Beginning AutoCAD 2002 Episode 11 pot

2 Menu bar with Draw-Block-Define Attributes and: prompt Attribute Definition dialogue box with selections for Mode, Attribute, Insertion point and Text respond with the following: 1.. 4

1 Wblocks are global and could be accessed by all AutoCAD users

2 Wblocks are usually saved to a named folder

3 Wblocks are created with the command line entry WBLOCK <R> which results in the

Write Block dialogue box

4 Wblocks are inserted into a drawing in a manner similar to ordinary blocks, the user

selecting:

a) the named folder

b) the drawing file name.

5 Wblocks can be exploded after/during insertion

6 Unexploded wblocks become blocks in the current drawing

7 All saved drawings are WBLOCKS

Assignment

A single activity for you to attempt

Activity 37: Coupling arrangement

1 Complete the drawing using your discretion for sizes not given I have deliberately not

given all sizes in this drawing

2 Insert the wblock BORDER at 5,5 – full size with no rotation

3 Insert the wblock TITLE at 412.5,7.5 and customise to suit

4 Add all text and dimensions

5 Save?

An attribute is an item of text attached to a block or a wblock and allows the user to

add repetitive type text to frequently used blocks when they are inserted into a drawing

The text could be:

a) weld symbols containing appropriate information

b) electrical components with values

c) parts lists containing coded, number off, material, etc.

Attributes used as text items are useful, but their main advantage is that attribute data

can be extracted from a drawing and stored in an attribute extraction file This data

could then be used as input to other computer packages, e.g databases, spreadsheets,

etc for creating a Bill-of-Material, an Inventory for example

This chapter is only a ‘taster’ as the topic will not be investigated fully The editing and

extraction features of attributes are beyond the scope of this book The purpose of this

chapter is to introduce the user to:

a) attaching attributes to a block

b) inserting an attribute block into a drawing.

Getting started

The attribute example for demonstration is a fisherman’s trophy and will use a previously

created and saved drawing The fish ‘symbol’ will represent the block for adding the

attributes The added attributes will give information about the type of fish, the year it

was caught and the river

1 Open the C:\BEGIN\FISH drawing created during Chapter 34 and refer to Fig 42.1

2 Erase any centre lines, text and dimensions

3 a) Move the complete shape from ‘the nose’ to the point 50,50.

b) Scale the shape about the point (50,50) by 0.5 – fig (a).

c) Note that the 50,50 point is essential for positioning the text items.

Chapter 42

Defining the attributes

Before a block containing attributes can be inserted into a drawing, the attributes must

be defined, so:

1 Make layer TEXT current

2 Menu bar with Draw-Block-Define Attributes and:

prompt Attribute Definition dialogue box

with selections for Mode, Attribute, Insertion point and Text

respond with the following:

1 At Mode:

leave all four options un-selected – no tick

2 At Attribute enter:

a) Tag: SPECIES b) Prompt: What type of fish displayed?

c) Value: ABCD

3 At Insertion point enter:

a) X: 95; Y: 60; Z: 0

4 At Text options alter:

a) Justification: scroll and pick Center b) Text Style: ST1

c) Height: 7 d) Rotation: 0 – dialogue box as Fig 42.2 then pick OK

Attributes 295

Figure 42.1 Making and using attributes with the block TROPHY.

3 The attribute tag SPECIES will be displayed in the fish symbol as Fig 42.1(b)

4 Activate the Attribute Definition command two more times and enter the followingattribute information in the Attribute Definition dialogue box in the same way as step 2

First entry Second entry

Attribute prompt Where caught? What was the year?

a) When attributes are used for the first time, the word Tag, Prompt and Value can cause

confusion The following description may help to overcome this confusion:

1 tag: is the actual attribute ‘label’ which is attached to the drawing at the

specified text start point This tag item can have any text style, heightand rotation

2 prompt: is an aid to the user when the attribute data is being entered with the

inserted block

3 value: is an artificial name/number for the attribute being entered It can have

any alpha-numeric value

b) The Insertion point in the Attribute Definition dialogue box refers to the attribute text

tag and not to a block

7 In our first attribute definition sequence, we created the SPECIES tag with the followingattribute information:

a) Tag: SPECIES.

b) Prompt: What type of fish displayed?

c) Default value: ABCD.

d) Text insertion point for SPECIES, centred on 100,55 with height 7 and 0 rotation angle.

Figure 42.2 Attribute Definition dialogue box.

Creating the attribute block

1 Menu bar with Draw-Block-Make and:

prompt Block Definition dialogue box

respond enter/activate the following:

a) Name: TROPHY b) Base point: X: 50 Y: 50 Z: 0 c) Objects: Select and window symbol and attributes as fig (d) then right-click d) Objects: Delete active

e) Preview: Create icon from Block geometry active f) Insert units: Millimeters

g) Description: TROPHY block with three attributes and dialogue box as Fig 42.3

then pick OK

2 The symbol and attributes have been made into a block and should disappear from the

screen as we activated this option from the dialogue box

Attributes 297

Figure 42.3 The Block Definition dialogue box for TROPHY.

Testing the created block with attributes

Now that the block with attributes has been created, we want to ‘test’ the attributeinformation it contains This requires the block to be inserted into the drawing, and thiswill be achieved with both command line and dialogue box entries

1 Make layer OUT current

2 At the command line enter ATTDIA <R> and:

prompt Enter new value for ATTDIA <?>

enter 0 <R>

3 ATTDIA is a system variable, and when set to 0 will only allow attribute values to beentered from the keyboard

4 At the command line enter –INSERT <R> and:

prompt Enter block nameand enter: TROPHY <R>

prompt Specify insertion pointand: pick any point to suit

prompt Enter X scaleand enter: 1 <R>

prompt Enter Y scaleand enter: 1 <R>

prompt Specify rotation angleand enter: 0 <R>

prompt What type of fish displayed?<ABCD>and enter: COD<R>

prompt Where caught?<WXYZ>and enter: CLYDE <R>

prompt What was the year?<9999>and enter: 1984 <R>

4 The fish trophy symbol will be displayed with the attribute information as fig (e)

5 Note

a) the prompt and defaults values are displayed as entered

b) the order of the last three prompt lines (i.e type, caught and year) may not be in the

same order as mine Don’t worry if they are not the same

6 Now insert the trophy block twice more with –INSERT from the command line using:

a) at any suitable point, full size with 0 rotation and accept the default values, i.e

right-click or <R> at the prompt line – fig (f)

b) at another point on the screen with the X scale factor as 0.75, the Y scale factor as

1.25, the rotation angle –5 Use the same attribute entries as step 4, i.e COD, CLYDEand 1984 The result should be as fig (g)

7 Explode any inserted block which contains attribute information and the tags will bedisplayed – fig (h)

8 We are now ready to insert the ‘real’ attribute data

Attribute information

The fisherman’s trophy cabinet contains five prime examples of what he has caught overthe past few years, and each catch is represented in the trophy cabinet by the blocksymbol containing the appropriate attribute information The attribute data to bedisplayed is:

Attribute information can be added to an inserted block:

a) from the keyboard – as previous example

b) via a dialogue box which will now be discussed.

1 Erase all objects from the screen and make layer OUT current

2 At the command line enter ATTDIA <R> and:

prompt Enter new value for ATTDIA<0>

enter 1 <R>

3 Menu bar with Insert-Block and:

prompt Insert dialogue box

with Block name: TROPHY – from previous insertion

respond 1 ensure all on-screen prompts not active, i.e no tick

2 insertion point:- X: 40; Y: 230; Z: 0

3 scale: X: 1.2; Y: 1.2; Z: 1

4 rotation: angle 0

5 pick OK

prompt Edit Attributes dialogue box

with Entered prompts and default valuesas Fig 42.4(a)

respond 1 alter What type to: SALMON

2 alter Where caught to: SPEY

3 alter What year to: 1995

4 dialogue box as Fig 42.4(b)

5 pick OK

4 The trophy block will be inserted with the attribute information displayed

5 Using step 3 as a guide with the attribute data listed above, refer to Fig 42.5 and insert

the TROPHY block to complete the cabinet – use your imagination with the scales

6 Complete the cabinet and save?

This completes our brief ‘taster’ into attributes

Attributes 299

Figure 42.4 The Edit Attributes dialogue box.

Point of interest?

In the previous chapter we created a title box as a wblock This title box had text itemsattached to it, e.g drawing name, date, revision, etc These text items could have beenmade as attributes When the title box was inserted into a drawing, the various text items(attributes) could have been entered to the drawing requirements Think about thisapplication of attributes!

Summary

1 Attributes are text items added to BLOCKS or WBLOCKS

2 Attribute must be defined by the user

3 Attribute data is added to a block when it is inserted into a drawing

4 Attributes can be edited and extracted from a drawing, but these topics are beyond thescope of this book

Figure 42.5 The fisherman’s cabinet using block TROPHY.

External references

Wblocks contain information about objects, colour, layers, linetypes, dimension styles,

etc and all this information is inserted into the drawing with the wblock All this

information may not be required by the user, and it also takes time and uses memory

space Wblocks have another disadvantage, this being that drawings which contain

several wblocks are not automatically updated if one of the original wblocks is altered

External references (or xrefs) are similar to wblocks in that they are created by the user

and can be inserted into a drawing, but they have one major advantage over the wblock

Drawings which contain external references are automatically updated if the original

external reference ‘wblock’ is modified

A worked example will be used to demonstrate external references The procedure may

seem rather involved as it requires the user to save and open several drawings, but the

final result is well worth the effort For the demonstration we will:

a) create a wblock

b) use the wblock as an xref to create two drawing layouts

c) modify the original wblock

d) view the two drawing layouts.

e) use the existing C:\BEGIN folder

Getting started

1 Open your A3PAPER standard drawing sheet and refer to Fig 43.1

2 Make a new current layer with:

name: XREF; colour: red; linetype: continuous

3 Draw:

a) a circle of radius 18

b) a item of text, middled on the circle centre with height 5 and rotation angle 0 The

item of text is to be AutoCAD and is to be colour blue – fig (a)

Creating the xref (a wblock)

1 At the command line enter WBLOCK <R> and:

prompt Write Block dialogue box

respond 1 Source: Objects

2 Base point: Pick point and pick circle centre point

3 Objects: Select objects, pick circle and text then right-click

4 Objects: Delete from drawing active

5 File name: XREFEX

6 Location: C:\BEGIN

7 Insert units: Millimeters

8 pick OK

2 A preview of the wblock will be displayed and a blank screen returned, due to the delete

from drawing option being active

Chapter 43

Inserting the xref (drawing layout 1)

1 Menu bar with File-Close (no to save changes) then menu bar with File-Open and

select your A3PAPER standard sheet again with layer OUT current

2 Menu bar with Insert-External Reference and:

prompt Select Reference File dialogue box(looks familiar?)

respond 1 scroll and pick C:\BEGIN

2 scroll and pick XREFEX

3 pick Open

prompt External Reference dialogue box

with Name: XREFEX and Path: C:\BEGIN\XREFEX.dwg

respond 1 ensure Reference Type: Attachment (black dot)

2 Retain path active

3 all on-screen options active, i.e tick

4 dialogue box similar to Fig 43.2

5 pick OK

prompt Attach Xref “XREFEX”: C:\BEGIN\XREFEX.dwg

then Specify insertion pointand enter: 50,50 <R>

prompt Enter X scaleand enter: 1 <R>

prompt Enter Y scaleand enter: 1 <R>

prompt Specify rotation angleand enter: 0 <R>

3 The named external reference (XREFEX) will be displayed at the insertion point entered.The complete process seems similar to inserting a wblock?

Figure 43.1 External reference example.

4 Now rectangular array the inserted attached xref for:

a) 5 rows with row offset: 50

b) 6 columns with column offset: 60.

5 Save the layout as C:\BEGIN\XREFLAY1 – Fig 43.1(c).

Inserting the xref (drawing layout 2)

1 Close the existing drawing then re-open A3PAPER

2 At the command line enter XREF <R> and:

prompt Xref Manager dialogue box

respond pick Attach

prompt Select Reference File dialogue box

respond 1 scroll and pick XREFEX from your C:\BEGIN folder

2 pick OK

prompt External Reference dialogue box

respond 1 Reference Type: Attachment

2 De-activate the three on-screen prompts (no tick)

d) rotate items as copied active

4 Save the layout as C:\BEGIN\XREFLAY2 – Fig 43.1(d).

External references 303

Figure 43.2 The External Reference dialogue box.

Modifying the original xref

1 Close the current drawing

2 Open the original XREFEX drawing from C:\BEGIN This is the original wblock

3 a) Change the text item to R2002 and colour green

b) Draw a hexagon, centred on the circle and circumscribed in a circle of radius 19.

Change the colour of this hexagon to blue These modifications are shown in Fig 43.1(b)

4 Menu bar with File-Save to automatically update C:\BEGIN\XREFEX.

Viewing the original layouts

1 Close the existing drawing

2 Menu bar with File-Open and:

b) note the Preview then pick Open

c) again an interesting result?

4 The layout drawings should display the modified XREFEX without any ‘help’ from us.This is the power of external references Surely this is a very useful (and dangerousconcept)?

5 Menu bar with Format-Layer and note the layer: XREFEX|XREF This indicates that

an external reference (xrefex) has been attached to layer xref The (|) is a pipe symbolindicating an attached external reference

6 This completes our simple investigation into xrefs

Summary

1 External references are wblocks which can be attached to drawings

2 When the original xref wblock is altered, all drawing files which have the externalreference attached are automatically updated to include the modifications to the originalwblock

Isometric drawings

An isometric is a 2D representation of a 3D drawing and is useful as it can convey

additional information about a component which is not always apparent with the

traditional orthographic views Although an isometric appears as a 3D drawing, the user

should never forget that it is a ‘flat 2D’ drawing without any ‘depth’

Isometric drawings are created by the user with polar coordinates and AutoCAD has the

facility to display an isometric grid as a drawing aid

Setting the isometric grid

There are two methods for setting the isometric grid these being by using a dialogue box

and via the keyboard

Dialogue box method

1 From the menu bar select Tools-Drafting Settings and:

prompt Drafting Settings dialogue box

respond pick the Snap and Grid tab and:

1 Snap On(F9) active – black dot

2 Grid On(F7) active

3 Snap type & Style with:

a) Grid snap active b) Isometric snap active

4 set Grid Y Spacing: 10

5 set Snap Y Spacing: 5

6 dialogue box as Fig 44.1

7 pick OK

Chapter 44

Figure 44.1 The Drafting Settings dialogue box.

2 The screen will display an isometric grid of 10 spacing, with the on-screen cursor ‘aligned’

to this grid with a snap of 5

3 Use the Drafting Settings dialogue box to ‘turn the isometric grid off’, i.e pick theRectangular snap

4 The screen will display the standard grid pattern

Keyboard entry method

1 At the command line enter SNAP <R> and:

prompt Specify snap spacing or [ON/OFF/Aspect/Rotate/Style/Type]

enter S <R> – the style option

prompt Enter snap grid style [Standard/Isometric]

enter I <R> – the isometric option

prompt Specify vertical spacing<5.00>

1 AutoCAD uses three ‘planes’ called isoplanes when creating an isometric drawing, these

being named top, right and left The three planes are designated by two of the X, Y and

Z axes as shown in Fig 44.2(a) and are:

a) isoplane top: XY axes

b) isoplane right: XZ axes

c) isoplane left: YZ axes

2 When an isoplane is ‘set’ or ‘current’, the on-screen cursor is aligned to that isoplaneaxis – Fig 44.2(b)

3 The isoplane can be set by one of three methods:

a) at the command line enter ISOPLANE <R> and:

prompt Enter isometric plane setting[Left/Top/Right]

enter R <R> – right plane

b) Using a ‘toggle’ effect by:

1 holding down the Ctrl key (control)

2 pressing the E key

3 toggles to isoplane left

4 Ctrl E again – toggles to isoplane top

c) Using the F5 function key:

1 press F5 – toggles isoplane right

2 press F5 – toggles isoplane left, etc

4 Note:

It is the users preference as to what method is used to set the isometric grid and isoplane,but my recommendation is:

a) set the isometric grid ON from the Drafting Settings dialogue box with a grid spacing

of 10 and a snap spacing of 5

b) toggle to the required isoplane with Ctrl E or F5

c) isoplanes are necessary when creating ‘circles’ in an isometric ‘view’.

Isometric circles

Circles in isometric are often called isocircles and are created using the ellipse command

and the correct isoplane MUST be set Try the following exercise:

1 Set the isometric grid on with spacing of 10 and toggle to isoplane top

2 Using the isometric grid as a guide and with the snap on, draw a cuboid shape as Fig

44.2(c) The size of the shape is not important at this stage – only the basic shape

3 Select the ELLIPSE icon from the Draw toolbar and:

prompt Specify axis endpoint or [Arc/Center/Isocircle]

enter I <R> – the isocircle option

prompt Specify center of isocircle

respond pick any point on top ‘surface’

prompt Specify radius of isocircle

respond drag and pick as required.

4 Toggle to isoplane right with Ctrl E

5 At the command line enter ELLIPSE <R> and:

prompt Specify axis endpoint or [Arc/Center/Isocircle]

enter I <R>

prompt Specify center of isocircleand pick a point on ‘right side’

prompt Specify radius of isocircleand drag/pick to suit

6 Toggle to isoplane left, and draw an isocircle on the left side of the cuboid

7 The cuboid now has an isometric circle on the three ‘sides’

8 Now continue with the example which follows

Isometric example

1 Open your A3PAPER standard sheet and refer to Fig 44.3

2 Set the isometric grid on, with a grid spacing of 10 and a snap spacing of 5

3 With the LINE icon draw:

First point: pick towards lower centre of the screen

Next point and enter: @80<30 <R>

Next point and enter: @100<150 <R>

Next point and enter: @80<–150 <R>

Next point and enter: @100<–30 <R>

Next point and enter: @50<90 <R>

Next point and enter: @80<30 <R>

Next point and enter: @50<–90 <R><R> – fig (a)

Isometric drawings 307

Figure 44.2 Three isometric concepts.