Scale Bar CAD Blocks for 1:50, 1:100 and 1:200

Scale bar CAD block in real model units

A scale bar is the one symbol that must not be resized. These blocks are drawn in the same millimetres as the plan, so a 1 m segment is 1,000 mm long in the model. Insert one at a factor of 1 in model space next to the plan and it measures the plan exactly. When someone prints the sheet at A3 instead of A1, or zooms a PDF on screen, the bar shrinks or grows with the drawing and still tells the truth. A written scale such as 1:100 does not.

Each bar is a chequered strip in two rows, with zero a full segment from the left end. The segment to the left of zero, the heel, is split into smaller parts for reading short lengths. Figures and the unit m are text on G-ANNO-TEXT, the outline is on G-ANNO-SYMB and the fills on G-ANNO-SYMB-DETL.

Graphic scale for 1:50, 1:100 and 1:200 drawings

The 1:50 bar runs from 0 to 5 m in 1 m segments, with a 1 m heel in five parts of 0.2 m. With its heel it plots at 120 mm. The block measures 6,343 x 400 mm including the figures.

The 1:100 bar runs from 0 to 10 m in 1 m segments, with the same heel of five 0.2 m parts. It plots at 110 mm and the block is 11,791 x 800 mm.

The 1:200 bar runs from 0 to 20 m in 2 m segments, with a 2 m heel in four parts of 0.5 m. It also plots at 110 mm and the block is 23,581 x 1,600 mm.

In all three the figures plot 2.5 mm high, which is 125, 250 and 500 mm in the model. Pick the bar that matches the scale of the view. A 1:50 bar on a 1:100 plan still measures correctly, but it plots at half the intended size, with 1.25 mm figures.

Placing the scale bar in model space or on the layout

The simplest place is model space, beside the plan, so it appears in the same viewport. If the plan is shown in several viewports at different scales, give each one its own bar.

If you prefer the bar on the sheet in paper space, insert it there at a factor equal to the viewport scale, 0.01 for a 1:100 viewport. It then measures that viewport only, so keep it close to the view it belongs to. Do not use annotative scaling for a scale bar, because a bar that changes size with the annotation scale no longer matches the drawing.

The drawing is in millimetres. In a drawing set up in metres, AutoCAD converts the file on insertion when its insertion units are set, so the 1 m segment still reads 1 m. The north arrows and other symbols are in the AutoCAD symbols collection, and the guide to inserting a CAD block covers the insertion steps.