Isometric Ambiguity - Thumbnail

Here is just one simple isometric drawing; a good example of isometric ambiguity.

The drawing is an example of how one can resolve the ambiguity of a "pure" (black-lines-on-grid only) isometric drawing, using shading techiques. However this does not actually work, even in this simple case. In fact this figure is a well-known example of an optical illusion. Even with shading it can be interpreted in two ways, so the "pure" or canonical representation can represent (at least) 4 different physical objects.

You may think that you see and understand the drawing, seeing it "the right way", clearly and for certain (it's fairly common for people to feel this way about their own interpretation/visualization/conception). You may figure, with the right tools and materials you could make it. But another viewer/interpreter can easily see it a second way, that is materially different. Given only the isometric drawing - with no other documentation, drawing, communication, nor shared understanding - there is no way to resolve this ambiguity, which can result in useless parts being manufactured, wasted money, delays, and failed projects. Not to mention arguments that can never be authoritatively settled and degenerate into table-pounding, recriminations, and failed business relationships.

What to do about it and how

Artists can use the isometric grid to explore - and exploit - the creative possibilities of isometric ambiguity. This is a process of trial and error, searching for and coming up with combinations of cubes and other figures that look visually interesting.

Non-artists, however, need to keep in mind that despite the advantages of isometric drawing, the well-known problem of "isometric ambiguity" can never be resolved, without augmentation of some sort. Shading the drawings is a half-step which as briefly shown here, doesn't even work; plus it creates its own problems (such as incompatibilities between different storage and representation systems) not inherent in pure/canonical isometric drawings.

To safely and adequately (definitively) represent 3-dimensional objects in/on a 2-dimensional drawing therefore requires using multiple graphical - and other communication - techniques. Architects rely on plans, elevations, artist's sketches/representations, perspective drawings, and in many cases (such as oil refineries), actual 3-dimensional models. Engineers use their own sets of tools and conventions; different but (hopefully) accomplishing the same goal. And of course nowadays computerized solid-modeling allows effective storage, representation, and communication.