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Technical Drawing Standards: Dimension Styles

The BS ISO Technical drawing Standard describes Five different dimension styles for us to choose from.

The first two, ‘Closed – Filled’ and ‘Closed – Blank’, would usually be used in Engineering. Oblique is often favoured by Architects. I’ve never seen anyone use Open 90° or Open 30°, except when sketching by hand.

There are a couple of Alternative terminators that have special meanings. A circle is indicative of an origin point. In the example of running dimensions below, all the dimension values spring from the same datum point.

BS ISO Dimension Terminators

The Point terminator is used for when the dimensions are too close together to allow room for an arrowhead. An Oblique stroke can be used instead.

BS ISO 129-1:2004 Technical Drawings –  Indication of dimensions and tolerances – Part 1: General Principles.