Publications
Shuffler: Modeling with Interchangeable Parts
V. Kraevoy D. Julius A. Sheffer
To appear in Visual Computer journal, 2007
Abstract:
Following the increasing demand to make the creation
and manipulation of 3D geometry simpler and more accessible,
we introduce a modeling approach that allows even
novice users to create sophisticated models in minutes. Our
approach is based on the observation that in many modeling
settings users create models which belong to a small
set of model classes, such as humans or quadrupeds. The
models within each class typically share a common component
structure. Following this observation, we introduce
a modeling system which utilizes this common component
structure allowing users to create new models by shuffling
interchangeable components between existing models. To
enable shuffling, we develop a method for computing a compatible
segmentation of input models into meaningful, interchangeable
components. Using this segmentation our system
lets users create new models with a few mouse clicks,
in a fraction of the time required by previous composition
techniques. We demonstrate that the shuffling paradigm allows
for easy and fast creation of a rich geometric content.
Links: Paper
(pdf)
Virtual Garments: A Fully Geometric
Approach for Clothing Design
Philippe Decaudin, Dan Julius, Jamie Wither, Laurence Boissieux, Alla
Sheffer, Marie-Paule Cani
Eurographics 2006
Abstract:
Modeling dressed characters is known as a very
tedious process. It usually requires specifying 2D fabric patterns,
positioning and assembling them in 3D, and then performing a
physically-based simulation. The latter accounts for gravity and
collisions to compute the rest shape of the garment, with the adequate
folds and wrinkles.
This paper presents a more intuitive way to design virtual clothing. We
start with a 2D sketching system in which the user draws the contours
and seam-lines of the garment directly on a virtual mannequin. Our
system then converts the sketch into an initial 3D surface using an
existing method based on a precomputed distance field around the
mannequin. The system then splits the created surface into different
panels delimited by the seam-lines. The generated panels are typically
not developable. However, the panels of a realistic garment must be
developable, since each panel must unfold into a 2D sewing pattern.
Therefore our system automatically approximates each panel with a
developable surface, while keeping them assembled along the seams. This
process allows us to output the corresponding sewing patterns.
The last step of our method computes a natural rest shape for the 3D
garment, including the folds due to the collisions with the body and
gravity. The folds are generated using procedural modeling of the
buckling phenomena observed in real fabric. The result of our algorithm
consists of a realistic looking 3D mannequin dressed in the designed
garment and the 2D patterns which can be used for distortion free
texture mapping. The patterns we create also allow us to sew real
replicas of the virtual garments.
Links: Paper
(pdf) BibTex
Material Aware Mesh Deformations
T. Popa D. Julius A. Sheffer
SMI 2006, ACM SIGGRAPH 2005 ? Poster (ACM Student Research Competition
winner)
Abstract:
Most real world objects consist of non-uniform
materials; as a result, during deformation the bending and shearing are
distributed non-uniformly and depend on the local stiffness of the
material. In the virtual environment there are three prevalent
approaches to model deformation: purely geometric, physically driven,
and skeleton based.
This paper proposes a new approach to model deformation that
incorporates non-uniform materials into the geometric deformation
framework. Our approach provides a simple and intuitive method to
control the distribution of the bending and shearing throughout the
model according to the local material stiffness. Thus, we are able to
generate realistic looking, material-aware deformations at interactive
rates. Our method works on all types of models, including models with
continuous stiffness gradation and non-articulated models such as
cloth. The material stiffness across the surface can be specified by
the user with an intuitive paint-like interface or it can be learned
from a sequence of sample deformations.
Links: Paper
(pdf) Abstract
(pdf) Poster
(ppt) Slides
(ppt) BibTex
D-Charts: Quasi-Developable Mesh Segmentation
D. Julius V. Kraevoy A. Sheffer
Eurographics 2005
Abstract:
Quasi-developable mesh segmentation is required for
many applications in graphics and CAD, including texture atlas
generation and the design of patterns for model fabrication from sheets
of material. In this work we introduce D-Charts, a simple
and robust algorithm for mesh segmentation into (nearly) developable
charts. As part of our method we introduce a new metric of
developability for mesh surfaces. Thanks to this metric, using our
segmentation for texture atlas generation, we can bound the distortion
of the atlas directly during the segmentation stage. We demonstrate
that by using this bound, we generate more isometric atlases for the
same number of charts compared to existing state-of-the-art techniques.
Using our segmentation algorithm we also develop a technique for
automatic pattern design. To demonstrate the practicality of this
technique, we use the patterns produced by our algorithm to make fabric
and paper copies of popular computer graphics models.
Links: Paper
(pdf) Slides
(ppt) FF
Slides (ppt) BibTex
Other work (I'm also proud of)
Developable Surface Processing Methods for
Three-Dimensional Meshes
D. Julius
MSc
Thesis (pdf)
Real Toys from Virtual Models
D. Julius V. Kraevoy A. Sheffer
SIGGRAPH 2005, Making Graphics Real sketch session
Abstract:
The design of patterns for sewing 3D objects is a
time honored art based on rules developed over generations. In this
work we introduce an algorithm for automatic pattern design which
focuses on patterns for soft, stuffed toys. To demonstrate the
viability of the technique, we use the patterns produced by our
algorithm to make real fabric copies of popular computer graphics
models. Motivated by the papercraft toys developed in [Mitani and
Suzuki:04], we created an algorithm suitable for use with fabric. In
contrast to paper, fabric, for the most part, can be slightly
stretched, allowing a less restrictive approach when defining the
sewing patterns. As part of our method, we introduce a new metric of
developability for mesh surfaces and show how to use this metric to
segment surfaces into (nearly) developable patches. A surface patch is
developable if it may be isometrically mapped (i.e., unfolded) onto the
plane. These patches play a key role in our method since we want to
minimize the distortion created when unfolding them into planar
patterns which are then sewn together to form the 3D model. As a
compact developable segmentation does not typically exist, we allow
patches to be nearly developable based on user prescribed tolerances.
Links: Sketch
(pdf) Slides
(ppt) Bunny
sewing charts Gumby sewing
charts
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