![Page 1: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/1.jpg)
Direct Geometry Processing for Tele-
Fabrication
Yong Chen*, Kang Li#, Xiaoping Qian#
* Epstein Department of Industrial and Systems Engineering,
University of Southern California, Los Angeles, CA 90089
# Department of Mechanical, Materials and Aerospace Engineering,
Illinois Institute of Technology, Chicago, IL
2012 CIE Conference, Chicago, IL
Aug. 13, 2012
![Page 2: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/2.jpg)
CONTENTS
Introduction of 3D tele-fabrication
3D data acquisition
Geometry processing
Point cloud slicing
Support generation
Mask image planning
Fabrication results and discussion
Summary
2
![Page 3: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/3.jpg)
2D Faxing
2D Scanning (Chicago) Printing (Los Angeles) 3
![Page 4: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/4.jpg)
2D Faxing Processing
4
![Page 5: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/5.jpg)
5
3D Scanners
• Zcorp• Makebot 3D
replicator• NextEngine• 3Shape• HDI 3D
Scanner• etc.
![Page 6: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/6.jpg)
6
3D Printers
• Cubify• VFlash• Perfactory• ZCorp• Objet• Projet• uPrint• etc.
![Page 7: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/7.jpg)
7
3D Faxing
• An open question: how should geometry be processed in future 3D faxing systems?
Points
Polygonal meshes(STL)
3D Scanners 3D Printers?
Geometry processing
![Page 8: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/8.jpg)
3D Tele-fabrication overview
Point cloud slicing
Support generation
Mask image planning
3D Scanning (Chicago)
Manufacturing(Los Angeles)
8
Geometry processing
![Page 9: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/9.jpg)
Geometry processing flowchart
Physical object
Scanned point data
Sliced contours
Support structure
Manufactured model
Chicago Los Angeles
9
![Page 10: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/10.jpg)
Data acquisition
Computer3D digitizer
Rotary stage
Object
Digitizing system 6-step range image scanning
10
![Page 11: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/11.jpg)
Point cloud slicing overview
Point cloudMorse function and
MLS surfaceCritical points and
Morse-Smale complex
Enhanced Reeb graphSliced model
11
![Page 12: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/12.jpg)
Moving Least Square (MLS) surface
Normal vector field
qxv
qxvxn
i
i
iNi
iNi
),(
),()(
qx
qx
qx
i
j
i
h
h
iNe
e2
2
/
/
),(
Energy function
Qqqyxnqyxny
iiNi
Tiie ),()()())(,(
2
ix
0x
1ix
nx
S )(, iil xnx
))(,( ie xny
Implicit definition stationary set of a projection operator
})(|{ 3 xxx pRS
Energy function and normal vector field
MLS surface point with local minimum energy
( , ( ))( ) ( ) 0T e
g
y x
y n xx n x
y
MLS explicit definition
12
![Page 13: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/13.jpg)
Critical points
01)(
2
x
x
x
xx
g
g
f
f
Morse function f: height value
φ on MLS
Critical points identified by:
Slicing contour topology controlled by critical points
4 types of critical points Contour topology
13
![Page 14: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/14.jpg)
Morse-Smale complex and enhanced Reeb graph
MS complex: integral lines tracing
Enhanced Reeb graph: MS complex re-organizing
Grouping / Pruning
Morse-Smale (MS) complex: tracing integral lines
from saddles to maximum/minimum Enhanced Reeb graph: graph processing of MS complex
14
![Page 15: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/15.jpg)
Enhanced Reeb graph as contour marching start
Slicing planeIntersection with
enhanced Reeb graphContour marching from
intersected point
Sliced model: all raised contours stacked
15
![Page 16: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/16.jpg)
Curvature-adaptive contour marching
Contour marching by intersection Curvature-adaptive step size
Point subset near the slicing plane Adaptive contour points generation
Step size determined by osculating radius
16
![Page 17: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/17.jpg)
Support generation based on contours
17
• Supports are required to ensure the success of the 3D printing process• No drifting/floating away;• Reduce deformation due to shrinkage.
Flat Bottom
Cantilever
Floating Overhang
Vaulted Overhang
Cantilever
Ceiling
![Page 18: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/18.jpg)
Contour-based support generation principle
Two consecutive layer contours
Support structure analysis
18
![Page 19: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/19.jpg)
Support generation algorithms
Previous layer A
Current layer B
C = A ∩ B
A
B A
B
D = C offset by r
r
1
23 Sself = D ∩ B
4 Sanchor = B - Sself
Sanchor : anchor-support region
Sself : self-support region
A
19
![Page 20: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/20.jpg)
Anchor-support region covering
B
A
B
A
Input regionsSupport layout by region covering
CAD model of supports
(Contours based)
CAD model of support by Lightyear system
(STL based)
20
![Page 21: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/21.jpg)
Support generation examples
Point cloud
Sliced model
Support structure
21
![Page 22: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/22.jpg)
Layer ID 1 100 200 300
Mask image planning: Image projection of layers
Mask image of part
Mask image of support
Projection mask image
22
![Page 23: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/23.jpg)
Fabrication example
Point cloud Sliced model Fabricated model
23
(1)
(2)
![Page 24: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/24.jpg)
Manufacturing compatibility with different layer thickness
24
Macro-
Meso-
Micro-
![Page 25: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/25.jpg)
Summary
• Tele-fabrication is critical for future product
design and manufacturing
• Developed a tele-fabricating approach by
integrating 3D scanning and printing
• Presented a direct geometry data flow method in
such an integration system
• Performed physical experiments to verify the
effectiveness of the direct geometry method.
25
![Page 26: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/26.jpg)
Acknowledgments
• National Science Foundation CMMI-0927397 (USC).
• National Science Foundation CMMI-0900597 and CMMI-1030347 (IIT)
26
![Page 27: Direct Geometry Processing for Tele-Fabrication Yong Chen *, Kang Li #, Xiaoping Qian # * Epstein Department of Industrial and Systems Engineering, University](https://reader036.vdocuments.site/reader036/viewer/2022062801/56649e5d5503460f94b56b92/html5/thumbnails/27.jpg)
Questions?
27