The aim of this tutorial is to edit block and external references. After studying this tutorial, you should be able to:

• edit a block reference, and
• edit an external reference.

Here, blocks and external references are considered as references. By using in-place reference editing technique, you can edit a block within a drawing without having to explode a block definition and to redefine the block, and you can edit an externally referenced drawing without having to open the external drawing.

Start a new drawing from scratch. Use Metric defaults. Then use the BOX command to construct a solid box. After that, set the display to an isometric view. See Figure 1.

<File> <New...>

Command: NEW
[Create New Drawing
Start from Scratch
Metric
OK ]

<Draw> <Solids> <Box>

Command: BOX
Specify corner of box or [CEnter]: 10,10
Specify corner or [Cube/Length]: @40,30,20

<View> <3D Views> <SW Isometric>

Use the BASE command to set the insertion base point. Then save and close the drawing.

<Draw> <Block> <Base>

Command: BASE
Enter base point: [Select A (Figure 1).]

<File> <Save>
File name: Refed01.dwg

<File> <Close>
Command: CLOSE

Now sStart another new drawing. Then turn on the AutoCAD Design Center. After that, select the Desktop button and the directory in which you save the last drawing. See Figure 2.

<File> <New...>

Command: NEW
[Create New Drawing
Start from Scratch
Metric
OK ]

<Tools> <AutoCAD DesignCenter>
Command: ADCENTER

Figure 2 AutoCAD Design Center and drawing selected

Select the drawing in the Palette of the AutoCAD Design Center. Then select the right mouse button (Figure 3). After that, select the Insert as Block... item to insert the drawing as a block. See Figure 4.

Figure 4 Insert dialog box

In the Insert dialog box, select the OK button and select a point on the screen. Then use the INSERT command to insert the block again. After that, set the display to an isometric view. See Figure 5.

Specify insertion point or [Scale/X/Y/Z/Rotate/PScale/PX/PY/PZ/PRotate]: 20,20

<Insert> <Block...>

Command: INSERT
Specify insertion point or [Scale/X/Y/Z/Rotate/PScale/PX/PY/PZ/PRotate]: 100,40

<View> <3D Views> <SW Isometric>

Figure 5 Blocks inserted and display set

Construct a solid cone. See Figure 6.

<Draw> <Solids> <Cone>

Command: CONE
Specify center point for base of cone or [Elliptical]>: MID of [Select A (Figure 5).]
Specify radius for base of cone or [Diameter]: 10
Specify height of cone or [Apex]: 30

Figure 6 Solid cone constructed

Use the REFEDIT command to edit one of the block insertion. Figure 7.

<Modify> <In-place Xref and Block Edit> <Edit Reference>

Command: REFEDIT
Select reference: [Select A (Figure 6).]

Figure 7 Reference Edit dialog box

Select the [OK] button. Then select the block.
Select nested objects: [Select A (Figure 6).]
Use REFCLOSE or the Refedit toolbar to end reference editing session.

Now use the SUBTRACT command to subtract the cone from the select block. See Figure 8.

<Modify> <Solids Editing> <Subtract>

Command: SUBTRACT
Select solids and regions to subtract from ..
Select objects: [Select A (Figure 7).]
Select objects: [Enter]
Select solids and regions to subtract ..
Select objects: [Select B (Figure 7).]
Select objects: [Enter]

Figure 8 Block modified

To save the change, use the REFCLOSE command by selecting the Save back changes to reference button of the Refedit toolbar. See Figure 9.

Command: REFCLOSE

Figure 9 Block definition modified

Note in Figure 9 that the other block is also changed because the block definition is modified.

External Reference Editing

Start another new drawing. Then select the drawing Refed01 from the palette of the AutoCAD Design Center. After that, select the right mouse button and the Attach as Xref... button. See Figure 10.

<File> <New...>

Command: NEW
[Create New Drawing
Start from Scratch
Metric
OK ]

Figure 10 AutoCAD Design Center

Specify the insertion point. Then set the display to an isometric view. See Figure 11.

Specify insertion point or [Scale/X/Y/Z/Rotate/PScale/PX/PY/PZ/PRotate]: 10,10

<View> <3D Views> <SW Isometric>

Figure 11 Drawing attached and display set

Construct a solid cylinder. See Figure 12.

<Draw> <Solids> <Cylinder>

Command: CYLINDER
Specify center point for base of cylinder or [Elliptical]: MID of [Select A (Figure 11).]
Specify radius for base of cylinder or [Diameter]: 10
Specify height of cylinder or [Center of other end]: 30

Figure 12 Solid cylinder constructed

Use the REFEDIT command. Then use the SUBTRACT command to modify the external reference. After that, use the REFCLOSE command. See Figure 13.

<Modify> <In-place Xref and Block Edit> <Edit Reference>

Command: REFEDIT
Select reference: [Select A (Figure 12).]
[Reference Edit
OK ]
Select nested objects: [Select A (Figure 12).]

<Modify> <Solids Editing> <Subtract>

Command: SUBTRACT
Select solids and regions to subtract from ..
Select objects: [Select A (Figure 12).]
Select objects: [Enter]
Select solids and regions to subtract ..
Select objects: [Select B (Figure 12).]
Select objects: [Enter]

<Modify> <In-place Xref and Block Edit> <Save Reference Edits>

Command: REFCLOSE
[AutoCAD
All references edits will be saved
OK ]

Figure 13 External referenced drawing modified

Save and close the drawing.

Now open the drawing Refed01.dwg. Note that it is modified.

You can edit the block and the externally referenced drawing by using the REFEDIT command. This command enables you to edit a block in a drawing and to edit an external referenced drawing.