singlecomponent geometry or models with disconnected components, we support userdefined virtual joints. Then we integrate manipulation handle constraints, multiple components, joint constraints, joint limits, and deformation energies into a single volumetriccellbased space deformation problem. An iterative, parallelized GaussNewton solver is used to solve the resulting nonlinear optimization. Interactive deformable manipulation is demonstrated on a variety of geometric models while automatically respecting their multicomponent nature and the natural behavior of their joints.
Nonhomogeneous resizing of complex models
 ACM Trans. Graph
, 2008
"... Figure 1: Resizing a clock model (267 connected components): Standard nonuniform scale distorts the shape of parts of the model, e.g. the dial (b). Our approach resizes the clock in a more natural manner protecting its shape (c). (d) and (e) show part of the protective grid before and after resizin ..."
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Cited by 33 (6 self)
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Figure 1: Resizing a clock model (267 connected components): Standard nonuniform scale distorts the shape of parts of the model, e.g. the dial (b). Our approach resizes the clock in a more natural manner protecting its shape (c). (d) and (e) show part of the protective grid before and after resizing. Resizing of 3D models can be very useful when creating new models or placing models inside different scenes. However, uniform scaling is limited in its applicability while straightforward nonuniform scaling can destroy features and lead to serious visual artifacts. Our goal is to define a method that protects model features and structures during resizing. We observe that typically, during scaling some parts of the models are more vulnerable than others, undergoing undesirable deformation. We automatically detect vulnerable regions and carry this information to a protective grid defined around the object, defining a vulnerability map. The 3D model is then resized by a spacedeformation technique which scales the grid nonhomogeneously while respecting this map. Using spacedeformation allows processing of common models of manmade objects that consist of multiple components and contain nonmanifold structures. We show that our technique resizes models while suppressing undesirable distortion, creating models that preserve the structure and features of the original ones.
MinCut Based Segmentation of Point Clouds
"... foreground points from background clutter. (For easier visualization, points are drawn with colors representing their heights) We present a mincut based method of segmenting objects in point clouds. Given an object location, our method builds a knearest neighbors graph, assumes a background prior, ..."
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Cited by 33 (2 self)
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foreground points from background clutter. (For easier visualization, points are drawn with colors representing their heights) We present a mincut based method of segmenting objects in point clouds. Given an object location, our method builds a knearest neighbors graph, assumes a background prior, adds hard foreground (and optionally background) constraints, and finds the mincut to compute a foregroundbackground segmentation. Our method can be run fully automatically, or interactively with a user interface. We test our system on an outdoor urban scan, quantitatively evaluate our algorithm on a test set of about 1000 objects, and compare to several alternative approaches. 1.