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Define Hatch Boundaries

May 20, 2011

To create a hatch, you should define hatch boundaries first by means of selecting objects to be hatched or picking a point inside the desired object. A hatch boundary can be any combination of objects, such as lines, arcs, circles, and polylines, that forms an enclosed area.

To raise the speed of hatching a small area of a complex drawing, you can define a set of objects in the drawing. HATCH does not analyze objects that are not included in the boundary set.

Island is a concept representative to the closed area inside the hatched object. You can hatch the island and also retain its original state.

Objects can be hatched only if they are in a plane parallel to the XY plane of the current UCS. For the internal area of polylines with width and solid hatching, hatches can't be applied because of its unacceptable profiles.


Control the Hatching in Islands

You can specify methods of hatching objects in outermost boundary as normal, outer and ignore. Normal is the default hatch pattern, besides, you can view hatching results of different types in the Island detection option on Boundaries tab.


Normal

Hatch the pattern from the outer boundary to inside. Hatching process will be stopped when encounter inner crossing points, and continue hatching until second inner crossing point appears. So if counter from outer boundary of hatch area, the area separated by odd number crossing points will be hatched, on contrary the area separated by even crossing points will not be hatched.

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Outer

Hatch the pattern from the outer boundary to inside. For the hatching starts from two points of each hatch line, system will hatch from the outer most layer of configuration, and keep the internal blank. Hatching process will be stopped when encounter inner crossing points.


Ignore

Ignore internal objects, only hatches outer objects. The following example displays the results of hatching a complex entity with Normal, Outer, Ignore pattern individually:

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You can also remove any islands from the hatch area.

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Define Hatch Boundaries in Large Drawings

Generally, boundaries are defined by analyzing all the closed objects. It's time consuming to define boundaries through analyzing all the visible or partly visible objects when encounter complex drawings. In such cases you can save time hatching a small area in a complex drawing by defining a set of objects in the drawing to be used in determining the hatch boundary.

Boundaries are also available for applying different hatch patterns to islands in different area of the drawing. To avoid selecting the undesired hatch area, its required to enlarge the drawing. Once selected Existing set in Boundary set option on Other options tab, the objects used for defining boundaries will be highlighted.

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Create Unbounded Hatches

You can define a hatch boundary composed by multiple points manipulated from the draW_boundary option of -HATCH or -BHATCH command. System inquires for whether to retain boundaries when finish hatching, if choose not to retain boundaries, then create hatch pattern without boundaries.

For example, to define a boundary through specifying points, only a small part of the large area of the drawing will be hatched, hatching the large area without boundaries, shown as follows:

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Selecting objects for hatching

A hatch boundary can be defined by means of selecting any object, for example, a circle or rectangle. You can assign hatching to a single object or several objects at the same time.

You can add hatching to an area enclosed by selected objects to form the hatch boundary. The hatch is formed within the enclosed area, not the objects themselves. Once a hatch is created, it will be treated as a single object. And the object being hatched changes along with the hatch boundary if the hatch you create is associative.


To select objects for hatching

  1. Choose Draw > Hatch.

  2. From the Hatch dialog box, click the Island detection option, and then choose one of the following island:

  • Normal Areas separated from the outside of the hatched by an odd number of intersections are hatched.

  • Outer Only the outer object and its outer island are considered for hatching.

  • Ignore The entire object is considered for hatching, inner area will be ignored.

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Normal islands (A), with outer island (B), and with ignore islands (C).

  1. To keep any new objects that are created for drawing the boundary hatch, select the Retain Boundaries check box. Existing objects are always retained.

  2. In the Boundaries , click Add: Select objects.

  3. In the drawing, click the objects to be hatched individually, and then press Enter when done.

  4. In the Hatch dialog box, click OK.

Draw toolbar\

Command line BHATCH


Select an area for hatching

  1. Choose Draw > Hatch.

  2. From the Hatch dialog box, click the Island detection option, and then choose one of the following island:

  • Normal Areas separated from the outside of the hatched by an odd number of intersections are hatched.

  • Outer Only the outer object and its outer island are considered for hatching.

  • Ignore The entire object is considered for hatching, inner area will be ignored.

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Normal islands (A), with outer island (B), and with ignore islands (C).

  1. To keep any new objects that are created for drawing the boundary hatch, select the Retain Boundaries check box. Existing objects are always retained.

  2. In the Boundaries , click Add: Pick points.

  3. In the drawing, click inside the closed perimeter of a boundary, not on the boundary itself. If desired, continue clicking inside additional closed perimeters.

  4. To complete the selection, press Enter.

  5. In the Hatch dialog box, click OK.

Draw toolbar \

Command line BHATCH


Commands Reference

BHATCH: Fills an enclosed area or selected objects with a hatch pattern or gradient fill

BOUNDARY: Creates a region or a polyline from an enclosed area

DONUT: Draws filled circles and rings

HATCH: Fills an closed area or selected object with specified hatch pattern or gradient pattern.

HATCHEDIT: Modifies an existing hatch object

PLINE: Creates two-dimensional polylines

SOLID: Creates solid-filled triangles and quadrilaterals

System Variables Reference

HPBOUND: Controls the object type created by the BHATCH and BOUNDARY commands

PICKSTYLE: Controls the use of group selection and associative hatch selection


 

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