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Graphical Projection in Graphic Design (to be continued)

Published on April 12th 2015

Graphical projection is an unpopular field in graphic design but I found extremely interesting. This post is dedicated to the dry background research. In the next few blog entries, let’s have a closer look on its application in contemporary visual design and how Graphical projection involved in my daily life as a humble designer for exhibition.

What is Graphical Projection?

There are plenty of definitions out there, let me put it in short and simple language: Projection is a protocol by which transform 3D objects on to a 2D surface.

I was introduced to projection during my high-school time in Vietnam. It was a part of a subject called Công Nghệ (Technology). I still remember I got caught cheating during a test, but it’s not a big deal because that was not the only time I got in trouble (lol)

That’s it! 3D to 2D, how simple. But the problems and the fun occur because no matter how accurate, we cannot transform 100% experience in 3D world on to a piece of paper. Every ethod has its pros and cons, and as the designer we should thoroughly understand them in order to make an accurate consideration.

Here’re some key terms to note:
View Plane/projection plane (PP): is identified with the plane of the monitor. If one takes a photograph of a 3D structure, the surface of the film is the image plane.



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Type of Graphical Projection:

There are 2 main categories. Perspective and Parallel projection.

Perspective projection: Centre of projection is at vanishing point
+ Size varies inversely with distance. Realistic-looking
– Actual distance and angles are not (in general) preserved
– Parallel lines do not remain parallel

Parallel projection: Centre of projection is at infinity
+ Good for exact measurement
+ Parallel lines remain parallel
– Actual angles are not preserved
– Less realistic looking

congnghe
This is me, sitting 8 hours is no joke. So i only wore comfortable clothes...pajama for instance!



Perspective projection

Donatello, Brunelleschi, and Da Vinci discovered this method during the Renaissance. Certain lines, which are supposed to be parallel, appear to meet at a point – which is called vanishing point.

Other way to explain is the View plane/ projection plane emanate from the center of projection (COP).

The number of principal vanishing points often classifies perspective drawings.

  • One-point perspective — simplest to draw
  • Two-point perspective — gives better impression of depth
  • Three-point perspective — most difficult to draw


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    Parallel projection

    In parallel projection, the lines of the object are parallel to their projections. Or we specify a direction of projection (DOP) instead of a COP

    There are two types:

  • Orthographic is a form of parallel projection, when projectors perpendicular to the view plan. As a result, the direction of projection is retained to the projection plane.

  • Multiple View is a kind of orthographic projection, which contains elevation view (front, side and rear projection of an object) and plane view (the top projection). The length and angle are accurately recorded, therefore it’s widely used in architecture and technical drawing

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    Axonometric

    is another form of orthographic projection, which shows many sides of the object in one projected image. The feature that distinguishes axonometric projection from Oblique projection is the inclined position of the object to the projection plane.

    When a surface or edge of the object is not parallel to the plane of projection, it appears foreshortened. When an angle is not parallel to the plane of projection, it appears either smaller or larger than the true angle.In parallel projection, the lines of the object are parallel to their projections. Or we specify a direction of projection (DOP) instead of a COP

  • Isometric projection : All angles are equal
  • Dimetric projection : Two angles are equal
  • Trimetric projection : None of angles are equal.
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    Oblique

    is a form of orthographic projection where projectors are not perpendicular to the view plane. But there is one side of the object inclined to the projection plane. Angles are changed depending on the kind of projection, while lengths are proportionally recorded.

    In Cavalier projection

  • DOP makes 45° angle with PP
  • Does not foreshorten lines perpendicular to PP


  • In Cabinet projection

  • DOP makes 63.4° angle with PP
  • Foreshortened lines perpendicular to PP by onehalf
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