Metric Isometric Drawing

• Metric scale is expressed as a ratio, that is, a proportional relationship of like units (i.e. 1 millimeter equals 200 millimeters, or, 1 centimeter equals 200 centimeters), unlike imperial scale, or foot-inch scale, which is expressed as unlike units (i.e. 1 inch equals 1 foot, or one-sixteenth inch equals one foot). Imperial scale can be expressed as a scale ratio by converting to like units (i.e 1/16”=1’-0” becomes 1”=192” or 1:192 which is similar to the metric 1:200 scale).

• The metric scale is easier to read than the architect’s scale in that there are no fractions of units. All units are read as either millimeters, centimeters or meters. A 1:100 scale can be used for a 1:10 scale by moving a decimal place over and reading 1 meter as 100 millimeters. 25.4 mm = 1” (or, 100 mm ≈ 4”).

• Millimeters are commonly used as dimensional units in furniture design, and when units are expressed uniformly, there is no need to notate the units after the dimension. Here, the units are all noted in millimeters and the dimensions are expressed along the isometric axes.

• The isometric view can be constructed by first converting the orthographic plan view into an isometric plan view and using that to project into the vertical axis (the Z axis).

• The dimensions can be measured directly along the X, Y or Z axis from the orthographic plan, but other dimensions will not be accurate (i.e. diagonals).

• Once the plan of the object is laid out (lightly) isometrically on the bottom plane along the X and Y axes, it becomes relatively easy to project all the heights of the object up into the vertical axis, the Z axis – based upon the orthographic elevation heights.

• An isometric provides a relaxed view of both axes of a space and can be constructed relatively easily in order to depict spatial relationships with accurate, scalable dimensions. Pulling the roof up from the space, or the wall out, allows one to see both the interior space and the exterior envelope of a construction.