Draft:Decimetric Projection

An example of a cube in Decimetric Sketching (10° from the Horizontal)

Decimetric projection is a method of visually representing three-dimensional objects in two dimensions in technical and product design. It is a form of axonometric projection, where the object is rotated along its axes to reveal multiple sides. Decimetric projection is similar to isometric projection, but differs in the angle at which the axes are oriented relative to the horizontal. In decimetric projection, the axes are drawn at 10° from the horizontal, instead of the 30° used in isometric projection.

Overview

In decimetic projection, the three coordinate axes appear equally foreshortened and the angle between any two axes is 120°, as in isometric projection. Nevertheless, the visual difference lies in orientation: whereas isometric projections use a 30° angle from the horizontal for receding axes, decimetic projection uses a shallower 10° angle. This offers a perspective where the depth axis is less steep, creating a more natural-appearing view in some objects, particularly product design uses.

An example of a cube, Cylinder, and Triangular prism in Decimetric Sketching (10° from the Horizontal)

Since all three axes are scaled equally, measurements can be made directly and uniformly, making the projection useful for technical purposes. The name "decimetic" comes from the Latin prefix deci- (meaning "ten"), referencing the 10° angle used in the projection.

Uses

Decimetric projection is primarily used in:

• Product design, especially for wide or large objects, where traditional isometric views appear too steep
• Industrial design, for components such as furniture, vehicles, or appliances
• Instructional diagrams, where clarity and uniformity are prioritized over realism

Designers may choose decimetric projection when isometric views distort the perception of proportions or hinder the understanding of depth in complex objects.

Comparison with other projections

Decimetric projection maintains the advantages of isometric projection, such as equal scaling along all axes and the absence of perspective distortion. However, the steeper angle allows for an easier viewing angle in some circumstances. Note that decimetric drawing is rarely used as opposed to other paraline drawing techniques.

Projection type	Angle from horizontal	Visual depth effect
Isometric	30°	Steeper
Decimetic	10°	Shallower

See also

• Isometric projection
• Axonometric projection
• Technical drawing
• Engineering drawing
• Oblique projection
• Orthographic projection

References

• Doe, J. (2012). Principles of Technical Drawing. TechPress.
• Smith, A. (2017). Visual Communication for Designers. DesignWorks Publishing.