Automatic Extraction of Three Dimensional Prismatic ...ijcscn.com/Documents/Volumes/vol1issue3/ijcscn2011010315.pdf · Automatic Extraction of Three Dimensional Prismatic Machining

Automatic Extraction of Three Dimensional Prismatic Machining

Features from CAD Model B.V. Sudheer Kumar*, C.S.P. Rao**

*Research Scholar, Dept. of Mechanical Engineering, NIT Warangal, A.P, India-506021

[email protected] **Professor, Dept. of Mechanical Engineering, NIT Warangal, A.P, India-506021

[email protected]

Abstract

Machining features recognition provides the necessary

platform for the computer aided process planning

(CAPP) and plays a key role in the integration of

computer aided design (CAD) and computer aided

manufacturing (CAM). This paper presents a new

methodology for extracting features from the

geometrical data of the CAD Model present in the form

of Virtual Reality Modeling Language (VRML) files.

First, the point cloud is separated into the available

number of horizontal cross sections. Each cross section

consists of a 2D point cloud. Then, a collection of

points represented by a set of feature points is derived

for each slice, describing the cross section accurately,

and providing the basis for a feature-extraction. These

extracted manufacturing features, gives the necessary

information regarding the manufacturing activities to

manufacture the part. Software in Microsoft Visual

C++ environment is developed to recognize the

features, where geometric information of the part is

extracted from the CAD model. By using this data, an

output file i.e., text file is generated, which gives all the

machinable features present in the part. This process

has been tested on various parts and successfully

extracted all the features.

1. Introduction

The term feature does not imply the same meaning

in different engineering disciplines. This has resulted in

several ambiguous definitions for feature. A feature, in

Computer Aided Design (CAD) software, can be called

a region of a part with some interesting geometric or

topological patterns. This meaning can refer to all sorts

of information, such as for example, shape, functional

or manufacturing information. Although many types of

features have been investigated, the most common type

of feature is the form feature, which contains both

shape information and parametric information.

Examples of form features common in many shape

models are round holes, slots, steps and pockets.

Features can also be used to represent manufacturing

information of the part. Different manufacturing

domains require different feature representations. Some

of the properties that need to be encoded by features are

assembly method, manufacturing process and

tolerances. A manufacturing feature can be defined as a

form feature, but not necessarily vice versa. Among

manufacturing features, the ones received extensive

attention is the machining features. A machining

feature can be regarded as the volume swept by a

cutting tool. In this sense, it is always a negative

(subtracted) volume, in contrast with form features that

are sometimes positive (added) volumes.

Feature data in a CAD model can be represented

either as a collection of surfaces or volumes. Surface

features are naturally used for example to describe

manufacturing tolerances or locating surfaces in fixture

design. Volumetric features on the other hand, are used

in process planning since manufacturing information

(particularly in machining) is better portrayed

volumetrically.

Most of the parts can be interpreted in terms of

machining features i.e., holes, steps, slots and pockets.

Computer Aided Process Planning (CAPP) will use

these features to generate manufacturing instructions to

produce the part. Jung Hyun Han [4] made a survey on

feature recognition and merits of several algorithms of

feature recognition i.e. graph pattern matching, cell

based decomposition, convex hull decomposition and

Hint based reasoning etc. Mike Pratt and William C.

Regli [3] gave an overview on the three major

algorithmic approaches for feature recognition and

B V Sudheer Kumar et al, International Journal of Computer Science & Communication Networks,Vol 1(3), 285-296

285

ISSN:2249-5789

mentioned several drawbacks of them. In the graph-

based algorithms, the part is represented by a graph

data structure, and is searched for particular patterns for

features. The volumetric decomposition approach

decomposes the volume of the part to be manufactured

into a set of intermediate volumes and then manipulates

the volumes to produce features. The hint-based

reasoning starts from a minimal indispensable portion

of a feature's boundary which should be present in the

part, and performs extensive geometric reasoning. Joshi

and Chang [5] developed a graph named the Attribute

Adjacency Graph (AAG) to represent features in which

each face of the part is represented as a node, and each

edge or face adjacency is represented as an arc.

Sashikumar Venkataraman [6] presented a graph based

frame work for feature recognition. The feature

recognition step involved finding similar sub graphs in

the part graph. The novelty of this framework lied in

the usage of a rich set of attributes to recognize a wide

range of features efficiently. W.F. Lu [7] gave an

approach to recognize features from a data exchanged

part model. A litany of algorithms for the identification

of design and machining features are proposed. Emad

S. Abouel Nasr [8] discussed a methodology for

extracting manufacturing features from CAD system.

The system takes a neutral file in Initial Graphics

Exchange Specification (IGES) format as input and

translates the information in the file to manufacturing

information. The boundary (B-rep) geometrical

information of the part is then analyzed by a feature

recognition program that is created specifically to

extract the features from the geometrical information

based on a geometric reasoning approach.

The basic role of the CAD is to precisely define the

geometry of the product, as it is critical to all the

subsequent activities in the product life cycle. In most

of the cases parts are designed in separate CAD

environments, which have no direct link with

manufacturing. Different CAD packages use different

types of database structures to store the information of

the part in a CAD file. In this paper CATIA V5R16 is

used for modeling the part. However other CAD soft

wares, which have an option to convert CAD data, file

into Virtual Reality Modeling Language (VRML)

format can also be used. After developing the CAD

model VRML file will be generated.

2. Virtual Reality Modeling Language

VRML, sometimes pronounced vermal, is an

acronym for the Virtual Reality Modeling Language.

Technically speaking, VRML is neither virtual reality

nor a modeling language. Virtual reality typically

implies an immersive 3D experience (such as a head-

mounted display) and 3D input devices (such as digital

gloves). VRML neither requires nor precludes

immersion. Furthermore, a true modeling language

would contain much richer geometric modeling

primitives and mechanisms. VRML provides a bare

minimum of geometric modeling features and contains

numerous features far beyond the scope of a modeling

language [17].

VRML can most easily be seen as a 3D interchange

format that supports common features such as

hierarchical transformations, light sources, geometry,

animations, visual effects, material properties and

texture mapping. VRML has been designed to be an

analog to the commonly used HTML, in that it is a

multi-platform language for publishing web content in

a relatively simple and straight-forward way.

2.1. The structure of VRML [18]

A VRML file consist of the following main sections

2.1.1. Header

The header of the file tells the VRML parser that the

file is an actual VRML file of a certain version, along

with the file´s encoding type. It has the following

format:

#VRML V2.0 utf8 [optional comment] <line

terminator>

2.1.2. Scene Graph

The scene graph contains nodes which describe

objects and their properties. It contains hierarchically

grouped geometry to provide an audio-visual

representation of objects, as well as nodes that

participate in the event generation and routing

mechanism.

2.1.3. Prototypes

A Prototype is a node type created by the user by

providing extensions to the standard set of nodes. A

prototype can be seen as the struct data type in ANSI C,

or as a macro.

2.1.4. Event Routes

Some VRML nodes generate events in response to

environmental changes or user interaction. Event routes

provide the creator of a scene means of catching these


286

ISSN:2249-5789

events and route them into other nodes that respond to

these events.

2.1.5. Script Nodes

Script nodes are nodes used to catch and process

events from other nodes. By using Scripts, more

advanced functions can be achieved, rather than just the

sheer passing of messages that is done by the event

routing.

2.2. The VRML browser [19]

The VRML files created are interpreted and

presented by the browser. The browser can be either a

stand-alone application or a plug-in for an ordinary web

browser such as Internet Explorer. The browser

presents the geometry of the VRML scene graph along

with means of interacting, navigating and exploring the

virtual world.

The main components of the browser are the Parser,

the Scene graph and the Presentation modules. The

Parser reads the VRML file and constructs the

hierarchical structure of transformations and geometry

nodes comprising the scene graph from this

information. The presentation module renders the scene

graphically and audibly back to the user.

3. Development of Feature Recognition

Module from CAD Model

The part modeled using the CAD forms the basis for

the extraction of the features. .In this paper CATIA

V5R16 is used for modeling the component. The output

file is generated in the VRML format. Software has

been developed using the Visual C++ which can extract

the geometrical entities like surfaces, edges and

vertices.

The IndexedFaceSets of VRML file provide the

information, such as sets of coordinate points, color

values and normal vectors to identify faces, edges and

vertices. Then the automatic feature extraction

algorithm extracts all the details of the prismatic

features present. The details include type of feature,

location of the feature and necessary dimensions related

to the feature. The major features considered in this

paper are holes, steps, slots, islands and pockets. An

output file (text file) will be generated, which contains

the list of features with dimensions. The Feature

Recognition Module is clearly explained with examples

in the following section.

3.1. Feature extraction methodology

The CAD model has been developed using “CATIA

V5R16” software. From the developed CAD model

Virtual Reality Modeling Language (VRML) file is

generated. This serves as necessary input file for

feature extraction. Any CAD software, which is having

the provision of generating the VRML file can be used

for generating the model. The shape node of VRML

file contains two inner nodes, namely Appearance and

geometry IndexedFaceSet. Among those two, the

geometry IndexedFaceSets will provide the necessary

geometrical information, such as coordinate point sets

to identify faces (surfaces), edges (lines) and vertices

(points).

From the VRML file, all the points (vertices) have to

be identified.

All the lines (edges) have to be defined from the

previously identified points.

In any VRML file, the height of the object will be

measured along Y-axis, hence the y coordinate

difference of the top plane and bottom plane always

indicates the height of the part.

The point cloud is then divided into number of

horizontal planes. The number of planes will be exactly

equal to the number of different y coordinate values.

3.1.1. Hole

The hole of the CAD model in VRML file has been

represented by circular top face, circular bottom face

and two semicircular lateral surfaces. The semicircular

lateral surfaces are used to identify the diameter, x and

z coordinates of the center. The top and bottom points

of the semi circular lateral surface can be segregated

into two sets based on y coordinate value.

Procedure to find the diameter: Consider the two sets

separately, and find minimum x value and maximum x

value. The diameter can be obtained directly as the

difference of these two values.

Procedure to find the center X coordinate: the x

coordinate of the center can be obtained as the average

of minimum and maximum x values.

Procedure to find the center Z coordinate: the z

coordinate of either minimum x or maximum x can be

considered as the center Z coordinate.


287

ISSN:2249-5789

Through Hole: if two circles with same center and

diameter, present on top and bottom planes, it indicates

presence of a through hole feature. The height of the

hole is same as the height of the part

Blind Hole: if two circles with same center and

diameter, present on top and intermediate planes, it

indicates presence of a blind hole feature. The height of

the hole is same as the difference of y coordinates of

the two planes on which the two circles are present.

Stepped Hole: if four circles are identified with same

center, and two circles with diameter D1 and the other

two with diameter D2, the height of the step1 is same

as the difference of y coordinates of the two planes on

which the two circles are present and the height of the

step2 is same as the difference of y coordinates of the

two planes on which these two circles are present.

If the sum of heights of step1 and step2 is equal to the

height of the part, the feature is stepped through hole,

else stepped blind hole

3.1.1. Blind slot The corner points on the planes F1 (top plane) and F7

(bottom plane) have to be compared considering F7 as

reference. If all the four corner points are present, and

one of the edges of top plane should have two

discontinuous lines, and the points of the top plane

except corner points should be matched with the points

of an intermediate plane, then it indicates presence of

blind slot.

Fig 1 Schematic Diagram Showing Blind Slot

The dimensions can be calculated as below.

The depth can be calculated s the distance between the

edges E9 and E7.

The length can be calculated as the distance between

the edges E11 and E8.

The width can be calculated as the distance between the

edges E10 and E13.

3.1.2. Slot

The corner points on the planes F1 (top plane) and F7


reference. If all the four corner points are present, and

two opposite edges of top plane should have two

discontinuous lines, and the points of the top plane

except corner points should be matched with the points

of an intermediate plane, then it indicates presence of a

slot.


The depth can be calculated as the distance between the

edges E3 and E6.

The length is equal to the length of the object.


edges E3 and E12.

Fig 2 Schematic Diagram Showing Slot

3.1.3. Blind step

The corner points on the planes F1 (top plane) and F7


reference. If any one corner is missing, and the

remaining three corner points are present, it indicates

presence of blind step at the missing corner point. In


288

ISSN:2249-5789

the above figure the corner point exactly above V11 or

V9 is missing.



edges (E4 and E10) or (E5 and E11)




edges E10 and E13.

Fig 3 Schematic Diagram Showing Blind Step

Horizontal step: Compare the edges of top plane (F1)

with the bottom reference plane (F7). If any horizontal

edge is missing, it indicates the presence of horizontal

step


edges E3 and E6.



The width is equal to the width of the object.

Vertical step: Verify all the four vertical edges of the

part. If any vertical edge is missing, it indicates the

presence of vertical step.

The depth is equal to the height of the object.

The length can be calculated as the distance


edges E9 and E8.

Fig 4 Schematic Diagram Showing Horizontal Step

Fig 5 Schematic Diagram Showing Vertical Step

3.1.4. Pocket

Pocket: Verify all the four edges of the top plane with

respect to bottom plane edges. If all the edges are

found, and if the vertices on plane F1 except the corner

points are present on any one of the intermediate

planes, it indicates the presence of pocket.


edges E6 and E11




289

ISSN:2249-5789


edges E6 and E7.

Fig 6 Schematic Diagram Showing Pocket

3.1.5. Island

Verify all the four edges of the top plane with respect to

bottom plane edges. If all the edges are missing, and all

the vertices on plane F1 are present on any one of the

intermediate planes, it indicates the presence of island.


edges E5 and E9




edges E6 and E7.

4. Case Study

In this section, the prismatic machining features of an

example part have been extracted with the help of the

developed automatic feature extraction software. The

details of which are explained in the following sections.

4.1. CAD module

This module represents the CAD environment with

functions for designing and visualization of the part.

The functions of this CAD module are to allow the user

to design the part in 3D and make changes if any, in the

design of the part. The example part i.e. the plate with

various features has been modeled in CATIA is shown

in Fig 8. Any other CAD package like Pro-E, IDEAS

can also be used. The generated output file (VRML

file) is given as input to the feature recognition module.

Fig 7 Schematic Diagram Showing Island

Fig 8 CAD Module

4.2. Feature extraction from the VRML file

This module represents the Feature extraction from

the VRML file of the part. The module is developed in

Visual C++ environment (refer to Fig. 9).


290

ISSN:2249-5789

Fig 9 The Feature Recognition Module in the Visual

C++ environment.

The coordinates are grouped so that they represent the

features altogether. The function of the feature

extraction module is to extract the coordinates which

represent the features present in the part from the

VRML file generated form the CAD module. The

VRML file is converted into text file which has the list

of features.

This output is given as input for the next module.

The following file shows the output file for the given

problem.

OUTPUT

Below are the circles identified

Center (x:y:z): (30.000000 : 0.000000 : -30.000000) ,

Diameter : 20.000000

Center (x:y:z): (-20.000000 : 0.000000 : -40.000000) ,


Center (x:y:z): (10.000000 : 10.000000 : 40.000000) ,


Center (x:y:z): (30.000000 : 30.000000 : -30.000000) ,


Center (x:y:z): (30.000000 : 30.000000 : -30.000000) ,


Center (x:y:z): (10.000000 : 40.000000 : 40.000000) ,


Center (x:y:z): (-20.000000 : 40.000000 : -40.000000) ,


Center (x:y:z): (30.000000 : 40.000000 : -30.000000) ,


Blind Hole

Center of the hole is 10.000000 : 40.000000

Height of the hole is 30.000000

Diameter of the hole is 24.000000

Center (x,y,z) - Diameter

(10.000000:10.000000:40.000000) - 24.000000


(10.000000:40.000000:40.000000) - 24.000000

Through Hole

Center of the hole is -20.000000 : -40.000000




(-20.000000:0.000000:-40.000000) - 18.000000


(-20.000000:40.000000:-40.000000) - 18.000000

Stepped Hole

Center of the hole is 30.000000 : -30.000000




(30.000000:0.000000:-30.000000) - 20.000000


(30.000000:30.000000:-30.000000) - 20.000000


(30.000000:30.000000:-30.000000) - 40.000000


(30.000000:40.000000:-30.000000) - 40.000000

Before processing for steps below are the planes

identified.

Vertices of Plane 40.000000

Boundaries (x,z) (Min, Max) -- (70.000000:-

100.000000), (-60.000000:60.000000)

Non vertex Points are 20

vertex (x:z): 70.000000 : 60.000000

vertex (x:z): 70.000000 : 20.000000

vertex (x:z): 70.000000 : -60.000000

vertex (x:z): 70.000000 : 0.000000

vertex (x:z): -40.000000 : -60.000000

vertex (x:z): -40.000000 : 0.000000

vertex (x:z): -40.000000 : 20.000000

vertex (x:z): -40.000000 : 60.000000

vertex (x:z): -60.000000 : 60.000000

vertex (x:z): -60.000000 : -60.000000

vertex (x:z): -60.000000 : 0.000000

vertex (x:z): -60.000000 : 20.000000

vertex (x:z): -70.000000 : 60.000000

vertex (x:z): -70.000000 : 40.000000

vertex (x:z): -80.000000 : -30.000000


291

ISSN:2249-5789

vertex (x:z): -80.000000 : -60.000000

vertex (x:z): -100.000000 : 40.000000

vertex (x:z): -100.000000 : -30.000000

vertex (x:z): -100.000000 : 0.000000

vertex (x:z): -100.000000 : 20.000000

Vertex Points are 0


Boundaries (x,z) (Min, Max) -- (-70.000000:-

100.000000), (40.000000:60.000000)


vertex (x:z): -70.000000 : 40.000000

vertex (x:z): -70.000000 : 60.000000

vertex (x:z): -100.000000 : 40.000000

vertex (x:z): -100.000000 : 60.000000 -- BOUNDARY

Vertex Points are 1



100.000000), (-60.000000:60.000000)


vertex (x:z): 70.000000 : 20.000000

vertex (x:z): 70.000000 : 0.000000

vertex (x:z): -40.000000 : -60.000000

vertex (x:z): -40.000000 : 0.000000

vertex (x:z): -40.000000 : 20.000000

vertex (x:z): -40.000000 : 60.000000

vertex (x:z): -60.000000 : -60.000000

vertex (x:z): -60.000000 : 60.000000

vertex (x:z): -60.000000 : 0.000000

vertex (x:z): -60.000000 : 20.000000

vertex (x:z): -100.000000 : 0.000000

vertex (x:z): -100.000000 : 20.000000

Vertex Points are 0



100.000000), (-60.000000:-30.000000)


vertex (x:z): -80.000000 : -60.000000

vertex (x:z): -80.000000 : -30.000000

vertex (x:z): -100.000000 : -60.000000 --

BOUNDARY

vertex (x:z): -100.000000 : -30.000000

Vertex Points are 1


Boundaries (x,z) (Min, Max) --

(100.000000:70.000000), (-60.000000:60.000000)


vertex (x:z): 100.000000 : -60.000000 -- BOUNDARY

vertex (x:z): 100.000000 : 60.000000 -- BOUNDARY

vertex (x:z): 70.000000 : 60.000000

vertex (x:z): 70.000000 : -60.000000

Vertex Points are 2



(100.000000:100.000000), (-60.000000:60.000000)




Vertex Points are 2

No Step on the right side

No Step on the bottom side

No Step on the top side

After processing for Max Z steps

Below are the Planes identified



100.000000), (-60.000000:60.000000)


vertex (x:z): 70.000000 : 60.000000

vertex (x:z): 70.000000 : 20.000000

vertex (x:z): 70.000000 : -60.000000

vertex (x:z): 70.000000 : 0.000000

vertex (x:z): -40.000000 : -60.000000

vertex (x:z): -40.000000 : 0.000000

vertex (x:z): -40.000000 : 20.000000

vertex (x:z): -40.000000 : 60.000000

vertex (x:z): -60.000000 : 60.000000

vertex (x:z): -60.000000 : -60.000000

vertex (x:z): -60.000000 : 0.000000

vertex (x:z): -60.000000 : 20.000000

vertex (x:z): -70.000000 : 60.000000

vertex (x:z): -70.000000 : 40.000000

vertex (x:z): -80.000000 : -30.000000

vertex (x:z): -80.000000 : -60.000000

vertex (x:z): -100.000000 : 40.000000

vertex (x:z): -100.000000 : -30.000000

vertex (x:z): -100.000000 : 0.000000

vertex (x:z): -100.000000 : 20.000000

Vertex Points are 0



100.000000), (40.000000:60.000000)


vertex (x:z): -70.000000 : 40.000000

vertex (x:z): -70.000000 : 60.000000

vertex (x:z): -100.000000 : 40.000000


Vertex Points are 1



100.000000), (-60.000000:60.000000)


vertex (x:z): 70.000000 : 20.000000

vertex (x:z): 70.000000 : 0.000000

vertex (x:z): -40.000000 : -60.000000

vertex (x:z): -40.000000 : 0.000000

vertex (x:z): -40.000000 : 20.000000

vertex (x:z): -40.000000 : 60.000000


292

ISSN:2249-5789

vertex (x:z): -60.000000 : -60.000000

vertex (x:z): -60.000000 : 60.000000

vertex (x:z): -60.000000 : 0.000000

vertex (x:z): -60.000000 : 20.000000

vertex (x:z): -100.000000 : 0.000000

vertex (x:z): -100.000000 : 20.000000

Vertex Points are 0



100.000000), (-60.000000:-30.000000)


vertex (x:z): -80.000000 : -60.000000

vertex (x:z): -80.000000 : -30.000000

vertex (x:z): -100.000000 : -60.000000 --

BOUNDARY

vertex (x:z): -100.000000 : -30.000000

Vertex Points are 1



(70.000000:70.000000), (-60.000000:60.000000)




Vertex Points are 2



(70.000000:100.000000), (-60.000000:60.000000)




Vertex Points are 2

No steps in the plane 40.000000

Before processing for Blind Steps

No Blind Step on the Bottom Left Corner

No Blind Step on the Bottom Left Corner

No steps in the plane 40.000000

Before processing for Slots

START OF THROUGH SLOT

X, Y, Z co ordinates in terms of Range (MIN , MAX)

X co ordinate is -40.000000 60.000000

Y co ordinate is 22.000000 40.000000

Z co ordinate is -60.000000 60.000000

X, Y, Z co ordinates in terms of vertices

-40.000000 40.000000 -60.000000

-60.000000 40.000000 -60.000000

-60.000000 40.000000 -60.000000

-40.000000 40.000000 -60.000000

-40.000000 22.000000 -60.000000

-60.000000 22.000000 -60.000000

-60.000000 22.000000 60.000000

-40.000000 22.000000 60.000000

<------------------END--------------->

START OF BLIND SLOT


X co ordinate is -60.000000 -100.000000

Y co ordinate is 22.000000 40.000000

Z co ordinate is 0.000000 20.000000


-60.000000 40.000000 0.000000

-100.000000 40.000000 0.000000

-100.000000 40.000000 20.000000

-60.000000 40.000000 20.000000

-60.000000 22.000000 0.000000

-100.000000 22.000000 0.000000

-100.000000 22.000000 20.000000

-60.000000 22.000000 20.000000

<------------------END--------------->

START OF BLIND SLOT


X co ordinate is 70.000000 -40.000000

Y co ordinate is 22.000000 40.000000

Z co ordinate is 0.000000 20.000000


70.000000 40.000000 0.000000

-40.000000 40.000000 0.000000

-40.000000 40.000000 20.000000

70.000000 40.000000 20.000000

70.000000 22.000000 0.000000

-40.000000 22.000000 0.000000

-40.000000 22.000000 20.000000

70.000000 22.000000 20.000000

<------------------END--------------->

START OF BLIND STEP


X co ordinate is -70.000000 -100.000000

Y co ordinate is 25.000000 40.000000

Z co ordinate is 40.000000 60.000000


-70.000000 40.000000 40.000000

-100.000000 40.000000 40.000000

-100.000000 40.000000 60.000000

-70.000000 40.000000 60.000000

-70.000000 25.000000 40.000000

-100.000000 25.000000 40.000000

-100.000000 25.000000 60.000000

-70.000000 25.000000 60.000000

<------------------END--------------->

START OF BLIND STEP



293

ISSN:2249-5789

X co ordinate is -80.000000 -100.000000

Y co ordinate is 20.000000 40.000000

Z co ordinate is -60.000000 -30.000000


-80.000000 40.000000 -60.000000

-100.000000 40.000000 -60.000000

-100.000000 40.000000 -30.000000

-80.000000 40.000000 -30.000000

-80.000000 20.000000 -60.000000

-100.000000 20.000000 -60.000000

-100.000000 20.000000 -30.000000

-80.000000 20.000000 -30.000000

<------------------END--------------->

START OF THROUGH STEP


X co ordinate is 100.000000 70.000000

Y co ordinate is 18.000000 40.000000

Z co ordinate is -60.000000 60.000000


100.000000 40.000000 -60.000000

70.000000 40.000000 -60.000000

70.000000 40.000000 60.000000

100.000000 40.000000 60.000000

100.000000 18.000000 -60.000000

70.000000 18.000000 -60.000000

70.000000 18.000000 60.000000

100.000000 18.000000 60.000000

<------------------END--------------->

After processing for Slots

Below are the Planes identified


Boundaries (x,z) (Min, Max) –

(70.000000:-100.000000), (-60.000000:60.000000)


vertex (x:z): -100.000000 : -60.000000

vertex (x:z): -100.000000 : 60.000000

vertex (x:z): 70.000000 : -60.000000

vertex (x:z): 70.000000 : 60.000000

Vertex Points are 2



(-70.000000:-100.000000), (40.000000:60.000000)



Vertex Points are 1



(70.000000:-100.000000), (-60.000000:60.000000)


Vertex Points are 0



(-80.000000:-100.000000), (-60.000000:-30.000000)


vertex (x:z): -100.000000 : -60.000000

Vertex Points are 1



(70.000000:70.000000), (-60.000000:60.000000)




Vertex Points are 2



(70.000000:100.000000), (-60.000000:60.000000)




Vertex Points are 2

5. Conclusions

This paper proposes a novel approach towards the

integration of CAD and CAPP. The geometrical data

obtained from a CAD model is utilized to extract the

three dimensional features. A program in Visual C++

environment is being used to extract the features from

VRML file. The list of features can be obtained in an

output text file By using this approach manufacturing

feature recognition of components can be done using

VRML file format.

References

[1] Nafis Ahmad, and A.F.M. Anwarul Haque.,

“Manufacturing feature recognition of parts Using

DXF file”, 4th International Conference on

Mechanical Engineering, December 2001, Dhaka,

Bangladesh. pp. 111-115.

[2] T. Dereli, and H. I. Filiz, “Optimization of Process

Planning functions by Genetic algorithm”,

Computers and Industrial Engineering, 1999, Vol.

36, pp. 281-308.

[3] Mike Pratt and William C. Regli, “Manufacturing

Feature Recognition from Solid Models: A Status

Report”, IEEE transactions on robotics and

automation, 2000, vol. 16, no. 6, pp. 782-796.

[4] Jung Hyun Han, “Survey on Feature Research,

Institute for Robotics and Intelligent systems”,

USC, USA, 1996. (Technical report IRIS-96-346)

[5] S. Joshi, and T. C. Chang, “Graph Based

Heuristics for Recognition of Machined Features


294

ISSN:2249-5789

from 3D Solid Model”, Computer Aided Design,

1988, Vol. 20, pp. 58-66.

[6] Sashikumar Venkataraman, “A Graph based Frame

work for Feature recognition”, ACM 2001 1-

58113-366-9/01/06, 2001.

[7] W.F. Lu, “An approach to identify design and

manufacturing features from data exchanged part

model”, Computer-Aided Design, 2003, Vol. 35,

pp. 979–993.

[8] Emad S. Abouel Nasr, “A new methodology for

extracting manufacturing features from CAD

system”, Computers & Industrial Engineering,

2006, Vol. 51, pp. 389–415.

[9] Murata Tadao, “Petri Nets: Properties, Analysis

and applications”. IEEE Transactions on Electrical

Engineering and Computer Science, 1989.

[10] K. Srihari, and C. R. Emerson, “Petri nets in

dynamic process planning”, Computers &

Industrial Engineering, 1990, Vol. 19, pp. 447–

451.

[11] J. A. Cecil, C. R. Emerson, K. Srihari, “A review

of Petri net applications in process planning”,

International Journal of Advanced Manufacturing

Technology, 1992 , Vol. 7, pp. 168–177.

[12] P. Xirouchakis and D. Kiritsis, “A generic Petri net

model for disassembly planning processes”,

presented at TMCE’96, Budapest, 1996

[13] D. Kiritsis and M. Porchet, “A generic Petri net

model for dynamic process planning and sequence

optimization”. Adv. Engineering Software, 1996,

Vol. 25, No. 1, pp. 61–71.

[14] D. Kiritsis, K. P. Neuendorf, and P. Xirouchakis,

“Petri net techniques for process planning cost

estimation”, Advances in Engineering Software,

1999, Vol. 30, pp, 375–387.

[15] J. M. Usher, and R. O. Bowden, “The application

of genetic algorithms to operation sequencing for

use in computer-aided process planning”,

Computers & Industrial Engineering, 1996, Vol.

30, No.4, pp. 999-1013.

[16] H.B.Marri, A. Gunasekaran, and R. J. Grieve,

“Computer aided process planning: A state of art

survey”, International journal of Manufacturing

Technology, 1998, Vol. 14, pp. 261-268.

[17] Ramesh Naidu Ande, “Integrated VRML, JAVA,

XML and HTML in a web based tool”, SCSC,

2004.

[18] Don Brutzman, “The Virtual Reality Modeling

Language and Java, Communications of the

ACM”, 1998, vol. 41 no. 6, pp. 57-64.

[19] Kian-Huat Tan, Tze Leong Yew, and Kurt

Gramoll, “Understanding Machine Operations and

Manufacturing using VRML”, Am. Soc. of

Engineering Educ, (ASEE) 1999 Conf., June 20 -

23, Charlotte, NC, 1999.

[20] Anil Sawhney, Andre Mund, and Jennifer Marble,

“Simulation of the Structural Steel Erection

Process”, Proceedings of the 31st Winter

Simulation Conference, 1999.

[21] WD Version 0.9.0, “Software and Systems

Engineering – High-level Petri Nets Part 2:

Transfer Format”, International Standard ISO/IEC

15909-2 June 23, 2005.


295

ISSN:2249-5789

APPENDIX-A: Solid Model of the Part Used to Extract the Features


296

ISSN:2249-5789