Hatching
Hatching is used to add shaded patterns
to objects and shapes within an Autocad drawing. Hatch patterns
can be used to indicate a material
to be used, such as a concrete hatch. Alternatively it could
be used to make an area of a drawing stand out.
A foundation detail with the Autocad default AR-CONC hatch
pattern applied.
The
hatch command 
can be found on the draw toolbar, or the draw drop down
menu. When entered, a dialogue box appears as shown below:
Type
- Custom hatch patterns can be created in Autocad. Leave
it set to predefined to use Autocad's built in hatch patterns.
Pattern
- This is where we select a hatch pattern from Autocad's
default list. Select 
to view more patterns. The hatch pattern palette appears,
with hatch patterns arranged under the categories: ;ANSI',
'ISO', 'Other Predefined' and 'Custom'. The most common
hatch patterns required are under the 'Other Predefined'
Tab.
Angle
- This sets the angle of the hatch pattern, the default
value is 0.
Scale
- This sets the size of the hatch pattern. This must be
set correctly dependant on if you are drawing in metres
or millimetres. A little trial and error is required to
obtain a suitable scale (See Preview below).
Pick
Points & Select Objects
- These are Autocad's two different methods of hatching
an area. Using pick point, clicking inside an area (such
as a rectangle) will result in the hatch pattern being applied
to all blank space within the boundary. Select object simply
hatches within a selected object.
Great care must be taken to ensure that the area to be hatched
is closed, and all line endpoints are meeting each other.
If a small gap is left open, the hatch command will fail,
usually with the error: Unable to hatch boundary.
Preview
- Enables a quick preview of the hatch before applying it,
letting us quickly change and preview settings before we
ok them. Very useful when trying different hatch scales.
Inherit
Properties - This command
enables the hatch settings of a hatch already in use in
the drawing to be brought into the boundary hatch dialogue
box.
Composition
- This is how Autocad is to treat objects to be hatched.
For the moment, leave it set to Associative.
Pick Point
The above hatch was created by using the pick point method.
The hatch stays within all the solid lines.
Select
Object
The above hatch was created by using the select object
command. The rectangle was selected, and as a result all
of the rectangle becomes hatched. Interestingly, if both
the hexagon and rectangle were selected (i.e BOTH boundaries)
then the hatch pattern would have had the same result as
in the above 'pick point' example.
Be careful to
ensure that there are no gaps in the boundary to be selected
(zoom in if required). Usually, this results in either unexpected
results, or a hatch error as shown below.
Have a go with the hatch command with the following Autocad
drawing file:
Lesson9.dwg
(Autocad 2000 file)
Lesson9r14.dwg
(Autocad 14 File)
Use the select
object method to apply the hatch pattern
AR-CONC (found
in Other Predefined in the hatch pattern palette) to the
concrete foundation. Use a hatch scale
of 1
and angle
0.
Use the pick point pattern
to apply the hatch pattern ANSI32
(Found in ANSI in the hatch pattern palette) to the bricks.
Use a hatch
scale of 3 and an angle
of 0.
Note:separate multiple areas can be selected with the pick
point method, all in one go!
Your finished
drawing should look like the one below:
Please report
any errors/omissions to
contact@autocadcentral.com.
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