Using our imagination we can sometimes make a reasoned guess as to what may be

concealed inside an object. We may even be lucky enoughto have a magic key to reveal

information as to what islocked up inside the safe

The key to revealing hiddeninformation in a drawing

is to know the British Standard rules on sectioning

In real life if we want to find whatthe inside of donut is like we cut through it to see what is inside.

When the donut has been cut thesurfaces where the knife has passedthrough are clearly visible.

In graphic communication where a surfacehas been cut to reveal information then thatsurface representing a specific material or materials is cross hatched as indicated.

X X

PLAN

SECTION XX

cutting plane line

Cutting Plane lines should clearly show where a section has been is taken

The drawings below show 3 views of a donut. A section XX is required to reveal that the centre of the donut is hollow. The section has been taken centrally through the PLAN.

When the section line ‘cuts’ through the centre of the donut it also passesthrough an ‘air gap’ as wellas solid material.

When a section line passes through solid material theseareas are cross hatched at 45º

Cross hatching lines are evenly spaced and in thesame direction when thematerial is the same

N.B. Air gaps are not cross hatched

END ELEVATION

PLAN

ELEVATION

1. Draw the Magic 45º from the corner of the ELEVATION.

2. Project the the breadth of the PLAN onto the Magic 45º then down to the ground line.

Ground Line

3. Project the height of the ELEVATION across to the END ELEVATION.

4. Project the top and bottom of the hole across to the END ELEVATION.

5. Darken the outline and the two lines to represent the top and bottom of the hole.

6. Cross hatch the top and bottom areas at 45º to show the cut surfaces of the section.

SECTION XX

X

X

X

Opposite shows a ‘cutting plane’and a view showing the cut surfaces.

A cutting plane line is positioned to takea section through the cab, wheels and axle of a toy truck.

The END ELEVATIONis shown as Section XX.

Parts A and B arenot sectioned asthey are air gapsair gaps.

The axle is not sectioned as it hasno information to reveal.

The wheels arecross hatched inopposite directionsto the main body.

PLAN

ELEVATIONEND ELEVATION

SECTION XX

PLAN

ELEVATION

EXPLODED VIEW

SECTION XX

A cutting plane line is positioned to takea section through the lid and base of the salt shaker.

The lid and base are cross hatched in opposite directions but with thesame spacing

Air gaps are not crosshatched.

Hidden detail is nevershown in a sectionedview.

Most of the toy train is made from the same kind of wood. The wheels are made from plastic.

Cut surfaces are represented with cross hatchinglines, evenly spaced, at 45º

ELEVATIONSECTION XX

(Ready for Cross Hatching)

Cutting plane lines indicate wherea section is to be taken. Two pieces of the

same material arerepresented withsame spacing butopposite in direction.

X

X

Letters are used to identifythe cutting plane line.

ELEVATIONSECTION XX

The pictorial view shows how theaxle is supported underneath.

X

X

Air GapsAir Gaps are not sectioned

Nuts, bolts, washers, screwsor shafts (axles) do not haveto be shown in section.

The example oppositeshows how a section iscross hatched when onematerial is sandwichedbetween two pieces of another material.

Using these rules SECTION XX would be crosshatched in the following way

X

XSECTION XX

Shelf SupportShelf Support

When a cutting plane line passesthrough a thin support websupport web along its length then the webweb is not cross hatched in section.

Webs are used to strengthenfitments like brackets etc.