Projections: Orthographic

Orthographic projection (or orthogonal projection) is a means of representing a three-dimensional object in two dimensions. In technical drawing, a multiview orthographic projection is an illustration technique in which up to six pictures of an object are produced, with each projection plane parallel to one of the coordinate axes of the object. We use these kind of projection in our iCon collection of illustrations.

The views are positioned relative to each other according to either of two schemes: first-angle or third-angle projection. In each, the appearances of views may be thought of as being projected onto planes that form a 6-sided box around the object.

Consider an object enclosed in an imaginary glass box, positioned such that the panes of glass are parallel to the major surfaces of the object and at 90 degrees to each other.

If one “projects” lines from the corners of the object (with each line at 90 degrees to a surface of the glass), until these lines intersect the glass, one can lay out 6 “views,” each of which represents the object as it is “seen” by the various panes of glass.

Having projected the respective “views” of each face of the object onto the glass surfaces, we can “unfold” the glass box until all the “views” are laid out in the same plane as the “Front” view, giving the figure shown below. Notice that each view can “see” (and show) only one aspect of the object, and that all the views are aligned to one another, because of the “unfolding” of the imaginary box.

This process uses principles of orthographic (“true drawing”) projection. It also works in reverse: if you correctly draw the individual views onto the pieces of glass, fold them all up into a box with 90 degree corners, then project points from each drawing into the middle of the box, the resulting intersections will define the 3 dimensional object.

The advantage of this process is that it’s possible to apply a uniform system of co-ordinates (a “measurement grid”) to the pictures created in each view, and it’s possible to apply proportion ratios to these drawings – to “scale” them. It isn’t usually practical to make a drawing “actual size” – most objects are larger than most pieces of paper.

Views offereed from illustraStock:
We offererd that views in Low details (more iconic style) and Hight detail (more illustration style). Check our icon style guide.

Views offereed from illustraStock:

We offererd that views in Low details (more iconic style) and Hight detail (more illustration style). Check our icon style guide.

Front View

Is the one that shows the most features or characteristics. All other views are based on the orientation chosen for the front view. Also, all other views, except the rear view, are formed by rotating the lines of sight 90 degrees in an appropriate direction from the front view.

Other views not offered from illustraStock:

Right Side View

 

Shows what becomes the right side of the object once the position of the front view is established.

Back View

Shows what becomes the rear of the object once the front view is established. The rear view is at 90 degrees to the left side view and is a mirror image of the front view, except that hidden lines may be different.

Left Side View

Shows what becomes the left side of the object once the position of the front view is established. The left side view is a mirror image of the right side view, except that hidden lines may be different.

Top View

Shows what becomes the top of the object once the position of the front view is established

Bottom View

Shows what becomes the bottom of the object once the front view is established. The bottom view is a mirror image of the top view, except that hidden lines may be different.

 

Source: Orthographic Projection