|
|
Pinghai Yang
Illinois Institute of Technology 243 Engineering One Building Tel: 312-5673772 Email: |
About
Me:
I am a Ph.D. student in Department of Mechanical, Materials &
Aerospace Engineering at Illinois Institute
of Technology. I work with Prof.
Xiaoping Qian and I am a member of the Computational
Design and Manufacturing Lab. Before that, I spent seven years in Huazhong University of Science and
Technology and got my M.S. and B.E. in mechanical engineering.
Research
Interests:
Developing new algorithms for product design,
analysis and manufacturing from acquired point cloud. A major goal of this
research is to develop computational tools enabling a new way of developing
products, direct design and manufacturing from 3D sensing of pre-existing objects,
one that can bypass the painstaking CAD model reconstruction involved in
current product development process.
Publications:
|
|
Adaptive Slicing of Moving Least Squares Surfaces:
Toward Direct Manufacturing from Point Cloud Data Yang, P. and Qian, X. ASME Transactions Journal of Computing and
Information Science in Engineering. Accepted. Abstract: Rapid advancement of 3D sensing
techniques has lead to dense and accurate point cloud of an object to be
readily available. The growing use of such scanned point sets in product
design, analysis and manufacturing necessitates research on direct processing
of point set surfaces. In this paper, we present an approach that enables the
direct layered manufacturing of point set surfaces. This new approach is
based on adaptive slicing of moving least squares (MLS) surfaces. Salient
features of this new approach include: 1) it bypasses the laborious surface
reconstruction and avoids model conversion induced accuracy loss; 2) the
resulting layer thickness and layer contours are adaptive to local curvatures
and thus it leads to better surface quality and more efficient fabrication;
3) The curvatures are computed from a set of closed formula based on the MLS
surface. The MLS surface naturally smoothes the point cloud and allows
up-sampling and down-sampling, and thus it is robust even for noisy or sparse
point sets. Experimental results on both synthetic and scanned point sets are
presented. |
|
|
Direct computing of
surface curvatures for point-set surfaces Yang, P. and Qian, X. Proceedings of 2007 IEEE/Eurographics
Symposium on Point-based Graphics(PBG), Abstract: Accurate computing of the curvatures of
a surface from its discrete form is of fundamental importance for many
graphics and engineering applications. The moving least-squares (MLS) surface
from Levin [Lev2003] and its variants have been successfully used to define
point-set surfaces in a variety of point cloud data based modeling and
rendering applications. This paper presents a set of analytical
equations for direct computing of surface curvatures from point-set surfaces
based on the explicit definition from [AK Our experimental validation on both
synthetic and real point cloud data demonstrates that such direct computing
from analytical equations provides a viable approach for surface curvature
evaluation for unorganized point cloud data. |
|
|
A B-spline based
Approach to Heterogeneous Object Design and Analysis Yang, P. and Qian,
X. Computer-Aided Design, Vol. 34, No. 2, pp. 95
-111, Feb 2007. Abstract: The recent advancement of solid
freeform fabrication, design techniques and fundamental understanding of
material properties in functionally graded materials has made it possible to
design and fabricate multifunctional heterogeneous objects. In this paper, we
present an integrated design and analysis approach for heterogeneous object
realization, which employs a unified design and analysis model based on B-spline representation and allows for direct interaction
between the design and analysis model without laborious meshing operation. In
the design module, a new approach for intuitively modeling multi-material
objects, termed heterogeneous lofting, is presented. In the analysis module,
a novel graded B-spline finite element solution
procedure is described, which gives orders of magnitude better convergence
rate in comparison with current methods, as demonstrated in several case
studies. Further advantages of this approach include simplified mesh
construction, exact geometry/material composition representation and easy
extraction of iso-material surface for
manufacturing process planning. |
|
|
Computing Admissible
Transformation Volume Qian, X. and Yang P. ASME Design Engineering Technical Conferences,
CA, Sept 2005. Abstract: The ability to quantify
part dimensional quality with respect to design specifications is of
fundamental importance in product design and manufacturing. Our earlier work
has proposed the use of admissible transformation volume as a part
dimensional quality metric. That is, part quality is quantified based on how
much an as-manufactured part shape can move while still remaining within a
tolerance zone. A transformation is admissible if upon such a transformation
a manufactured part shape falls within the design tolerance zone. A
collection of such transformations in the transformation space forms an
admissible transformation volume (ATV). In this paper, we present two
properties of ATV: transformation invariant and decomposability. We then
describe algorithms for computing ATV and how ATV properties facilitate
complex tolerance check and reveal new insight on part producibility. |
Personal:
Here is link to my Personal website.
Updated on May
1st, 2008