When you have completed this Module you will be able to:
1. Explain sectional views, sections, and hatching in sectional views.2. Describe and apply the BHATCH, HATCHEDIT, and SNAPBASE commands to insert
and edit hatching patterns.
Drafting LessonCross Sections - Part 1
When a view of an objectrequires a clearerdescription of the interiorof the object or it is hardto dimension because ofthe hidden lines, a crosssection view can bedrawn in place of thenormal multiview.
Normal Front and RightSide View of an Object
Sometimes an additionalview is drawn.
3D Model of the ObjectShowing the Cutting Plane Line
A cross section view,also called a section,is a view of the objectas if it were cut alonga cutting plane andthe two pieces pulledapart exposing theinside of the object. Acutting plane line isthe line along theobject where the cutwould have beenmade. The arrows
3D Model of the ObjectShowing it Cut on the
Cutting Plane Line
A Front view and RightSide Section View
point in the direction that you are looking when youdraw the view. The surfaces of the object that aresolid when cut, are crosshatched.
Crosshatching in AutoCADIn many drafting and design areas there are applications that require you to fill an area with apattern. This is called crosshatching or just hatching. Hatching patterns are used to show anobject's material type, the solid material that was cut through in the sectional view, a differencefrom one area to another plus many other applications. In this module, you will learn how toinsert and edit hatching patterns.
Hatching BoundariesThe BHATCH command is used to insert hatching. It allows you two different methods ofselecting the boundary of the area to be filled in with the hatch. The first method is to pick aninternal point and allow the BHATCH command to find an enclosed boundary. This methodworks well most of the time but for more complicated drawings, the second method must beused. The second method involves using an existing closed polyline as the hatching area. Youmust create the closed polyline first using the PLINE, PEDIT or BOUNDARY commands. Sincea circle or an ellipse is a closed object, they can also be used as a closed polyline.
Hatching PatternsThere are many predefined hatch patterns including industry standard, ISO standard and asolid fill pattern that are part of AutoCAD's software. You can also find additional patterns onthe internet, in online magazines or you can define your own simple patterns on the fly. In theAutoCAD Customization Modules, you will learn how to define your own custom hatchingpatterns. All hatch patterns are constructed using lines but the hatch pattern is inserted as asingle object in the drawing. This helps you to manipulate the hatch object and also keeps thedrawing database smaller. A hatching pattern can be exploded using the EXPLODE commandback into its individual line objects.
AutoCAD Command: BHATCHThe BHATCH command is used to insert hatch patterns.
Shortcut: BH
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2000-2002
A hatch object is constructed using lines but acts as a single AutoCADobject in the drawing. This helps you to manipulate the hatch object andalso keeps the drawing database smaller. A hatch can be exploded intoindividual line objects with the EXPLODE command but associativity will belost if it is exploded.
Using the BHATCH CommandStep 1 Start a new drawing using the template Module Template B.
Step 2 Save and name the drawing AutoCAD 2D Workalong 29-1.Step 3 Enter theBHATCH command. Itwill open the Hatchdialogue box. TheHatch dialogue box hasa slightly different look in2006 to 2008 then itdoes in 2000 to 2005.See Figure Step 3A and3B. The More or Lessicon shown below andlocated in the bottomright corner of the box in2006 to 2008 is used toopen or close theadvanced portion of thedialogue box.
Figure Step 3A - AutoCAD 2006 - 2008
In AutoCAD 2000 to 2005, the Quick and Advanced tabs are used to do the same thing.See Figure Step 3B.
Step 4 Create layers Object, Hatch and Construction as shown in Figure Step 4.
Step 5 Open drawingAutoCAD 2D Workalong28-1 that you completed inModule 28. See FigureStep 5.
Figure Step 4
Figure Step 5
Step 6 Using the COPYCLIPcommand, copy the bottomobject into the drawingAutoCAD 2D Workalong 29-1.Copy it four times located asshown in Figure Step 6. Lineup the copies and center themusing what you have learnedto this point in the course.Their exact location is notimportant for this exercise butensure they are lined up witheach other.
Step 7 Using theDTEXT command,add the text in eachcopy as shown inFigure Step 7. Usefont Romans at aheight of 0.25.
Step 8 Set the current layer to Hatch. Enter theBHATCH command and in Hatch dialogue boxset the Type and pattern to ANSI31 as shown in FigureStep 8.
Figure Step 8
29 - 5
Figure Step 9
Step 9 Ensure that in the Angle and scale box, theAngle is set to 0 and the Scale is set to 1. SeeFigure Step 9.
Step 10 In the Options box, ensure that Associative is enabledas shown in Figure Step 10.
Authors Comments:Figure Step 10
The area to be hatched can be hatched using either the Pick Point method or the SelectObject method. They will produce very different results and are used for different purposesas you will see as you work your way through this module.
Step 11 In the Boundaries box, click the Add Pick points icon andthen pick the point P1 in Part A as shown in Figure Step 11B. Noticein the Figure Step 11C, the hatch pattern will hatch the ellipse withouthatching over the text.
Figure Step 11B
Figure Step 11A
Figure Step 11C
Step 12 Click OK to complete the command. See Figure Step 12.
Step 13 Enter the BHATCH command again. Inthe Hatch dialogue box, set the Pattern to ANSI31,the Angle to 45 degrees and the Scale to 0.5 asshown in Figure Step 13.
Step 14 Click the Add Select objects icon asshown in Figure Step 14A and the select the ellipsein Part B as shown in Figure Step 14B. Note inFigure Step 14C how the hatching pattern will ignoreeverything inside theobject. In this example,the text object is ignoredand the hatching goes Figure Step 14Athrough it.
Figure Step 14B
Figure Step 13
Figure Step 14C
Figure Step 15B
...continued on page 29-7
Step 15 Enter the BHATCH command.To pick the pattern this time, click the ...icon, see Figure Step 15A, at the end ofthe Pattern box to open the Hatch PatternPalette dialogue box. See Figure Step15B. Select the AR-HBONE pattern.
Step 19 On layer Object, draw a 1inch diameter circle in the center of theellipse in Part C and Part D. SeeFigure Step 19.
Figure Step 19
Figure Step 20A
Step 20 Enter the BHATCH command and ensurethe Islands box is set to Normal as shown in FigureStep 20A. Set the Types and pattern to Stars, theAngle to 0 and Scale to 0.5 as shown in Figure Step20B....continued on page 29-8
Step 21 Click the Add Pick points icon and then inPart C, select point P4 as shown in Figure Step 21A.Part C should now appear as shown in Figure Step21B. Note how when the Islands display style is setto Normal, the hatching patterns will hatch every otherisland.
Figure Step 21B
Step 22 Enter the BHATCH command and set theIslands display style to Outer as shown in FigureStep 22.
Step 23 Click the Add Pick points icon and inPart D select point P5 as shown in Figure Step23A. Part D should now appear as shown inFigure Step 23B. Note how only the outerboundary is hatched. Your drawing shouldappear as shown in Figure Step 23C.
An associative hatch will automatically adjust when the boundary that was used when it wascreated is moved or changed. A nonassociative hatch remains the same size and in the samelocation regardless of the changes made to the hatch boundary. An associative hatch is thedefault in the BHATCH command.An associative hatch can be changed to a nonassociative hatch by changing the properties ofthe object with the Properties window or with the HATCHEDIT command. A nonassociativehatch can never be changed to a associative hatch. It would have to be deleted and reinsertedas associative.
AutoCAD Command: HATCHEDITThe HATCHEDIT command is used to edit existing associative hatches.
Shortcut: none
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2000-2002
AutoCAD System Variable: SNAPBASEThe SNAPBASE system variable is used to change the origin point for hatching patterns. It alsochanges the start point for the grid and snap points.
Shortcut: none
The FILL command controls the fill of a hatching pattern. If toggled off,hatch patterns will not appear on the drawing. This can help you work fasteras your drawing willregenerate faster. Do notforget to turn the FILL on
when finished. You must execute theREGEN command to display the currentfillmode after you use the FILL command. FILL - ON FILL -OFF
Using the HATCHEDIT CommandStep 24 Enter the HATCHEDIT commandon the command line as shown below.See Figure Step 24.Command: HATCHEDITSelect hatch object: P1
(Select the hatching pattern inside the ellipseof Part A. This will open the Hatch Editdialogue box.)
Figure Step 24
Figure Step 25A
Step 25 In the Angle and scale box change theAngle to 135 and the Scale to 2 as shown in FigureStep 25A. Then click OK. Notice the change to thehatching pattern as shown in Figure Step 25B.
Step 26 To edit the hatching pattern forPart B, double click the pattern as shown inFigure Step 26. That will open the Hatch Editdialogue box.
Figure Step 26
Step 27 On the pull-down list for Pattern, select Net.See Figure Step 27.
Step 28 In the Angle and scale box, change theAngle to 0 and the Scale to 3 as shown in Figure Step28A and then click OK. Note the change to thehatching pattern as shown in Figure Step 28B.
Figure Step 28A
Figure Step 28B
Step 29 Enter the BHATCHcommand and click the InheritProperties icon as shown inFigure Step 29A. Select the Nethatch pattern in Part B as shownin Figure Step 29B. Then selectinside the ellipse in Part D. SeeFigure Step 29C. Your drawingshould look as shown in FigureStep 29D.
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Figure Step 29A
Figure Step 29B Figure Step 29C
Step 30 Enter the commands shown below and notenow the hatching patterns will not display with fill off.See Figure Step 30A and 30B.Command: FILLEnter mode [ON/OFF] <ON>: OFFCommand: REGENRegenerating model.Command: FILLEnter mode [ON/OFF]<OFF>: ONCommand: REGENRegenerating model.Command:
The Inherit Properties icon in the Hatch and the Edit Hatch dialogue boxescan be very handy. Use it to select the type ofhatching you want to match from an existing hatchpattern on the drawing. It is a fast way to match onepattern with another without looking at the propertiesof the existing hatch.
The system variableSNAPBASE sets the originpoint for hatching patterns.The default is 0,0. On some
hatch patterns it is important that they start atthe right location to match the area they arefilling. Study the brick pattern on the house.To look correct, it should start with a full brickat the bottom left corner.
Command: BHATCHSelect Object: P1Command: SNAPBASEEnter new value for SNAPBASE<204.2871,-57.6588>: end of P2Command: BHATCHSelect Object: P3 2
BEFORE SNAPBASE
AFTER SNAPBASE
1
3
The Key Principles in Module 291. If you are using the Select object method to hatch, you must create the closed polyline
before executing the BHATCH command using the PLINE, PEDIT or BOUNDARYcommands. Since a circle or an ellipse is a closed object, they can also be used as aclosed polyline.
2. All hatch patterns are constructed using lines but the hatch pattern is created as a singleobject in the drawing. This helps to manipulate the hatch patterns and keep the drawingdatabase smaller. A hatching pattern can be exploded back into its individual lineobjects using the EXPLODE command..
3. An associative hatch will automatically adjust when the boundary that was used when itwas created is moved or changed. A nonassociative hatch remains the same size andin the same location regardless of the changes made to the hatch boundary.
4. The system variable SNAPBASE sets the origin point for hatching patterns.
Construction HintsDo your best to complete the lab exercise drawing without using the following hint(s). If you getstuck and can't complete it on your own, use the following hint(s) to help you.
Hint 1
If you have trouble visualizing the object and thesection view you have to draw, study the viewsbelow. The solid modeling views were done usingAutoCAD. Solid Modeling is taught in the AutoCAD3D Modules.
Construction HintsDo your best to complete the lab exercise drawing without using the following hint(s). If you getstuck and can't complete it on your own, use the following hint(s) to help you.
Front and Right Side Section View
Hint 1
To draw the teeth, see the five steps in Figure Hint 1. Step 1 - Draw one line of the teeth.Step 2 - Array the line 64 times. Step 3 and 4 - Add lines to create one tooth and the repeatpattern and then erase the remaining lines. Step 5 - Array the tooth 32 times.
Note: Color, Linetype, and Lineweight are all ByLayer unless otherwise instructed.
Layering Scheme
Objects on Layer Name Color Linetype LineweightConstruction Objects
Lot Lines
House, Driveway, and Patio
Hatch Boundary
Construction
Lot
House
Boundary
253
Green
Red
Blue
Continuous
Continuous
Continuous
Continuous
N/A
N/A
N/A
N/A
Dimensions and Labels Label White/Black Continuous N/A
Hatch PatternsInstructions:
Hatch 254 Continuous N/A
1. Since the object you will be drawing is large, you will have to scale the drawing titleblock larger than itis. Complete the following steps:A. Start a new drawing using the Module Template A3.B. Using the SCALE command and the base point of 0,0, scale the complete titleblock at a scale
factor of 100. In a future module, there will be a complete explanation of why this number is used.For now, just use the number given to you.
2, Draw the map shown below. The input is in millimeters but the dimensions are in meters, so becareful. 1 meter = 1000 millimeters
3. Label the lengths and items exactly as shown below. Pick a text height and font that looks good.Create your own style.
4. On the Boundary layer, create a boundary around each the areas as shown below.5. Insert the following hatch patterns in each area:
A.B.AR-CONCC.
D. Net at an angle of 45 degreesE. Gravel
F.AR-HBONEG.
Note: You will have to adjust the scaleof each hatching pattern. Insert themand then edit them until you they lookthe best on your drawing. If BHATCHwill not insert them at the scale youselected, change the scale until it will.
B
A
C
D
E
G
F
6. Find the following in Sq Meters.(answers in thekey):A. Area of House and Garage:
_____________B. Area of Patio(include wall), gravel area, and
grass area: ______________C. Area of driveway and sidewalk:
________________D. Percentage of lot covered by the house and
