The 3D Projection

The 3-D Projection is a projection technology used to turn  objects, into a 3D display on a surface for video projection. These objects may be complex industrial landscapes, such as buildings. With the use of modern technology three-dimensional object is spatially mapped onto the virtual program which mimics the real environment it is to be projected on. The software can interact with a projector to fit any desired image onto the surface of that object, this technique is used by artists and advertisers alike who can add the following to enhance their products: 

• Add extra dimensions, 
• Optical illusions, 
• Notions of movement onto static objects. 

The video is commonly combined with, or triggered by, audio to create an audio-visual narrative

History

Although the term projection mapping is relatively new, the technique dates back to the late 1960s, where it was referred to as video mapping, special augmented reality, or shader lamps  One of the first public displays of projections onto 3D objects was debuted in 1969, when Disneyland opened their Haunted Mansion ride. The ride used fake disembodied heads as objects which had 16mm film projected onto them to make them appear animated. 

The next record of projection mapping is from 1980, when installation artist Michael Naimark filmed people interacting with objects in a living room and then projected it in the room, creating illusions as if the people interacting with the objects were really there. 

The first time the concept of projection mapping was investigated academically was at the University of North Carolina at Chapel Hill in the late 1990s, where scholars worked on a project called Office of the Future to connect offices from different locations by projecting people into the office space as if they were really there. By 2001, more artists began using projection mapping in artwork, and groups such as Microsoft began experimenting with it as a means of technological advancement

 

Orthographic Projection

When the human eye looks at a scene, objects that are at a distance appear smaller than objects placed near by. Orthographic projection ignores this effect to allow the creation of to-scale drawings for construction and engineering. These projections are a small set of transforms often used to show profile, detail or precise measurements of a three dimensional object. Common names for orthographic projections include plane, cross-section, bird's-eye, and elevation.

If the object is placed at a viewing plane which is parallel to one of the primary axes which are the x, y, and z axis, these axes are mathematical transformed to project the 3D point onto the 2D point. While orthographically projected images represent the three dimensional nature of the object projected, they do not represent the object as it would be recorded photographically or perceived by a viewer observing it directly. In particular, parallel lengths at all points in an orthographically projected image are of the same scale regardless of whether they are far away or near to the virtual viewer. As a result, lengths near to the viewer are not foreshortened as they would be in a perspective projection.

 

Weak Perspective Projection

A weak perspective projection uses the same principles of an orthographic projection, but requires the scaling factor to be specified, thus ensuring that closer objects appear bigger in the projection, and vice-versa. It can be seen as a hybrid between an orthographic and a perspective projection, and described either as a perspective projection with individual point depths replaced by an average constant depth . or simply as an orthographic projection plus a scaling.

The weak-perspective model thus approximates perspective projection while using a simpler model, similar to the pure (unsealed) orthographic perspective. It is a reasonable approximation when the depth of the object along the line of sight is small compared to the distance from the camera, and the field of view is small. With these conditions, it can be assumed that all points on a 3D object are at the same distance from the camera without significant errors in the projection

Perspective Projection

As mentioned earlier that when the human eye views a scene, objects placed at a distance appear smaller than those that are placed close by, this is known as perspective. While orthographic projection ignores this effect to allow accurate measurements, perspective definition shows distant objects as smaller to provide additional realism.

The perspective projection requires a more involved definition as compared to orthographic projections. A conceptual aid to understanding the mechanics of this projection is to imagine the 2D projection as though the object(s) are being viewed through a camera viewfinder. The camera's position, orientation, and field of view control the behavior of the projection transformation. The following variables are defined to describe this transformation:

Use of 3D Projection

Artists may use it as an avant-garde form of expression as it is a new technology that can turn their creative ideas into 3D projections, connecting them with their audiences in a new way. Video projections have appeared in urban centers such as New York City and London, where artists have used guerilla projections in public without any necessary approval. This way, artists can show their work in any location as, anything and anywhere can be a canvas. Often people also use it as a means of activism; the group Occupy Wall Street has used it to project onto the Verizon Wireless building in New York City as a means to visually spread the word that Occupy Wall Street is still alive.