Cross section (geometry)

A sectional drawing, section or even a short cut is a representation in the form of drawings. You will also plan drawing or short crack called, of which the floor plan and elevation terms derived (the view ). Depending on the section plane is referred to the drawings as a longitudinal or cross-sectional ( rarely also the floor plan floor plan section).

A cross-sectional view used to show hidden inner contours, materials and structures of a body. If necessary, different sections must be placed by a body to represent all the relevant details in several cut surfaces can.

Areas of application

Sectional drawings and presentations come in many areas. In technical drawing in the representation of equipment and parts in mechanical engineering or in construction ( building, civil engineering ); in the representation of buildings in architecture; in the graphic presentation of equipment for amateurs; in the science fiction scene, where fans or authors represent fictional spaceships and space stations; in biology at the representation of the structure of flora and fauna; in the representations of the layers in the soil in geology and archeology; in medicine for the tomographic imaging of the human body and so on.


With a classic cut drawings, the edges are thicker represented as the contours of the elements that you see in the view. The cut surfaces are often flat or filled with hatching. Depending on the application, there are different rules for section drawings.

In mechanical engineering, for example, special rules apply to the display of threads cut, holes and fittings as well as for their dimension.

Conventions are also in construction. For the presentation of the drawings in the official planning application procedures apply ( Bauvorlagenverordnung )

If the cutting plane passes through several bodies, the cut surfaces are to be represented by hatching in different directions. To identify different materials (metal, concrete, masonry, wood, textiles, plastics, and others) hatching of different types are used ( eg, lines, cross lines, dashed lines, dotted shading, inter alia, in various line widths and - intervals, halftones, and surfaces in different greyscale or color ).

Longitudinal (parallel to the axis) cut rotary body ( eg the three- body plant seeds ) are represented by convention as a non-sectioned body ( in the view ); the axis of which in phantom line drawing. Before the cut -plane edges or underlying, hidden contours can be displayed, then with dashed lines. Most often, the recognizable next to the cut part parts that are behind the cut line (with very thin lines ) is also shown. There, lying visible surfaces can be represented naturalistically - even photo realistic (CAD, animation).

On the other hand, such a view of drawing are also presented with neutral shown sectional area ( as a continuous uniform hatching, in a two-dimensional filling or blackened " Black Plan", " blackened section "). Here are different materials not shown in the illustration.

Besides the classical two-dimensional sectional drawings there is also perspective drawings that are often generated from the computer -generated models out. They are often easier to understand for the layman. Occasionally sectional drawings are also blown up by individual regions are shown for clarity added and not conceal it. One then speaks of exploded drawings.


Sectional perspective drawing

Sectional view of a tooth in the Biology

Three-dimensional sectional drawing in biology

Sagittal section image of a knee joint by MRI