Part Sourcing in a global market

(A 3D Internet Search Engine)

Dr Jonathan Corney (Engineering),

Dr Doug Clark (Mathematics),

Mr Micheal Breaks (Library),

Dr Heather Rea (Research Associate),

Heriot-Watt University

How many components exist?• 6 Billion People on the planet.• Currently 20 Billion CAD models! (AutoDesk).• Online databases of over 1 Million mechanical

CAD models (www.inpart.com) PTC.• We guess between 60 to 600 Billion distinct

designs?• How many are moulding, pressings or castings?• How many have 3D CAD representations?

Research Vision

“One day, soon, engineers will be able to search the Internet for 3D models which are geometrically similar to ones they have designed on their CAD system.”

The scenarioA CAD model of a prototype part is exported in

a neutral format (VRML,STL).The part is uploaded to a 3D search engine

which presents the engineer with a list of the most geometrically similar parts in its database.

The engineer can change the design to use the existing part or get the supplier to quote for supply of the new component.

Our Goal

Why will this be useful ?

Because the modification, or re-use, of existing parts is far quicker, and cheaper, than starting from scratch:

$1 to $5 million a year saving through the re-use of plastic clips in one Automotive company (Berchtold 1992).

Aggressive reuse of parts could reduce the cost of complex systems by 20% (Cybenko 1996),

Why will this be useful ?

Potentially it’s a win-win scenario !

• The designers get cheaper parts,faster.

• The manufacturers get to sell to a bigger market and re-sell existing “inventory”.

So potentially everyone wins from the re-use of existing molds, dies, jigs, fixtures, CNC code and CAD data etc.

Why not ?Cost too much ?

Internet economics suggest it will cost nothing.

People will steal the 3D CAD data ?Exact CAD data not required (VRML,STL).

Computers can’t tell if shapes are similar ?True! This is the research.

IPR and contracts will be too complicated?Also part of the research.

3 Year, EPSRC Funded Project

£170K From EPSRC over 3 years from June 00

Support in “cash and kind” from 3 collaborators: Pathtrace.net,

(CAD/CAM Software & Internet Services)

Subcontract UK Ltd,(Manufacturing Yellow Pages, www.firstindex.com)

Scottish Polymer Technology Network,(Industry Focus, Business Issues)

Project Plan

1st Year Plan: – Baseline Measurement of Human Performance.– Stand alone geometric similarity algorithms.– Build-up Collections of 3D Models (test data).– Initiate Business Issues Study.– Upload Server.

Indexing the database Searching the database

Database

GeometricAnalysis Program

Search Engine

Web Page

Upload Page

Search Engine GUI

GeometricAnalysis Program

Results Display

Part Number:L3567Desc: Lock pinMaterial: Steel 535Strength: 5 N/m2

: :

Looking for:

Found:84%

79%

52%

3D Model

Picture

Material

Surface Area

Volume

Indices

FilenameC:/models/l3546

Steel535Material

Name

Owner

Lock pin

Locksmiths PLC

Upload FileC:/temp/newpart

polypropeleneMaterial

Scale

Email address

3:1

Me@here.com

Java3D Prototype

Plan for Similarity Algorithms

3 year plan to implement progressively more exact shape indexes:

•Size: Bounding Boxes, Bounding Spheres, Number of Facets.

•Physical Properties: Volume, Surface Area, Moments, Crinkliness, Fractal Dimension, Medial Surface.

•Normalization:Position, Scale & Orientation.

•Spatial Occupancy: Voxel Comparisons

Crinkliness*

The `crinkliness' of a faceted model is defined as the surface area of the model divided by the surface area of a sphere having the same volume as the model:

Crinkliness = sphere

model

SArea

SArea

*Denis Mollison (1972) `Conjecture on the spread of infection in two dimensions disproved', Nature 240, 467-468.

Fractal Dimension Fractal Dimension (D)

indicates the degree of detail in an object and how much space it occupies between the Euclidean dimensions:

• It has often been applied as a measure of 2D surface roughness and boundary shape.

• An increase in D represents an increase in complexity.

• But even in 2D significant differences in complexity only contribute to slight differences in D (20%).

Basic Concepts of Fractal Dimension 2D Fractal Dimension is

determined by calculating either the area, or length of a profile, over a range of resolutions. There are many approaches:

• One common method measures the lengths or distances between points on the border.

• Another method counts border pixels located within discs of various diameter, where the discs are randomly centered on the border.

Parallel-Planes Method for Calculating Fractal Dimension

Estimates the volume of a model by summing the “swept area” of a number of intersection planes:

• Horizontal flat planes are specified at regular intervals with pitches ranging from 1 to 50 units.

• Intersected area is calculated by intersecting a plane and the model.

• All intersected area multiplied by the pitch and summed to give a total volume. The process is repeated for all pitch sizes.

Results and Comparisons

0.08110.08140.08150.0782D6 (method 6)

0.07780.06810.06580.0662D5 (method 5)

0.07060.07100.07110.0689D4 (method 4)

0.08600.08150.09290.0851D3 (method 3)

0.07350.07370.07370.0714D2 (method 2)

1.02681.02441.02361.0223D1 (method 1)

8.90712.84633.02081.1713Crinkliness

542 095672 925803 7551,000,000Volume (units3)

128,583153,434170,47460,000Surface area (units3)

11,9256,4934,5286No. of polygons

3220126No. of primitives

Tri-DiceDuo-DiceMono-DiceSimple Cube

Normalization

• Normalization is needed to allow voxel-voxel comparisons.

• Position: Centroid located at the origin.

• Size: Scale to fit standard size.

• Orientation: Rotation applied to the object to align it with the principle moments.

Voxel Comparisons

Test Data

Physical PropertiesModel diag_len mx/mn md/mn area(A) volume(V) A/V

sh-r44372-000-u 60.3 0 10.0 0 1.1 1 4701 0 2650 0 0.61797609in 129.8 1 10.0 0 1.1 1 13020 0 19194 0 1.5

sh-r44369-000-u 27.7 0 4.6 0 1.1 1 409 0 128 0 0.3ex25 132.7 1 3.0 0 3.0 0 25883 1 72668 0 2.8

GABracket1 4.0 0 1.7 1 1.6 1 24 0 2 0 0.1ex03 330.7 0 12.3 0 1.8 0 136525 0 929372 0 6.8

Holes5 71.4 0 5.0 0 1.0 1 9945 0 20091 0 2.0HookClamp3 90.5 1 1.9 1 1.3 1 13372 0 35089 0 2.6

ex44 271.3 0 6.0 0 2.0 0 109768 0 856001 0 7.8ex24 183.3 0 4.0 0 2.0 0 43292 0 228883 0 5.3

good-coupling 320.2 0 1.3 0 1.0 1 192010 0 2209883 0 11.5ex02 201.5 0 1.7 1 1.5 1 97473 0 877627 0 9.0

good-bracket 179.2 0 5.3 0 2.1 0 35235 1 195766 0 5.6ex43 174.4 0 3.0 0 1.0 1 59255 0 430284 0 7.3ex06 257.7 0 4.5 0 1.0 1 84447 0 756552 0 9.0

edgesupport 127.1 1 1.9 1 1.0 1 34187 1 204045 0 6.0goodpart3 164.0 0 2.4 1 1.2 1 48583 0 365529 0 7.5goodpart1 164.0 0 2.4 1 1.2 1 48609 0 369273 0 7.6

ex42 140.0 1 3.0 0 2.0 0 33998 1 217425 0 6.4good-die 206.2 0 2.7 0 1.5 1 84337 0 852996 0 10.1

handknob1 47.1 0 1.8 1 1.0 1 4731 0 11333 0 2.4E2part 73.0 0 1.4 1 1.3 1 10900 0 45000 0 4.1ex01 173.2 0 1.0 0 1.0 1 74754 0 821926 0 11.0el3 500.8 0 2.4 1 1.0 1 330284 0 12099302 0 36.6

sphere 346.4 0 1.0 0 1.0 1 125664 0 4188790 0 33.3bone 107.7 1 2.0 1 1.3 1 27724 1 134432 1 4.8

Matrix Model dl x/n d/n x/d/n A V A/V c A/B X Y Zsh-r44372-000-u 0 0 1 0 0 0 0 0 1 0 0 0 0.411797609in 1 0 1 0 0 0 0 1 0 0 0 0 0.50

sh-r44369-000-u 0 0 1 0 0 0 0 1 0 0 0 0 0.41ex25 1 0 0 1 1 0 0 1 1 0 1 0 0.71 close

GABracket1 0 1 1 0 0 0 0 1 0 0 0 0 0.50ex03 0 0 0 0 0 0 0 1 1 0 0 0 0.41Holes5 0 0 1 0 0 0 1 1 1 0 0 0 0.58

HookClamp3 1 1 1 0 0 0 1 1 0 0 0 0 0.65ex44 0 0 0 1 0 0 1 1 1 0 0 0 0.58ex24 0 0 0 1 0 0 1 1 0 1 1 0 0.65

good-coupling 0 0 1 0 0 0 1 1 0 0 0 0 0.50ex02 0 1 1 0 0 0 1 1 1 0 0 0 0.65

good-bracket 0 0 0 0 1 0 1 1 0 1 0 0 0.58ex43 0 0 1 1 0 0 1 1 1 0 0 0 0.65ex06 0 0 1 1 0 0 1 1 0 0 0 0 0.58

edgesupport 1 1 1 1 1 0 1 1 1 0 0 1 0.87 closegoodpart3 0 1 1 0 0 0 1 1 1 0 0 0 0.65goodpart1 0 1 1 0 0 0 1 1 1 0 0 0 0.65ex42 1 0 0 1 1 0 1 1 1 0 0 0 0.71 close

good-die 0 0 1 0 0 0 1 1 1 0 0 0 0.58handknob1 0 1 1 0 0 0 1 1 1 0 0 0 0.65E2part 0 1 1 0 0 0 1 1 1 0 0 0 0.65ex01 0 0 1 0 0 0 1 1 1 0 0 0 0.58el3 0 1 1 0 0 0 0 1 0 0 0 0 0.50

sphere 0 0 1 0 0 0 0 0 0 0 0 0 0.29bone 1 1 1 1 1 1 1 1 1 1 1 1 1 close

Results

Target Model “Bone”

> 0.7

>= 0.65

Results

Target Model “Botfig8”

> 0.7

> 0.65

> 0.55

What is the “correct” answer?

?

?

Human PerformanceChoose the five most similar objects to the circled one.

Business Issues

Lots of Questions:

• Does the commissioner of a part get a royalty every time it is reused ?

• Could contractors manufacture components for less in return for “reuse rights”?

• Are there existing models which could be adopted to support this sort of trading (Project Alba’s VCX)?

Project Plan

2nd Year Plan– Incorporation of similarity algorithms into an

on-line search engine.– First User trials.– Development of more sophisticate tests for

geometric similarity (normalization).– Business Issues Report

Project Plan

3rd Year Plan– Large Scale Trials (1000+ parts).– Yet more sophisticated measures of geometric

similarity (voxel comparisons).– On-line prototype.– Full developed business model for trading and

re-use of mechanical components .

Why am I telling you this?

We need: Lots of 3D Models (in VRML or STL

format). People to do take the online similarity tests.

Next year feedback on the prototype.

Closing thoughtIf commercial 3D Search Engines appear within the next five years, will commercial pressures force CAD models of almost every manufactured part to be post on the Internet by 2010 ?