1. ENGT 122 – CAD I Chapter 14 - Blocks

2. What’s a Block?  Block - A group of objects combined to create a single object.  Can be named and saved for later retrieval (BLOCK).  Can be repeatedly inserted into a drawing at any time (INSERT).  Comprised of any number of objects, but treated as a single object that can be easily moved, rotated, scaled, and copied.

3. What’s a Block?  Individual objects comprising a block can be “recovered” using the EXPLODE command.  An inserted Block is referred to as a “Block Reference”.  Once created, a block can be modified (redefined), and all inserted block references will update accordingly.  Blocks can be “nested” within another block.

4. Some Advantages of Blocks  Allows a previously created drawing or portion of a drawing to be reused in the same drawing or another drawing without recreating it.  Allows extensive libraries of symbols and parts to be created, stored, and accessed at any time.  Reduces drawing time.  Assures standardized symbol conventions and part dimensions within the organization.

5. Some Advantages of Blocks  Greatly simplifies drawing changes.  Example: an assembly has 150 similar bolts. If the bolt specification changes, the block definition can be easily edited and the assembly will update to reflect the change on all bolts.  Greatly reduces drawing file size. The objects comprising a block are only stored once, during definition of the block. Each block insertion is merely a reference to the original block definition (ex: 500 block insertions of a bolt require little more storage requirements than a single bolt).

6. Block Example:  Standardized electrical symbol library can be created from Block entities and later used to create circuit diagrams.

7. DEMO 1:  Load file Demo1.dwg.  Show example of electrical symbol Block insertion

8. Learning Objectives  Create blocks with the BLOCK command.  Insert blocks with the INSERT command.  Split a block into individual objects using the EXPLODE command.  Learn to redefine a block.  Create drawing files using the WBLOCK command.  Redefine the insertion base point for a drawing.  Rename blocks and purge unused blocks.

9. Creating Blocks  Step 1: Create the objects to be grouped in the block using AutoCAD drawing commands, but note;  When inserted, each entity in the block will retain the properties of the layer it was created in or inherit the properties of the current layer according to table below: If you want objects in a block to: Create objects on these layers Create objects with these properties Retain original properties and layer when inserted Any but 0 (zero) Any but BYBLOCK Inherit properties and layer from the layer current during insert 0 (zero) BYLAYER Retain original layer but inherit specific individual properties according to current property settings Layer you want inserted block to be placed on BYBLOCK

10. Creating Blocks  Step 2: Make sure the objects to be placed in the block are visible. Then, issue the Make Block Command using command line, drop down menu, or toolbar. Command: BLOCK Command: BLOCK All methods bring up Block Definition dialog box. Draw Toolbar

11. Block Definition Dialog Box

12. DEMO 2:  Open file Demo2.dwg.  Create some geometry.  Demonstrate Make Block Commands and Block Definition dialog box;  BLOCK

13. Exercise 1:  Start a new drawing using an English template.  Set the current layer to Layer 0 and then create the simplified bolt shown (without dimensions). When inserted, this block will inherit the properties of whichever layer is current.  Using the bolt geometry, create a block named BOLT.  The base point should be at the location indicated.  Use the Delete option for the selected objects.  Save your file as Ex1.dwg. You will need it later. Base Point at midpoint

14. Inserting Blocks  Step 3 – Once created, the block is stored locally in the current drawing file.  To insert a copy of the block, the INSERT command can be used.  Set the current layer and/or adjust settings in the Properties toolbar before using INSERT;  Each block object will be placed on the current layer.  All block objects created on “Layer 0” will inherit properties from the current layer.  All block objects created with Properties set to BYBLOCK will inherit specific individual properties according to current property settings.

15. Inserting Blocks  A Block is inserted using the INSERT command; Command: INSERT Command: INSERT  Insert dialog box appears Draw Toolbar: Insert Block

16. Inserting Blocks  Insert dialog box allows;  A predefined block to be inserted, or  A drawing file to be inserted as a block.

17. DEMO 3:  Show the INSERT command using block made in Demo 2. Illustrate inserting;  A predefined block  An external file Demo3.dwg (title block) as a block.

18. Exercise 2A:  Use the same drawing file from Exercise 1 (Ex1.dwg) and create the geometry shown using a new layer called JOINT with color = Magenta (no dimensions).  Then create a new layer called BOLTBLOCK using color = Green, linetype = continuous, linewight = 0.7.  Set the current layer to Layer BOLTBLOCK.

19. Exercise 2B:  Use the INSERT command to insert 3 copies of your block named BOLT as shown below.  Notice the blocks inherit the properties of the current layer (BOLTBLOCK ). Why?  Save your file as Ex2.dwg. You will need this later.

20. Editing Block Definitions  A bock is treated as a single object, but is comprised of multiple objects.  To make a change in a block, it must first be “Exploded” to divide it into its components.  Use the INSERT command with the Explode option to insert the block in an exploded state, or…  Or use the EXPLODE command on a previously inserted block. Command: EXPLODE DDMenu: Modify > Explode Modify Toolbar: Explode

21. Editing Block Definitions  Once in the exploded state, the individual objects comprising the block can be edited and modified.  After making the required changes, the block can be “Redefined” as follows;  Reissue the BLOCK command.  Reselect the objects comprising the block.  Provide the original block name  AutoCAD will issue a warning, “Block is already defined, Do you want to redefine it?”  Select “YES”.  The block is now redefined and incorporates the changes you made. All blocks inserted previously with this name will update accordingly! Wowee!

22. DEMO 4:  Open Demo4.dwg.  Insert an exploded version of diode.  Redefine diode and view update.  Insert a non-exploded version of resistor.  Use EXPLODE to explode resistor.  Redefine resistor and view update.

23. Exercise 3A:  If not currently open, reopen drawing Ex2.dwg which you saved in the previous exercise.  Away from the existing objects, insert a copy of your block named BOLT using the Explode option.  Use STRETCH to increase the length of the exploded bolt by 2”.  Then Set the current layer to layer 0 and add some simple threads using COPY or ARRAY. Exploded Bolt block

24. Exercise 3B:  Use the modified bolt geometry to redefine your block called BOLT. Use the Retain option for selected objects, and use the same base point as previously.  Respond YES to the message Bolt already defined, do you want to redefine it?  Your bolts should all update by increasing in length. Base Point at midpoint

25. End Lesson 30

26. Block Layers Review of Layers as pertaining to blocks: If you want objects in a block to: Create objects on these layers Create objects with these properties Retain original properties and layer when inserted Any but 0 (zero) Any but BYBLOCK Inherit properties and layer from the layer current during insert 0 (zero) BYLAYER Retain original layer but inherit specific individual properties according to current property settings Layer you want inserted block to be placed on BYBLOCK

27. DEMO 5:  Open file Demo5.dwg.  Show how object creation layer affects block insert properties and layer.

28. Nested Blocks  Nested Block  If the BLOCK command is issued to create a block, and another block is selected as one of the objects, a nested block is formed (one within another).  The depth of nesting is unlimited.

29. DEMO 6:  Load Demo6.dwg.  Show Nested block.  Create a small circuit using existing blocks.  Convert circuit into a larger block with nesting.

30. WBLOCKS  Blocks are stored locally in the drawing file they were created in and are not directly accessible in other drawings.  The WBLOCK command (called Write Block) overcomes this deficiency.  Any drawing file can be inserted as a block.  WBLOCK  glorified save command that creates a drawing file from a portion of your current file.  selected objects  predefined block  or the entire drawing  These new drawing files can then be inserted as blocks in any other drawing file.

31. WBLOCKS To Create a WBLOCK:  Command: WBLOCK  Displays Write Block dialog box.

32. DEMO 7:  Load file Demo7.dwg.  Show the WBLOCK command using;  A predefined block  Entire drawing  Selected objects  Show WBLOCK insert.

33. Exercise 4A:  Open a new drawing.  Create a layer called BLOCKS (any color & line type).  Make layer BLOCKS current, then set the Properties Control for color, linetype, and lineweight to BYBLOCK.  Create the objects shown below without dimensions.

34. Exercise 4B:  Create a Wblock named SmallBolt using the geometry and base point indicated. Save it where you can find it!  Create a Wblock named BigBolt using the geometry and base point indicated. Save it where you can find it!  Create a Wblock named nut using the geometry and base point indicated. Save it where you can find it!  Save your file. Base Point at midpoint Wblock named SmallBolt WBlock named BigBolt WBlock named Nut Base Point Base Point at midpoint

35. Exercise 4C:  Open a new drawing file and create the geometry shown below (without dimensions).  Create a new layer called BOLT (any color & line type).  Make BOLT the current layer.

36. Exercise 4D:  Set your Properties Controls as shown below. Use INSERT to Insert block SmallBolt shown in green  Adjust Property controls as shown below and Use INSERT to Insert block Bigbolt shown in yellow.  Adjust Property controls as shown below and Use INSERT to Insert two blocks nut shown in red.

37. Defining Base Points  When a drawing file (i.e. WBLOCK created by Entire Drawing option) is used for block insertion, the base point defaults to the drawing origin.  If the file is frequently used as a block, it’s desirable to reset the base point to a specific location.  BASE command accomplishes this.  Open the drawing file to be used as a block.  Issue the BASE command; Command: BASE DDMenu: Draw > Block > Base  Select a new base point and resave the file.

38. DEMO 8:  Open file Demo8A.dwg and show contents. Then close it.  Open file Demo8B.dwg and Insert Demo8A.dwg as a block with original BASE.  Edit the BASE in Demo8A.dwg using the BASE command, then save it.  Insert Demo8A.dwg as a block with new BASE.

39. Editing WBlock Definitions  Redefining an externally referenced block (one from another file) will update the block locally but not in the source file.  WBLOCKS and Drawing files used as blocks should be edited directly in the source file and re-saved.

40. Renaming Blocks  A block can be renamed using the RENAME command: Command: RENAME DDMenu: Format > Rename…  Rename dialog box displays.  Select the name to change.  Enter a new name and pick the Rename To button.  Select OK.  Rename can be used for other entities too.

41. DEMO 9:  Open Demo9.dwg.  Rename some of the blocks.  RENAME can be used for other entities.

42. Deleting Unused Blocks  To remove unused blocks from the drawing use the PURGE command. DDMenu: File > Drawing Utilities > Purge… Command: PURGE  Purge dialog box displays.  Expand the tree labeled Blocks. Only unused blocks will be visible.  “Non-purgable” items can be viewed by selecting view items you cannot purge.  Nested blocks can be purged by selecting Purge nested items. PURGE can be used for other entities too!

43. DEMO 10:  Open Demo10.dwg.  Delete all blocks then insert a couple blocks.  Show the PURGE command.  PURGE can be used for other entities.

44. Exercise 5:  Create the objects shown. Then generate a block for each using the name indicated and the Delete option.  Insert a copy of each block.  Rename the blocks as follows: CIRCLE  ROUND; RECTANGLE  BOX; HEX  POLYGON  Try to PURGE the blocks.  Delete the inserted blocks, then try PURGE again. Block: CIRCLE Block: RECTANGLE Block: HEX

45. End Lesson 31

46. End Lesson 32

47. The End

48. RETIRED MATERIAL

49. Creating Blocks  Step 1: Create the objects to be grouped in the block using AutoCAD drawing commands, but note;  When inserted, each entity in the block will retain the properties of the layer it was created in or inherit the properties of the current layer according to table below: If you want objects in a block to: Create objects on these layers Create objects with these properties Retain original properties and layer when inserted Any but 0 (zero) Any but BYBLOCK Inherit properties and layer from the layer current during insert 0 (zero) BYLAYER Retain original layer but inherit specific individual properties according to current property settings Layer you want inserted block to be placed on BYBLOCK

50. Inserting Blocks Affect of Scale Factor:  Block can be mirrored during insertion by using a negative scale factor.  If X-Scale negative  mirrors about Y-axis.  If Y-Scale negative  mirrors about X-axis. Basepoint

51. Nested Blocks  Nested Block  If the BLOCK command is issued to create a block, and another block is selected as one of the objects, a nested block is formed (one within another).  The depth of nesting is unlimited.  Special rules for how layers, colors, and linetypes are affected in a nested block:  If an inner block has objects on Layer 0, or objects with linetype or color specified BYBLOCK, the objects acquire the properties of the first fixed layer encountered in a higher level nest.  If no fixed layers are found, the Layer 0 and BYBLOCK objects acquire color = white, linetype = continuous, line weight = default.