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Notes concerning Software Packages used in the Case Studies

Vistapro

Vistapro is a low cost, 3-D landscape visualisation programme. By combining artificial intelligence, chaos mathematics and user-defined variables, Vistapro simulates the visual characteristics of natural geology and vegetation upon topographic datasets. In addition, the package allows the user complete control over features such as lighting conditions and cloud cover which, taken together with its rendering capabilities, serves to breathe a semblance of life into the flatly coloured polygon worlds of traditional virtual reality. Vistapro can be used to render single frames or generate entire animation sequences as the observer moves through a landscape and, through the use of a companion programme called Vistamorph, can be used to animate changing lighting, geomorphological and vegetation effects over time.

As a result of this flexibility, Vistapro has become pivotal to much of our work, not only in producing still and animated visualisations of otherwise static, uniform datasets, but also in generating data for incorporation into other applications. An example of the latter is in the production of bitmap overlays to be draped over landscape models in programmes such as Truespace, or used in VRML worlds. This enables faster, smaller worlds to be produced by reducing the number of component polygons, whilst at the same time permitting the shadow detail inherent in the Vistapro-derived overlays, to communicate the full complexity of the original micro-topographic trends visible before generalisation.

The main limitation with Vistapro lies with its restricted data import capabilities. Vistapro can import its own proprietary DEM format along with that of the United States Geographic Survey (USGS). Although many applications can export USGS data, for example Arc/Info, the particular implementations of the standard utilised by the majority of commercial GIS utilities are unreadable by Vistapro. It is possible to import ASCII data files into the package but this usually entails some degree of macro programming, as in the case of Arc/Info, and the use of several intermediate applications.

Photomodeller

Photomodeller is a commercial utility that serves to produce 3-D models from groups of photographic images, and in so doing permits the rapid generation of highly accurate standing building surveys from photographic records alone. In practice several photographs of a given building are taken from a number of different camera angles and a number of common features, which can take the form of points, lines or polygons, are marked using Photomodeller. Through a process of interpolation these marks are then accurately converted into 3-D spatially referenced entities, which can be transferred directly to CAD, modelling or VRML generation packages.

Caligari Products

Most of the VRML we have produced has been constructed using a family of VRML modelling packages produced by the company Caligari. These comprise the initial product called Fountain, later renamed Pioneer, and its more feature- enhanced sister, Pioneer Pro. Due to the inevitable unreliability of the beta release versions of the above packages that were used in developing our approaches, a further member of the product family was also utilised. This comprised Truespace, a non-VRML but highly robust 3-D modelling and rendering package, most commonly used to generate high quality rendered single frames and animations. Truespace was often used to assist in the fine-tuning of the completed VRML models; however, with the full release versions of Pioneer now available this requirement is no longer necessary.

It should be noted, however, that Pioneer is a VRML browser in its own right and worlds produced solely within it may not function correctly within other browsers. As a result of this, it must be realised that when using Pioneer to construct worlds that are to be widely distributed, the resultant files may require some degree of manual editing before they can be released.

Land Survey System (LSS)

The Land Survey System is an excellent survey data processing workshop produced by the McCarthy-Taylor Partnership. It includes powerful TIN generation algorithms and its highly flexible design and data export capabilities makes it ideally suited to the peculiar requirements of archaeological landscape survey.

Paint Shop Pro

A good 2-D paint package is essential in all 3-D modelling exercises, and Paint Shop Pro is notable in that it is a cost-effective shareware package that met, and continues to meet, all of our growing requirements. Of particular utility is its ability to import and export the majority of raster, and some vector, graphics file formats.

Wcvt2Pov (version 2.6c)

This shareware 3-D file conversion programme can convert a wide range of 3D data formats, including AutoCAD, into VRML, but has no modelling capabilities. An improved version (2.7 beta) is currently available but only runs on Windows 95 and NT platforms.

A note regarding computer platforms

It should be noted that all of the packages mentioned here run under DOS or Windows 3.1 on a PC platform. This is due in part to the wide availability of relevant PC utilities and also to a desire to ensure that the approaches developed could be made available to the widest possible research audience, not simply those with unlimited access to UNIX-based visualisation engines. Similar packages, with the possible exception of Photomodeller, are no doubt available on other platforms such as the Mac.


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Last updated: Tue Sep 5 1996