Design Nomenclature / Systems & Spec
Orthographic projection
Also called multiview projection, orthogonal projection, ortho view
Projection along parallel lines perpendicular to the picture plane, so faces parallel to that plane record true size and shape with no perspective convergence. The basis of the multiview drawing — front, top, side, arranged by convention — supplemented by section, detail, and exploded views where one face can't say enough.
In practice
Called “orthographic” in a 3D viewport to mean “not perspective”, which is true and misses the point: the value is measurability, not the look.
Not to be confused with
- AxonometricThe family of parallel projections showing three faces at once, sorted by how many axes share a scale: isometric shares all three, dimetric two, trimetric none. Isometric is a member of the family, not a synonym for it — this is the word you want whenever the angles aren't 30°.
- IsometricThe axonometric case in which all three axes meet the picture plane at equal angles — drawn at 30° from horizontal — so all three take the same scale and nothing foreshortens relative to anything else. That is why it can be measured directly, and why it reads as faintly wrong to the eye.