CAD (Assignment I)

8/2/2019 CAD (Assignment I)

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Technological Educational Institute of Piraeus

MSc ADVANCED INDUSTRIAL AND

MANUFACTURING SYSTEMS

Module: Integrated CAD/CAM

Assignment:

The Future of CAD/CAM A Speculative Paper

Module Leader: Prof. Dr.-Ing. Constantinos STERGIOU

Students Name: Georgios G. ROKOS

Students Signature: ___________________________

Date: May 2011


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Technological Professional Institute of Piraeus

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This paper has its origins in the Integrated CAD/CAM Module of the MSc in

Advanced Industrial and Management Systems, undertaken at the

Technological Educational Institute of Piraeus, in cooperation with the

Kingston University, under the aegis of Dr. Constantinos Stergiou.

This assignment revolves around CAD modeling concepts, focusing on

parametric and direct modelers. It explicitly presents the philosophy and the

differences between those two system types and records the advantages and

disadvantages they carry.

Moreover, this paper occupies with the history of CAD/CAM systems as an

ensemble of techniques and practices. It identifies the functionalities that

they included and the general advantages that they implied with the pass of

time.

Finally, the trends concerning CADs future, as they appear with todays

computer technology, are presented in the final chapter of the paper

All the conclusions recorded in this paper result from the contrast of

Solidworks 2007 and IronCAD 2011 by a novice user of the CAD technology,

with poor engineering background

Hopefully, this paper will be a pleasant experience for its readers.

Georgios Rokos


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PART I .............................................................................................................................. 31. Introduction ............................................................................................................. 3

1.1A glance in history ............................................................................................. 31.2Actual alternatives ............................................................................................. 3

2. Parametric Feature Based modeling VS Direct modeling ........................................... 52.1Uniform, common workspace against separate workspace ................................. 52.2Sketching 2D profiles and implementing features against direct insertion of 3D

parts .................................................................................................................. 5

2.3History-based against History-free modeling ...................................................... 62.4 Constraint-based and free-to-modify modeling ................................................... 6

PART II ............................................................................................................................. 7

1. Development of a back foot ...................................................................................... 72. Development of a front foot ................................................................................... 243. Development of the opposite feet .......................................................................... 264. Development of the first link .................................................................................. 285. Development of the second link ............................................................................. 326. Development of the bottom back holder ................................................................ 337. Development of the top back holder....................................................................... 388. Development of the pillow ..................................................................................... 409. Development of the Chairs Assembly .................................................................... 43

PART III .......................................................................................................................... 46

1. Conclusion and trends ............................................................................................. 47

References..................................................................................................................... 48


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1.1 A glance in history

When Dr. Patrick Hanratty developed PRONTO, the first commercial numerical-control

programming system, in 1957, and MITs PhD student Ivan Sutherland developed

SKETCHPAD three years later, few could predict the expansion of Computer Aided Design in

many productive sectors of modern society.

The initial CAD systems offered, in reality, nothing more than an electronic alternative to

classic hand-made paper drawing. Only 2D sketches could be drawn and pragmatic

productivity met with a subtle increase. In addition, the benefits of the interaction between

engineers and computer systems could not be conceived at that point. The high costs

associated with computer proprietorship delimited the usage of CAD systems to large

corporations and retarded the advent of the new manufacturing era (1).

With the pass of time, companies from the automotive and the aerospace industry started

funding 3D-oriented projects (2). From the beginning of the 60s, 3D wireframe features were

deployed and in 1969 MAGI released the first commercially available 3D solid modeler,

called Syntha Vision.

In the 80s, DECs new VAX minicomputers series and UNIXs open architecture lowered boththe cost and the complexity of computer proprietorship and usage, setting new bounds in

CAD anticipations.

In 1989, NURBS, a mathematical representation of freedom surfaces was unveiled in Silicon

Graphics. Concurrently, Parametric Pro introduced T-Flex, the first parametric CAD for PCs.

In 1993, Unigraphics introduced the first hybrid CAD release, supporting both parametric

and traditional modeling processes.

1.2 Actual alternatives

Despite the technological breakthroughs, older CAD releases are still preferred in specific

sectors due to their unique characteristics. Currently, one may identify eight distinct

categories of CAD systems (3).

1) Traditional 2D Drafting, equipped with a Bill of materials operation.

2) 3D Wireframe/Surface Modeling systems are gradually being replaced, mainly due to

their translation difficulties from other 3D CAD modelers. However, in complex multi-curve

industrial designs that consist of multiple parts, such as airplane designs, Surface Modeling isstill a popular methodology.


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3) 3D Constructive Solid Geometry (CSG) Solid Modeling is used to design parts, instead of a

wireframe outline, that are actually solid objects with volume, weight and mass. The

computer may automatically calculate many physical properties in this case. These

calculations can even for irregularly shaped parts.

CSG applies solid primitives, such as rectangular prisms, and boolean operations, such as

unions and subtractions. Its main deficit is the absence of editing capabilities making

changes a trying process of reconstruction.

4) 3D Boundary Representation (Brep) Solid Modeling starts with wireframe sketching to

create solid models by extruding, sweeping, revolving or skinning the sketch while

supporting boolean operations. Solids can also be developed by combining complex

surfaces through a sewing function.

5) 3D Hybrid Solid Modeling is the combination of CSG and Brep solid modeling methods.

6) 3D Feature-based Solid Modeling enables the association of operations such as creating

holes, fillets with specific edges and faces. Whenever a face is moved, the feature operation

follows the act, maintaining the relationship. Regeneration in this case postulates flawless

feature referencing.

7) 3D Feature-based, Parametric Solid Modeling implies the association of each

entity/operation with operator-defined parameters that monitor its numerous geometric

properties and its locations within the model. Parametric modelers are history-based and,

thence, keep records of building steps.

If the operator alters the parameters and regenerates the part, the program will repeat the

operations from the beginning, implementing the new parameters to create the new solid.

This method is particularly popular when testing a new article.

Some parametric modelers also guesstimate relationships between parameters through

constraint equations, conjecturing value dependencies amongst distinct entities and

parameters.

Finally, parametric modelers include geometric constraints between entities (i.e. tangent,

parallel, etc).

8) 3D Feature-based, Dynamic Solid Modelingis a history-free method that employs flexible

model creation and refinement concepts to allow designers to capture ideas and detail

models quickly. In fact, it allows the development of not fully dimensionally constrained

features.


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As explained in the previous chapter, CAD systems experience fundamental modifications

quite ordinarily. Different systems in structure and operating concept may be found in the

market at the same period, serving the same needs, namely modeling, in a different manner.

Today, the prevailing parametric history-based modelers are believed to be receding in sales

in favor of direct, history-free modeling systems. The latter may be also identified as

dynamic modelers.

In order to illustrate the major differences between the two approaches, the development

of a chair assembly in both systems is presented in the second part of the paper. IronCAD

(direct modeler) and Solidworks (parametric modeler) constitute the examined programs.

2.1 Uniform, common workspace against separate workspaces

From the beginning of the task, the first major discrepancy between Solidworks and IronCAD

one would notice lies in the fact that two systems offer different working environments.

While Solidworks calls for separate workspaces for each component/part of the assembly,

IronCAD allows modeling the assembly directly in one workspace. In Solidworks, each part

needs to be developed in its own environment prior to assembling the total of them in

another environment. IronCAD, on the other hand, permits modeling all parts in one

workspace where the assembling process can take place as well.

2.2 Sketching 2D profiles and implementing features against direct insertion of 3D solid

parts

The development of a part in Solidworks postulates the design of its profile in a 2Dworkspace. The part will then acquire its 3D form through the implementation of specific

features such as Extrude and Revolve Boss Base. To modify the initial shape, a Solidworks

user will need again to return to the 2D profile and sketch the modifications on the surface

involved, prior to applying a feature command. This process is the reason behind the

feature-based label attributed to parametric design modelers such as Solidworks.

Contrary to Solidworks, IronCAD possesses a catalogue of fully rendered 3D shapes. All the

operator needs to do is to drag and drop the requested shape in the workspace and then

insert the 3D dimensions that characterize the part. An IronCAD user may also modify a

shape by dropping on it another shape.


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For instance, if a Solidworks user wishes to add a spherical component on a part, as it

happens in our case with the chairs top, he/she will need to sketch an arc and select the

Revolve Base feature. In IronCAD, dragging and dropping the sphere shape on top of the

cylindrical base, which is one of the chairs back feet, suffices to replace Revolve Base.

2.3 History-based against History-free modeling

Solidworks records the feature commands that are applied during each step of the modeling

process on what is called the History tree. The term History is utilized to describe the

hierarchic dependence that exists among the various features that interact to arrive to the

final form of a part or assembly. The depiction of the recording operation looks like a tree

whose branches are, in fact, the features.

IronCAD, which is not a feature-based system, records the shapes that are combined to

develop each part instead. However, when a feature is to be applied, the program will

record it, the same way Solidworks does. IronCAD does not exclude most of the feature

commands that are available in Solidworks.

A modification of a feature or sketch in Solidworks would lead to a cascade modification of

the related features, causing the model to regenerate or even to collapse. This is the reason

why hierarchy is highlighted by parametric modelers operators. When modifications are to

be applied, the latter have to implement a plan concerning the sequence of the

interventions so that they can all be applicable.

2.4 Constraint-based and free-to-modify modeling

Another major discrepancy between Solidworks and IronCAD lies beneath the inclusion of

constraints during the models development.

As aforementioned, Solidworks is based on a 2D environment to commence the deployment

of a part. The sketches that are drawn in this environment define the part whose

components are final in terms of positioning and dimensioning. Thus, geometric constraints

burden the modifications an operator may attempt to implement.

Contrarily, IronCAD and other explicit modelers enable the dynamic intervention of the

operator to the part and its components.

For instance, if an IronCAD user wishes to displace a socket on a part, he will simply drag it

to a new position or insert directly the geometrical values that characterize the position. A

Solidworks user will need to select the surface and go back to the sketch to insert the new

positioning constraints, causing the part to regenerate.

At this point, it is worth mentioning that IronCAD does allow the operator to insert

positioning and geometrical constraints and to lock certain specifications but this is not adefault option.


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1.1The principal characteristic of the chairs back feet is a cylinder. To create the cylinder in

SD, a plane was selected to sketch a circle (Radius = 40 mm), and the Extruded Boss Base

feature was applied to the sketch to add material towards an under definition direction and

for an under definition distance.

Figure 1

To develop the same shape in IC, the Catalogue Browser was turned on by selecting View

Catalogue Browser. Then, in the Shapes panel of the Browser, a number of basic solid shapes

were available for dragging and dropping into the workspace. Figure 2 illustrates both the

Shapes panel and the shape Cylinder that was just dragged and dropped into the

workspace.


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Figure 2

By right clicking on one of the red spots of the shape, the Edit Sizebox option was

available. This option enabled the determination of both the radius and the Extrusion depth

of what would be a circle in SW. Length and width are one and the same, namely the circles

radius, since the shape is a cylinder. Modifying one of them automatically generates the

modification of the second. Height is the extrusion depth.

Figure 3


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1.2 Post to the formation of the cylinder, slot cuts needed to be created on the surface of

the part. In SW, to do so, the right plane was selected and a rectangle was sketched. Then,

dimensions called for determination while positioning constraints needed to be inserted. In

order to place the slot cut right in the middle of the shapes right plane-view, the distance of

at least one the vertical lines from the centerline needed specification. So did the rectangles

bottom horizontal line from the origin. Having defined the sketch, the extrusion surface and

the depth had to be fixated, as shown in Figure 4

Figure 4

When the Cut-Extrude feature was applied, the Linear Pattern feature was utilized to place a

copy of the first Slot Cut on top, at an under definition distance from the first shape. The

Linear Pattern features elaboration is shown in Figure 5.


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Figure 5

In IC, developing the Slot Cuts was believed to be far less trying. By selecting the right

camera from the Camera Picker (Figure 6), the workspace was positioned on what would be

in SD the right plane and view concurrently.

Figure 6

The rotating surface was then clicked on three times to turn the editing level to Surface.


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Subsequently, the H Slab shape was selected from the Catalogue

Browser and dropped right onto the middle of the shape (in terms

of width).

The system understood that the centerpoint of the new shape

was supposed to be placed literally on the Z axis, that is at a null

value on the X axis. What remained to be determined was the

distance from the origin on the Z axis. By activating the Position

Dimensions option (View Position Dimensions), as in Figure 7, the

distances of the H Slab from the origin appeared on the workspace.

Right clicking on the distances enabled their edition.

Figure 8 demonstrates the automatically determined null distance

from the origin in terms of the X axis.

Once the position was specified, the dimensions (size) of the Slotcut remained to be determined. At the IntelliShape editing level of

the H Slab, by right clicking on one of the red handles it was possible

to Edit the Sizebox. Figure 10 depicts the insertion of the

dimensions of the solid which replaced the Cut Extrude feature.

Figure 7

ery time a shape is clicked on in

nCAD, its editing status/level

itches.

ere are three editing levels:

rt editing level, when the shape is

played in a cyan blue outline

gure 13).

elliShape editing level, when the

ape is displayed in a yellow

tline and red handles appear in

e middle of the part (Figure 3).

rface editing level, when the

ected surface appears in green

gure 40).


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Figure 8

Figure 9

Thought the system understood by itself that the extrusion was supposed to commence

from the surface of the cylinder, it was always possible to right click on H Slab at the Scene

Browser, a table similar to the History Tree of Solidworks, and apply positioning and shape

constraints (start and end constraints, draft, etc). Figure 10 illustrates from a roundabout

camera the edition of the H Slab.


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Figure 10

Instead of applying the Linear Pattern feature at first, a second H Slab was dragged and

dropped from the Catalogue Browser to develop the second Slot Cut. Although the Cuts

seemed to be linearly placed, with no between each other, it turned out they were not

when assembling the parts later on.

1.3 To insert a sphere on Top of the Cylinder in SW, at first, the height of the cylinder

needed to be corrected/diminished. A small circle was sketched on the top face and was cut

extruded (Figure 11). The smaller cylinder would be auxiliary, helping determine the position

of the sphere and the other shapes that were to be included along it.

On the front plane, a semicircle was sketched from the top of the new cylinder and

downwards. Then the Revolve Bose Base feature was applied (Figure 12).


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Figure 11

Figure 12


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In IC, to apply the above corrections, at first the height of the first cylinder was diminished

by the same amount as that of the depth of the cut extrusion in SW, while a new cylinder

was dragged and placed on top the large cylinder, at the midpoint (Figure 13).

Figure 13

The dimensions were inserted as in the previous steps. Then a sphere was dragged and

dropped right onto the green spot that signalized the origin from the top camera (Figure 14).

What remained to be adjusted were the dimensions and the distance from the bottom of

the large cylinder, using the same methods as in the previous steps.

Figure 14


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1.4The following step was the development of what in IC is called torus, as well as fillets

(identified as Blends in IC).

To create a Torus in SW, a semicircle needs to be sketched and then the Revolve Boss Base

feature needs to be applied, as in Figures 15 and 18. To fillet an edge, the Fillet feature

needs to be applied to the selected edge/face. Figures 16 and 17 demonstrate the

application of the Fillet feature. Note that a new extrusion was performed to add a medium

sized cylinder between the small and large one, after sketching a circle on the top face of the

large cylinder.

Figure 15

Figure 16


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Figure 17

Figure 18

To perform the same interventions in IC, first the new cylinder was added as in the previous

step (Figure 19), then the edges were blended (Figure 20) and, finally, two Toruses were

dragged and dropped on top of the part (from the Top Camera), right on the point that

signalized the center point of the cylinders.


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When dropping the Toruses, they were placed above the part but by changing their position

in the Z axis, through editing an in Figure 21, they would be transported to the required

position. Figures 22 and 23 demonstrate the final result in both SW and IC.

Figure 19

Figure 20


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Figure 21

Figure 22


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Figure 23

1.5 The following step was the creation of the remaining slot cuts. Two cuts needed to be

placed to the right of the existing cuts and another two needed to be positioned above the

latter. The same mistaken processes were followed again, as in step 1.2.

1.6 After finishing the slot cuts, an aesthetic intervention was added near the middle of the

cylinder, in terms of height. To complete the

In Solidworks, a new plane was introduced, parallel to the top plane and at a distance of

570mm (Figure 24). Then on the new plane, a small circle was sketched and Cut Extruded to

remove material for some distance along the cylinder (Figure 25). This was done to free

some space/material so that three semicircles could be sketched. The Revolve Boss Base

feature was then applied to the sketch (Figure26).


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Figure 24

Figure 25


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Figure 26

To accomplish the same result with IC, two Toruses were dropped right on the centerpoint

of the cylinders (from the Front Camera) and their distances from the origin (in terms of

height) were adjusted. Since the program did not have any option to co-relate the Toruses

(make them equal), their size-dimensions were inserted separately. Then an H-Torus was

also dragged and dropped while its dimensions and its position were adjusted after those inSolidworks (Figure 27).

Figure 27


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Having completed the part in both modelers the following major differences have been

noticed:

a)

While in SW forming a solid component implies the selection of a plane, a 2D sketchand the application of a feature, in IC all it takes is dropping a predefined solid

component and adding its positioning and dimensioning parameters, always within

the 3D working environment.

b) In SW, sketches and features may be correlated while in IC they cannot. Forinstance, by diminishing the radius of the large cylinder in Figure26 (SW), the toruses

would follow the surface of the regenerated cylinder as during the sketching of their

semicircles, the endpoints of the sketches were set to be coincident to the surface of

the cylinder. The same change in IC, would lead the toruses to float around the

regenerated cylinder, as no coincident constraint was available.

c) In SW, it takes more than one plane to complete a model while in IC there is onlyone workspace.


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Component part 2: Development of a front foot

The front foot consists of a cylinder, four slot cuts and a fillet on top of the cylinder. Its

modeling process is similar to the previous one in both systems. Nevertheless, it is worth

mentioning that while in SW the front foot needed to be modeled at a separate file/working

space, in IC its modeling process could take place within the workspace of the back foot.

Figures 28, 29 and 30 demonstrate the front and the back feet in isometric view in their

workspaces, separate or not.

Figure 28


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Figure 29

Figure 30


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Component Parts 3 (& 4): Development of the opposite feet

In the previous steps the development of only two of the four feet was presented. The

remaining two feet differ from the others in the direction of some slot cuts; the left feet

should have slot cuts to their right and the right feet to their left.

3.1 The existing parts needed to be copied and pasted at a new workspace in Solidworks

and at the same workspace in IronCAD.

To copy a file in SW, one must the object prior to Edit and Copy. Then, at a new workspace,

namely a new part file, he/she must select Edit and Paste.

Though IC does allow to copy the part just as SW does, it does not allow to paste it directly

into the scene. The part must be pasted into the Catalogue Browser and then dragged into

the scene. For this reason, a new tab in the catalogue browser was created. The path to do

so is displayed below.

Figure 31


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3.2 In SW, the Cut Extrusion feature corresponding to the slots was modified. The Starting

Condition was switched to Reverse Direction and Offset as in the following figure.

Figure 32

In IC, after dropping the opposite foot the H Slabs needed to be deleted and re-positioned.

Trying to position the H Slabs through geometrical constraints, namely by modifying their

reversing their distance from the axis, failed. The distance from the Axis was adjusted (Figure

33) but the H Slabs were not positioned at the desired placed, unexplainably.

Figure 33


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Thus, the right H Slabs were deleted and dropped again on the foot, this time from the left

camera/face of the part. The distances and the dimensions were re-inserted and the part

was completed.

Of course, modifying the part which stemmed from the copy-paste procedure did not

regenerate the part it came from, although it was not given a different name. This provides

evidence of lack of historic sequence in IC, which is the major characteristic of direct

modelers.

Component Part 5: Development of the first link

The feet needed two more types of rectangular parts to lash them together.

To sketch a rectangular part in SW, a rectangle needs to be sketched and extruded.

Figure 34

To create the joining slabs, a second sketch was drawn on the same plane and was extruded

by the same distance (Figure 35).


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Figure 35

Finally, two edges of the part were filleted.

Figure 36


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To develop the same part with IC, first a Slab was dropped into the scene and its dimensions

were specified.

Figure 37

Then, a second Slab was dropped on the midpoint of the first. Its dimensions were also

edited. It is notable that at first the wrong length was inputted. When it was corrected the

two midpoints of the Slabs were no longer coincident. The movement was dealt with

geometrical constraints, setting the distance of the second part from the origin to 0 (Figure

38). The issue could not be avoided even if at the beginning, prior to changing the length for

the second time, the Attach to Surface option was selected. This was attempted but

although the centerpoints remained coincident, the sides of the Slab moved (Figure 39).

Figure 38


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Figure 39

Finally, the Blend Feature was applied, similarly to the Fillet feature in SW.

Figure 40


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Component Part 6: Development of the second link

The second type of link differed from the first in its bottom face, which was equipped with a

prop for pillow.

To add material in SW, a sketch was drawn and extruded on the Bottom face of the link.

Figure 41

Then a gap was formed along the middle of the extruded area by sketching and cut

extruding a rectangle.

Figure 42


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In IC, a Slab was dragged and dropped on the dot representing the midpoint of the bottom

surface. The dimensions were inserted and the Flip Extrude Direction option was selected.

Figure 43

An H Slab was then dragged and dropped on the midpoint of the new, extruded surface. The

dimensions were inserted and the part was completed.

Figure 44


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Component Part 7: Development of the bottom back holder

To create the bottom back holder an arc, as well as two lines from the endpoints of the arc,

were sketched before being extruded as shown in Figure 45.

Figure 45

Then Fillets were added on the edges of the arc.

Figure 46


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Finally, two rectangles were sketched on the sides of the part and were extruded to create

the joining slabs.

A similar procedure was followed in IronCAD as well, since there was no Intellishapematching the one sketched in Solidworks.

A new Scene was opened, the 2D option was selected and a circle was sketched. The circles

radius was locked at 236 and from a point on the circumference of the circle a line was

sketched towards another point on the circumference. Then, the endpoints of the line were

set to be coincident to the arc and the dimension was changed to 310 mm. The arc that was

required was then distinguished. The rest of the circle was trimmed and the arc was copied

and pasted, creating a second identical arc upon the first (the result was not visible for the

moment).

Figure 47

Two vertical lines were then sketched from the endpoints of the art at dimensions equal to

the thin feature in SW. Subsequently, the arc was dragged and dropped to the opposite

endpoints of the lines, leaving its copy behind. IC set by itself the coincident constraints at

the endpoints.


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The sketch was then extruded.

Slabs were then dragged and dropped on the sides of the extruded area and the Blend

feature was applied.


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Figure 48

Then a second pair of slabs was also dragged and dropped, as there had been an omission in

the extruded sketch. No slabs were sketched as in SW.

The second pair of slabs did not need the application of the Blend feature.

Figure 49


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Component Part 8: Development of the top back holder

The Top back holder differed from the bottom one in two points; its height (extrusion depth)

and a Chamfer application.

By editing the bottom part it was easy to arrive to the top part. First the extrusion depth wasmodified (Solidworks Figure 50, IronCAD Figure 51)

Figure 50

Figure 51


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Then the Chamfer feature or shape, as referred to in IronCAD, was applied (Solidworks

Figure 52, IronCAD Figure 53).

Figure 52

Figure 53


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Component Part 9: Development of the pillow

To create a pillow with Solidworks, first a square was sketched. Then a new plane, offset

from the sketching plane, was inserted and a point was placed at where the midpoint of the

square would be, should the latter be on the new plane (Figure 54). The Loft feature was

applied to add material between the sketches and generate a curved surface.

Figure 54

Unlike Solidworks, IronCAD could not develop the curved surface through the Loft feature. A

problem message kept showing up every time the Loft was to be applied. The program

generated a cube instead (Figures 55, 56)

Figure 55


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Figure 56

After numerous configurations and attempts, the idea to apply the Loft feature was

abandoned. A Slab was inserted instead, blending its edges to rotate the

corners/intersections.

Figure 57

It turned out that IronCAD could not get along with complex curves as conveniently as

Solidworks did.


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Then, in both programs, arcs were designed on the bottom face at the corners of the part so

as to apply the Cut-Extrude feature clear some space for the feet. Figure 58 demonstrates

that it is possible to apply constraints in sketches in IC. Figure 59 depicts the same features

application in SW.

Figure 58

Figure 59

Cut-Extrude is not a separate feature in IC. There is only one Extrude feature within which

there is an option to add or remove material.


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Figure 63

Figure 64


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Figure 65


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It is evident that since the appearance of dynamic modelers a new era in CAD-CAM

emerged. History-free modeling presents a series of advantages, especially in terms of

convenience and development rapidity. The elimination of features saves a great deal of

time for CAD operators and facilitates eventual interference efforts.

On the other hand, during the contrast of IronCAD with Solidworks, in several occasions the

necessity to address to feature introduction arose. Such features are also available from

IronCAD, disclosing thus that a feature-free system is yet to be developed.

In addition, the use of constraints was also inevitable in the modeling process of our

example, a chair assembly.

IronCAD offers all the options Solidworks does, at least regarding the uses that the chairs

example required.

It turns out that a combination of the two distinct approaches is the future of CAD systems.

Although parametric and direct modeling vendors may disagree, it appears that their

conjunction era has already begun. IronCAD is an example of hybrid CAD system despite the

direct intervention probabilities.

What IronCAD and probably most direct modelers lack is the ease of use of their interface

due to the vendors poor experience. When the big CAD players decide to turn to direct

modeling characteristics the CAD technology will meet with a new historical breakthough.


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References

1. CADAZZ. CADAZZ. [Online] 2004. [Cited: May 03, 2011.] http://www.cadazz.com/cad-

software-history.htm.

2. iMB. [Online] MB Design, 2003. [Cited: May 03, 2011.]

http://mbinfo.mbdesign.net/CAD1960.htm.

3. Engineer's Handbook. [Online] 2006. [Cited: 03 May 2011.]

http://engineershandbook.com/Software/cad2.htm#3dp.

4. Wong, Kenneth. Desktop Engineering. [Online] May 28, 2009. [Cited: May 03, 2011.]

http://www.deskeng.com/articles/aaarfa.htm.

Documents

CAD (Assignment I)