Basics · Technical drawing

Section views and hatching in technical drawings

7 min read · updated 3 Nov 2026

When a part has many holes, grooves or internal cavities, ordinary views fill up with dashed lines until nothing can be read. A section view solves this by imagining the part cut along a chosen plane and looking at the exposed face. Material the plane passes through is hatched with thin diagonal lines, so wall thicknesses and internal shapes become obvious.

Kinds of section

Kind	What it is	Use it when
Full section	Cut right through along one plane	The part is not symmetrical, or you need to see all of the inside
Half section	One half in section, the other half external, divided by a centre line	Symmetrical parts such as flanges, bushes, round covers
Local (broken-out) section	Only a small area is cut, bounded by a thin freehand line	One hole or groove needs showing, such as a tapped hole in a shaft
Revolved / removed section	The cross-section is turned 90° onto the view, or placed beside it	Cross-sections of arms, spokes, keyways or long shapes
Offset / aligned section	The cutting plane steps or bends to pass through several features	Holes that do not lie on one straight line

Cutting planes and labels

Draw the cutting plane on the view being cut, as a thin long-dash dotted line with short thick ends.
At each end add an arrow showing the viewing direction and a letter, such as A.
Label the section A–A (some standards write SECTION A-A). Further sections use B–B, C–C and so on.
A section in its normal projected position whose meaning is obvious — a half section of a symmetrical part, say — may not need a cutting plane.

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Hatching rules

Use thin continuous lines at 45° to the main outline or axis of the part.
Keep the spacing even, about 2–4 mm on paper, scaled to the area (closer for small areas, wider for large ones).
The same part gets the same angle and spacing everywhere in a section, even where its areas are separate.
Adjacent parts in an assembly alternate the direction (45° and 135°) or change the spacing so they can be told apart.
Very thin areas such as gaskets or thin sheet may be filled solid instead.
Never hatch through dimension text; leave a gap around it.

Parts not hatched even when cut lengthwise

Shafts, pins, rivets, screws, nuts, washers, keys, bearings' rolling elements, spokes and ribs cut along their length are drawn as external views without hatching. Hatching these solid items adds nothing and suggests they are hollow or thick.

Sections in DXCAD2D Online

Draw the cut shape as a closed area, making sure every corner meets (close gaps with Fillet radius 0).
Set a layer for hatching, press H and choose the 45° lines pattern. Set the spacing in the options box at the top right, or type the spacing and press Enter.
Click inside each cut area (the whole boundary must be on screen). Holes inside the area are left out automatically.
For an adjacent part in an assembly choose 135° lines to alternate the direction.
Draw the cutting plane as a line on a layer set to the centre line type, add arrows with leaders (LE) and the letter A, then place the text A–A under the section.
Click an existing hatch later to change its pattern or spacing.

Tip: if no hatch appears, the area is not closed or part of it is off screen. Press Z to see the whole drawing and try again.

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