ENGT122 - CADI Chapter 13 - Hatching. What is Hatching? Hatching refers to filling an enclosed boundary with a repetitive pattern of formatted line segments

ENGT122 - CADIENGT122 - CADI

Chapter 13 - HatchingChapter 13 - Hatching

What is Hatching?What is Hatching?

Hatching refers to filling an enclosed boundary with a Hatching refers to filling an enclosed boundary with a repetitive pattern of formatted line segments.repetitive pattern of formatted line segments.

Hatching in AutoCAD is the same as creating section lines Hatching in AutoCAD is the same as creating section lines in drafting.in drafting.

Typically used to identify cut region of a part in a Typically used to identify cut region of a part in a Section Section View.View.

Also used to distinguish parts or identify materials in Also used to distinguish parts or identify materials in sectioned assembly drawings.sectioned assembly drawings.

Example - HatchingExample - Hatching

Examples of hatching Examples of hatching section views in section views in AutoCADAutoCAD

DEMO 1:DEMO 1:

Load file Load file Demo1.dwgDemo1.dwg..

Create a quick hatch for reference.Create a quick hatch for reference.

Hatch PatternsHatch Patterns

AutoCAD provides numerous AutoCAD provides numerous predefined hatch patterns.predefined hatch patterns.

Each hatch pattern is defined Each hatch pattern is defined by individual line segments with by individual line segments with specified specified patternpattern, , angleangle, and , and spacingspacing..

For convenience, the line For convenience, the line segments in each hatch are segments in each hatch are stored and treated as a group. stored and treated as a group. EXPLODEEXPLODE will break the hatch will break the hatch into individual segments.into individual segments.

patternpattern

spacingspacing

angleangle

Hatch BoundaryHatch Boundary

Hatching should be performed on drawing regions Hatching should be performed on drawing regions completely enclosed by a boundary – completely enclosed by a boundary – Hatch BoundaryHatch Boundary..

The The Hatch BoundaryHatch Boundary may consist of lines, arcs, circles, or may consist of lines, arcs, circles, or other entities.other entities.

AutoCAD does not require the objects comprising a AutoCAD does not require the objects comprising a Hatch BoundaryHatch Boundary to be connected point to point. Any to be connected point to point. Any intersecting entities which form an enclosure will work.intersecting entities which form an enclosure will work.

Hatch BoundaryHatch Boundary

Creating a HatchCreating a Hatch

Command to create hatch patterns;Command to create hatch patterns;

HHATCHATCH Uses graphical dialog box.Uses graphical dialog box. Boundary defined by;Boundary defined by;

Selecting point within an enclosed region; or by Selecting point within an enclosed region; or by Selecting boundary objects.Selecting boundary objects.

Allows preview of hatch pattern.Allows preview of hatch pattern. Allows associative hatching.Allows associative hatching.

HATCHHATCH

HATCH can be invoked by 3 methods;HATCH can be invoked by 3 methods;

Command:Command: HHATCHATCH

DDMenu:DDMenu: DrawDraw >> Hatch…Hatch…

Draw ToolbarDraw Toolbar

All 3 bring up the HATCH dialog box.All 3 bring up the HATCH dialog box.

Hatch PatternsHatch PatternsSelecting a Hatch Pattern:Selecting a Hatch Pattern:

TYPETYPE – sets the hatch pattern type. – sets the hatch pattern type. Predefined Predefined - Specifies a - Specifies a

standard pattern supplied with standard pattern supplied with AutoCAD. AutoCAD. AngleAngle and and ScaleScale can can be controlled by user.be controlled by user.

User DefinedUser Defined - Creates a user - Creates a user defined pattern of lines. defined pattern of lines. Covered in CAD III.Covered in CAD III.

CustomCustom - Specifies a custom - Specifies a custom pattern created by user and pattern created by user and stored in a hatch file (.pat). stored in a hatch file (.pat). Covered in CAD III.Covered in CAD III.

Hatch PatternsHatch Patterns

PredefinedPredefined Hatch Pattern:Hatch Pattern:

Drop down shows listing of available Drop down shows listing of available hatch pattern names.hatch pattern names.

[…][…] Displays graphical image of Displays graphical image of available patterns according to available patterns according to groupings;groupings; ANSIANSI – patterns defined by – patterns defined by American American

National Standards InstituteNational Standards Institute.. ISOISO – patterns defined by – patterns defined by

International Standards OrganizationInternational Standards Organization.. Other PredefinedOther Predefined – other AutoCAD – other AutoCAD

Patterns.Patterns. CustomCustom – custom pattern from user – custom pattern from user

file.file.

Typically use thisTypically use thisPattern (ANSI31).Pattern (ANSI31).

Hatch Pattern DefinitionsHatch Pattern Definitions

Effect of Angle & Scale:Effect of Angle & Scale:

The hatch pattern line The hatch pattern line segment lengths, spacing, segment lengths, spacing, and angle are predefined.and angle are predefined.

However, Angle and Scale However, Angle and Scale can be altered.can be altered.

AngleAngle – rotates hatch with – rotates hatch with respect to definition respect to definition angleangle..

ScaleScale – scales hatch – scales hatch segment length & line segment length & line spacing with respect to spacing with respect to defined length & spacing.defined length & spacing.

Scale=1Scale=1Angle=45Angle=45

Scale=1Scale=1Angle=0Angle=0

Scale=0.5Scale=0.5Angle=45Angle=45

Scale=0.5Scale=0.5Angle=0Angle=0

DEMO 2A:DEMO 2A:

Load file Load file Demo2.dwgDemo2.dwg

Show various predefined patterns.Show various predefined patterns.

Show effect of Angle and Scale.Show effect of Angle and Scale.

Show Exploding Hatch.Show Exploding Hatch.

Selecting BoundariesSelecting Boundaries

Hatch Boundaries can be Hatch Boundaries can be selected by 2 methods;selected by 2 methods; Pick PointsPick Points – AutoCAD – AutoCAD

automatically constructs automatically constructs a boundary from the a boundary from the smallest enclosure smallest enclosure surrounding the picked surrounding the picked point.point.

Select ObjectsSelect Objects – requires – requires selecting the objects to selecting the objects to be hatched.be hatched.


Pick Points:Pick Points:

Constructs a boundary from the Constructs a boundary from the smallest enclosure surrounding the smallest enclosure surrounding the picked point.picked point.

Uses Uses island detectionisland detection to remove to remove regions completely enclosed within regions completely enclosed within the boundary.the boundary.

Pick Pick PointPoint





Multiple pick points can be used to add Multiple pick points can be used to add islandsislands or or additional areas to the hatch region.additional areas to the hatch region.

Pick Pick PointPoint Pick Pick

PointsPoints

Exercise 1:Exercise 1:

Create the RED circles Create the RED circles and rectangle shown in and rectangle shown in AA. Then make 2 . Then make 2 additional copies as additional copies as shown in green.shown in green.

Use Use Pick PointsPick Points to hatch to hatch each figure as shown in each figure as shown in BB using the ANSI31 using the ANSI31 hatch pattern. Use the hatch pattern. Use the ScaleScale option to get a option to get a reasonable hatch reasonable hatch spacing.spacing.

Figure AFigure A

Figure BFigure B

Island DetectionIsland Detection

Expanding the Hatch Dialog box Expanding the Hatch Dialog box gives access to some Island gives access to some Island Detection Options… Detection Options…


Normal IslandNormal Island Outer IslandOuter Island Ignore IslandIgnore Island

Pick PointsPick Points


Selection Short-cut Menu:Selection Short-cut Menu:

The The Island DetectionIsland Detection Options can Options can also be accessed through a also be accessed through a shortcut menu (Right click mouse shortcut menu (Right click mouse during point selection). during point selection).

RecommendationRecommendation:: Only use the Only use the EnterEnter button on the shortcut menu. button on the shortcut menu. There are bugs associated with the There are bugs associated with the shortcut menu – particularly with the shortcut menu – particularly with the PreviewPreview button. Use Preview on the button. Use Preview on the main dialog box.main dialog box.

Don’t Use Shortcut PreviewDon’t Use Shortcut Preview!!!!!!

Avoid this - bugAvoid this - bug


Make 3 copies of the circle Make 3 copies of the circle and ellipse pattern as and ellipse pattern as shown in shown in AA. They should . They should be perfectly centered.be perfectly centered.

Use a single Use a single Pick PointPick Point with with the correct the correct Island Detection Island Detection OptionOption to hatch each figure to hatch each figure as shown in as shown in BB. Use the . Use the ANSI31 hatch pattern and ANSI31 hatch pattern and the the ScaleScale option to get a option to get a reasonable hatch spacing.reasonable hatch spacing.

Figure AFigure A

Figure BFigure B


Select ObjectsSelect Objects

Constructs a boundary from Constructs a boundary from selected objects.selected objects.

Does not recognize interior Does not recognize interior objects unless they are objects unless they are selected as well.selected as well.

More limiting than Pick Point More limiting than Pick Point method – not all hatch method – not all hatch patterns can be achieved.patterns can be achieved.



Examples of Select Object MethodExamples of Select Object Method

Select ObjectSelect Object Select ObjectSelect Object Select ObjectSelect Object


Make 3 copies of the circle & rectangle pattern as shown in Make 3 copies of the circle & rectangle pattern as shown in AA. .

Use Use Select ObjectsSelect Objects to hatch each figure as shown in to hatch each figure as shown in BB using using the ANSI31 hatch pattern. Use the the ANSI31 hatch pattern. Use the ScaleScale option to get a option to get a reasonable hatch spacing.reasonable hatch spacing.

Figure AFigure A

Figure BFigure B

Miscellaneous Hatch OptionsMiscellaneous Hatch Options

Remove BoundariesRemove Boundaries – allows – allows boundaries such as islands to boundaries such as islands to be removed from selection set. be removed from selection set.

View SelectionView Selection – –temporarily closes dialog temporarily closes dialog box so object selection box so object selection can be viewed.can be viewed.

Miscellaneous Hatch OptionsMiscellaneous Hatch Options

Inherit PropertiesInherit Properties – allows – allows hatch pattern properties hatch pattern properties from a hatched object to from a hatched object to be transferred to another be transferred to another selected objects.selected objects.

AssociativeAssociative – hatch pattern – hatch pattern will update if boundary will update if boundary geometry is changed.geometry is changed.

Create Separate HatchesCreate Separate Hatches - - for multiple selections, for multiple selections, each hatch is is treated as each hatch is is treated as a separate object.a separate object.

DEMO 3:DEMO 3:


Show Show AssociativeAssociative vs. vs. Nonassociative Nonassociative Hatch pattern.Hatch pattern.

Show Show Create Separate HatchCreate Separate Hatch

Show Show Inherit PropertiesInherit Properties

Exercise 5A:Exercise 5A:

Create the 3 green rectangles as shown.Create the 3 green rectangles as shown.

Then hatch them using the hatch patterns indicated…don’t Then hatch them using the hatch patterns indicated…don’t worry about the color but note the angle on the 1worry about the color but note the angle on the 1stst and 3 and 3rdrd hatch pattern. Make sure the hatch pattern. Make sure the Associative Associative option is selected. option is selected.

Predefined ANSI 31Predefined ANSI 31

Predefined AR-B816CPredefined AR-B816C

Predefined ANSI31Predefined ANSI31

Exercise 5B:Exercise 5B:

Create 3 overlapping Create 3 overlapping circles as shown in circles as shown in FigFig BB..

Then hatch them using Then hatch them using the the Inherit OptionInherit Option to to transfer the hatch transfer the hatch patterns from patterns from FigFig AA..

Figure AFigure A

Figure BFigure B

Exercise 5C:Exercise 5C:

Use Grips to adjust the Use Grips to adjust the image in image in Fig AFig A to that to that shown in shown in Fig BFig B. Note . Note how Associative Hatch how Associative Hatch works!works!

If you have problems If you have problems creating the small circle, creating the small circle, try making it larger try making it larger instead.instead.

Figure AFigure A

Figure BFigure B

Hatching Around TextHatching Around Text

For hatching, AutoCad treats For hatching, AutoCad treats text like any other object.text like any other object.

The same rules for The same rules for Island Island DetectionDetection and and SelectionSelection still still apply.apply.

This prevents section lines This prevents section lines (hatch pattern) from overlaying (hatch pattern) from overlaying text if treated properly…as you text if treated properly…as you remember from Drafting this is remember from Drafting this is usually desired.usually desired.

If If Object SelectionObject Selection is used, the is used, the text as well as the geometry text as well as the geometry must be selected to prevent an must be selected to prevent an overlay.overlay.

AutoCAD will overly Mtext if Object select is used incorrectly or Island Detection is ignored.

and Dtext

or Dtext

If treated properly, AutoCAD won't overly Mtext with a hatch.

Editing HatchesEditing Hatches

Once created, a hatch can be edited to change most all of Once created, a hatch can be edited to change most all of its attributes except for the boundary.its attributes except for the boundary.

Editable items include;Editable items include; Change PatternChange Pattern Change AngleChange Angle Change ScaleChange Scale Change Composition from Associative to Nonassociative, Change Composition from Associative to Nonassociative,

but not vice versa.but not vice versa. Change Island Detection Style (this may change the Change Island Detection Style (this may change the

hatch area depending if islands are present).hatch area depending if islands are present).


Methods to initiate a Hatch Edit:Methods to initiate a Hatch Edit:

Select hatch, then right click mouse and Select hatch, then right click mouse and select select Hatch EditHatch Edit from the short-cut menu. from the short-cut menu.

Double-ClickDouble-Click directly on the hatch object. directly on the hatch object. This is the quickest & easiest method.This is the quickest & easiest method.

Both methods bring up the Boundary Both methods bring up the Boundary Hatch dialog box where edit changes can Hatch dialog box where edit changes can be made.be made.

Short-Cut MenuShort-Cut Menu

Final NotesFinal Notes

For future assignments use the following settings:For future assignments use the following settings:

Section lines (ANSI31 pattern – adjust angle as necessary):Section lines (ANSI31 pattern – adjust angle as necessary): Line weight = Line weight = 0.35 mm0.35 mm Color = Color = CyanCyan Linetype = Linetype = ContinuousContinuous

Cutting Plane Lines:Cutting Plane Lines: Line weight = Line weight = 0.7 mm0.7 mm Color = Color = MagentaMagenta Cutting Plane Linetype = Cutting Plane Linetype = HiddenHidden or or PhantomPhantom with with

CELTSCALE adjusted to get proper segment lengths. CELTSCALE adjusted to get proper segment lengths. View Arrows = View Arrows = ContinuousContinuous lines. Use lines. Use PolylinePolyline to create to create

arrow. Length to width ratio = 3.arrow. Length to width ratio = 3.

End Lesson 28End Lesson 28

The End!The End!

RETIRED RETIRED MATERIALMATERIAL

Example - HatchingExample - Hatching

Example of hatching section view in an Assembly.Example of hatching section view in an Assembly.

Hatch PatternsHatch PatternsSelecting a Hatch Pattern:Selecting a Hatch Pattern:

TYPETYPE – sets the hatch pattern type. – sets the hatch pattern type. Predefined Predefined - Specifies a - Specifies a

standard pattern supplied with standard pattern supplied with AutoCAD. AutoCAD. AngleAngle and and ScaleScale can can be controlled by user. be controlled by user.

User DefinedUser Defined - Creates a pattern - Creates a pattern of lines based on the current of lines based on the current linetype in your drawing. linetype in your drawing. AngleAngle and and SpacingSpacing can be controlled can be controlled by user. by user. DoubleDouble creates creates additional lines at 90additional lines at 90 to first set. to first set.

CustomCustom - Specifies a custom - Specifies a custom pattern created by user and pattern created by user and stored in a hatch file (.pat). stored in a hatch file (.pat). Won’t need this until CAD III.Won’t need this until CAD III.

Behind the SceneBehind the SceneHow Hatch Works:How Hatch Works:

AutoCAD creates the first hatch line of infinite length AutoCAD creates the first hatch line of infinite length through an origin specified in the hatch definition.through an origin specified in the hatch definition.

Additional infinite hatch lines are then offset from first (DY). Additional infinite hatch lines are then offset from first (DY).

Using the user selected hatch boundary, the intersection of Using the user selected hatch boundary, the intersection of the boundary and the infinite hatch lines are identified. the boundary and the infinite hatch lines are identified.

All hatch segments outside the boundary are then turned All hatch segments outside the boundary are then turned off.off.

(X-origin, Y-origin)(X-origin, Y-origin)

DY offsetDY offset

First hatch lineFirst hatch line

External External hatch hatch turned offturned off

Full ScreenFull Screen

Hatch Pattern DefinitionsHatch Pattern Definitions

User Defined Hatch:User Defined Hatch:

Uses the linetype set for the current layer.Uses the linetype set for the current layer.

User specifies User specifies AngleAngle and hatch line and hatch line SpacingSpacing. .

SelectingSelecting Double Double creates additional lines at 90 creates additional lines at 90 to first set to first set

DEMO 2B:DEMO 2B:


Show how to make a User Defined Show how to make a User Defined Hatch pattern.Hatch pattern.

Exercise 4:Exercise 4:Create the circle and rectangle pattern shown in Create the circle and rectangle pattern shown in AA. .

Create a new layer with linetype=hidden and color=yellow, Create a new layer with linetype=hidden and color=yellow, then make it current.then make it current.

Use Use Select ObjectsSelect Objects to hatch the figure as shown in to hatch the figure as shown in B B using a using a User DefinedUser Defined hatch with an angle of -30 hatch with an angle of -30. Adjust . Adjust SpacingSpacing to to achieve a pattern as shown.achieve a pattern as shown.

If necessary, use the line scale commands (If necessary, use the line scale commands (LTSCALELTSCALE) to ) to adjust dash length.adjust dash length.

Figure AFigure A Figure BFigure B

AS TIME PERMITS


Selection Short-cut Menu:Selection Short-cut Menu:

Right clicking the mouse during point Right clicking the mouse during point selection displays a short-cut menu.selection displays a short-cut menu. To remove selection boundaries.To remove selection boundaries. Changes Island detection methodChanges Island detection method Allows Preview, but has a bug!Allows Preview, but has a bug!


Normal IslandNormal Island Outer IslandOuter Island Ignore IslandIgnore Island

Avoid this - bugAvoid this - bug

Advanced TabAdvanced Tab

The Advanced Tab allows some additional options.The Advanced Tab allows some additional options.

Island Detection Style: Island Detection Style: allows Island Detection allows Island Detection Default to be set.Default to be set.

Object Type: Object Type: determines determines object type created from object type created from boundary (boundary (polylinepolyline or or regionregion) and whether its ) and whether its retained.retained.

Boundary Set: Boundary Set: sets items to sets items to consider for boundary.consider for boundary.

Island Detection Toggle: Island Detection Toggle: island detection on or off.island detection on or off.

Includes IslandsIncludes IslandsExcludes IslandsExcludes Islands

Advanced TabAdvanced Tab

Review of Island Review of Island Detection StylesDetection Styles

NormalNormal OuterOuter IgnoreIgnore

*Note: white arrows indicate pick point.



Constructs a boundary from Constructs a boundary from selected objects.selected objects.

Does not recognize interior Does not recognize interior objects unless they are objects unless they are selected as well.selected as well.

More limiting than Pick Point More limiting than Pick Point method – not all hatch method – not all hatch patterns can be achieved.patterns can be achieved.



Examples of Select Object MethodExamples of Select Object Method

Select ObjectSelect Object


Select ObjectSelect Object Select ObjectSelect Object

Select ObjectSelect Object

Can’t recreate Can’t recreate the Pick Point the Pick Point hatch patternhatch pattern



Multiple pick points can be used to Multiple pick points can be used to add add islandsislands to the hatch region. to the hatch region.

AutoCAD creates a polyline to AutoCAD creates a polyline to represent the boundary formed by represent the boundary formed by the enclosure and islands.the enclosure and islands.

By default the polyline is deleted By default the polyline is deleted after the hatch is created. But it after the hatch is created. But it may be retained through settings may be retained through settings in the in the AdvancedAdvanced tab. tab.


Pick Pick PointsPoints

DEMO:DEMO:


Show Show Retained Object Retained Object option and option and whether polyline or region is retained.whether polyline or region is retained.

Gradient TabGradient Tab

Provides color shading for graphical enhancement.Provides color shading for graphical enhancement.

Demonstrate.Demonstrate.

AS TIME ALLOWS

AS TIME ALLOWS


Use the Gradient tab to create a self portrait or a Use the Gradient tab to create a self portrait or a portrait of your neighbor!portrait of your neighbor!


Methods to initiate a Hatch Edit:Methods to initiate a Hatch Edit:

Command:Command: HATCHEDITHATCHEDIT

DDMenu:DDMenu: ModifyModify >>ObjectObject >>HatchHatch

Both methods re-invoke the Boundary Both methods re-invoke the Boundary Hatch Dialog box where edit changes Hatch Dialog box where edit changes can be made.can be made.


Hatch Edit by Grips:Hatch Edit by Grips:

GripsGrips can be used to modify an object on the boundary of can be used to modify an object on the boundary of an an AssociativeAssociative hatch, and the hatch will update accordingly. hatch, and the hatch will update accordingly.

Words of caution:Words of caution: If the geometry is modified to the point where the original If the geometry is modified to the point where the original

boundary objects are no longer the edited boundary, the boundary objects are no longer the edited boundary, the edit will fail and AutoCAD will issue the message: edit will fail and AutoCAD will issue the message: Hatch Hatch boundary associativity removed.boundary associativity removed.

The boundary must remain enclosed or the edit will fail.The boundary must remain enclosed or the edit will fail. If the If the Retain BoundariesRetain Boundaries option was chosen during hatch option was chosen during hatch

creation, the hatch will associate with the Polyline creation, the hatch will associate with the Polyline boundary only – the polyline can be successfully edited, boundary only – the polyline can be successfully edited, but the original boundary objects are no longer but the original boundary objects are no longer associated.associated.

DEMO:DEMO:

Load file Load file Demo2.dwgDemo2.dwg..

Show editing by grips for associative hatch with Show editing by grips for associative hatch with No No Retained BoundaryRetained Boundary..

Show result of editing hatch with Show result of editing hatch with Retained BoundaryRetained Boundary. .

No Retainfor Boundary

BoundaryRetained


Other editing commands such as Other editing commands such as CopyCopy, , MirrorMirror, , MoveMove, , ScaleScale, and , and StretchStretch can be used with hatched objects. can be used with hatched objects.

Associativity will be maintained as long as the hatch Associativity will be maintained as long as the hatch andand allall boundary objects are selected during the edit. boundary objects are selected during the edit.

If the hatch is If the hatch is EXPLODEDEXPLODED, associativity will be lost and , associativity will be lost and each segment in the hatch pattern will become a each segment in the hatch pattern will become a separate object.separate object.

Final NotesFinal Notes

A Hatch pattern is always created on the currently active A Hatch pattern is always created on the currently active layer.layer.

Hatch patterns should be kept on separate layers to allow Hatch patterns should be kept on separate layers to allow toggling on and off. toggling on and off.

System variable System variable FILLMODEFILLMODE can also be used to toggle all can also be used to toggle all hatch displays on or off.hatch displays on or off. If If FILLMODEFILLMODE = 0, hatch not displayed = 0, hatch not displayed If If FILLMODEFILLMODE = 1, hatch is displayed = 1, hatch is displayed

FILLMODE requires regeneration FILLMODE requires regeneration REGENREGEN to display properly. to display properly.

Even when the hatch is not displayed, the hatch boundary can Even when the hatch is not displayed, the hatch boundary can be edited, and the hatch will update accordingly.be edited, and the hatch will update accordingly.


Hatch Edit by PROPERTIES Command:Hatch Edit by PROPERTIES Command:

A hatch can also be edited using the A hatch can also be edited using the PROPERTIESPROPERTIES command. command. Command:Command: PROPERTIESPROPERTIES Or select hatch, then right click mouse and select Or select hatch, then right click mouse and select PropertiesProperties

from the short-cut menu.from the short-cut menu.

Short-Cut MenuShort-Cut Menu

Items with white Items with white background in the background in the Properties dialog box Properties dialog box can be edited. Items can be edited. Items with gray background with gray background are locked. are locked.

Documents

ENGT122 - CADI Chapter 13 - Hatching. What is Hatching? Hatching refers to filling an enclosed boundary with a repetitive pattern of formatted line segments