Perspective Model

A Perspective Model is a structured physical, graphical, mathematical or computational representation of a spatial reality or of a perspective system. As a Perspective Product, a model provides an organised representation through which spatial form, relationships, processes or appearances can be examined, reproduced, calculated or explored.

A perspective model may represent the spatial object or scene itself, or it may represent the perspective system through which that object or scene is viewed, imaged, measured, projected or represented.

Model as a Perspective Product

The Product level asks what a perspective process produces. One possible result is a model: a structured substitute, reconstruction or representation of some aspect of a spatial object, scene or perspective system.

The model may itself be the principal outcome, or it may provide the underlying structure from which further views, images, measurements and calculations are generated.

Models of Spatial Reality

A perspective model may provide a three-dimensional representation of a spatial object or scene. The model can preserve selected information concerning form, structure, scale, proportion, position and spatial arrangement while simplifying or reorganising other properties.

The model may be physical or virtual. It may exist at life size, at reduced or enlarged scale, or within a computer-generated coordinate space.

Physical Perspective Models

A physical model is a three-dimensional material representation of a spatial object or scene. Architectural models, scaled objects, experimental spatial constructions and other physical reconstructions can establish perspective relationships that are subsequently viewed from different positions and directions.

Because the model itself occupies physical space, it can produce different perspective views as the observer or camera moves around it.

Virtual and Computer Perspective Models

A virtual perspective model is a computer-generated representation of the form and structure of a spatial reality. Such a model may also incorporate material, optical and mathematical properties so that different perspective images and views can be generated from within the model.

Computer models can support multiple viewpoints, scales and times. A single model may therefore generate many different perspective views while maintaining a coordinated underlying spatial structure.

Examples include systems used in CAD, CGI, computer vision, GIS, virtual reality and augmented reality.

Models of Perspective Systems

A Perspective Model need not represent only an external object or scene. It may instead represent the perspective system itself.

A graphical or mathematical model can describe relationships among such elements as viewpoint, viewing direction, spatial object, picture or image plane, projection geometry and resulting image.

Such models can be used for viewing, matching, representing, analysing or constructing perspective relationships.

Optical, Graphical and Mathematical Modelling

Optical modelling uses real physical optics or modelled optical principles to form or analyse a perspective image or view.
Graphical modelling uses graphical methods to construct an artificial representation or perspective image of a spatial object or scene.
Mathematical modelling uses mathematical or geometrical methods to define and calculate relationships between spatial reality and its perspective representation.

These modes can operate independently or together within a larger perspective system.

Model, Representation, Image and View

View emphasises how something appears from a particular viewpoint.
Image emphasises a visual result that has been formed, captured, projected, displayed or generated.
Representation emphasises something that depicts or stands for spatial reality.
Model emphasises a structured representation through which spatial form, relationships or processes can be organised, analysed or reproduced.

A computer-generated architectural model, for example, can be a Model of a building, generate many Views, produce rendered Images and function as a Representation of a proposed spatial reality.

Perspective Model and Modelled Form

Perspective Model should not be confused with Modelled Form.

A Perspective Model is considered here at the Product level: it is a model produced, constructed or used as the outcome of a perspective process.

Modelled Form, by contrast, belongs to the analysis of Form. It is the idealised or assumed geometrical Form used to analyse, describe, calculate or construct the relationship between Physical Form and Apparent Form.

Multi-View and Multi-Scale Models

One important property of a model is that it need not be restricted to a single perspective view. A sufficiently complete physical or digital model can support multiple viewing positions and directions.

Virtual models may additionally support multiple scales, changing times or interactive exploration. Different perspective images can then be generated from the same underlying model.

Examples of Perspective Models

a physical architectural scale model;
a three-dimensional computer model of a building or object;
a CAD model;
a CGI scene model;
a GIS model of spatial reality;
a virtual-reality environment;
an augmented-reality spatial model;
a geometrical model of a perspective projection system;
an optical model showing image formation;
a mathematical model relating viewpoint, object and image geometry.

Perspective Model Within the Analytical System

Within the PRC analytical framework, Model is treated here as a Perspective Product because it is something produced or constructed through a perspective process.

The same model can then be examined through the other analytical levels. Its source or mode concerns Category; its direction concerns Class; its method or system concerns Type; its resulting appearances concern Form; visible effects concern Phenomena; and what it does concerns Function.

The Product question is: what has the process produced? In this case, a model.