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TecPlot's no square

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It's some while since I last looked at TecPlot - more than two years, in fact, at release 9. A lot has happened in the time between. Version 10 will have come to market by the time readers see this article, though as I finalise it I have seen only as far as the final release candidate beta. It has been a different sort of ride from last time: Amtec (TecPlot's publisher) now keeps a very tight rein on beta access, with each version expiring just as its successor is issued, which made it impossible to risk the success or failure of a live project on the software. However, I've been able to build a good knowledge of the product by dipping it into work in progress as I worked up through the development phases.

TecPlot is a visualisation package, able to cope with extremely bulky data sets across multiple grid structures, without the usual requirement that they be referenced in rectangular terms. Scientific data, particularly those sampled to the mesh layout of a FEM (Finite Element Method) model, are frequently referenced to bases that reflect the problem or its computational requirements rather than the needs of engineers or mathematicians. TecPlot accepts data in these non-rectangular forms, using software 'loaders' which interpret data according to supplied conventions.

A subset (top right) of the hoverfly data is being probed point by point with the mouse cursor; the spreadsheet indicates by highlight the closest cell to the point currently being probed. The bottom of the frame displays information on the TecPlot zone style. Click on the image to see a larger version in a new window

Data set size is also increasing. FEM models, once again, are notable here, routinely generating multi-gigabyte datasets containing measurements of numerous variables over many millions of points at high sampling resolutions. Data bulk problems are compounded by requirements for post-processing, particularly in fluid flow situations, before multi-dimensional data can be visualised. To display data from Particle Image Velocimetry systems in a visually understandable form, for instance, requires vector plots, ribbons, or stream lines.

TecPlot, then, sets out to visualise immense datasets, on non-standard reference systems, with rendering, hidden surface and hidden line removal, zooming and rotation, all manipulable in real time. It sets up linkages between data and plot objects in diverse ways, emphasising intuitively interpretable sensory analogues that can be learned, internalised, and instinctively read. Plots contain coherent compound visual data structures ('field plot objects') which each have a high degree of autonomy - you can, in effect, set up multiple diverse graphics plots, but superimposed into the same display space. Set up a plot of object positions and their sizes, for example; then set up a plot of fluid flow and another of cross-sectional contoured temperature slices; but set all three up in the same frame, so that the relation of flow to objects and changing temperature is visually explicit. The user interface is page-oriented - the program envisages use of its final artefacts in reports, and so on.

In this new release, developments in the user interface are first noticeable. Modeless dialogues, whose appearance used to be irritating in a minor way, have been tamed; you can now specify where you want them to pop up. The 'view' and 'axis' menus have been extended, gaining in each case a section which reflects the plot type currently in use, and there is an optional new dialogue from which to specify the initial plot type and zones to be plotted. The progress indicator is no longer a distracting and obstructing dialogue but a discrete progress bar out of the way on the status line. More significant, the spreadsheet highlights for you the cell nearest to correspondence with your current location. Multiple 'undo' levels are a welcome arrival for anyone who makes frequent mistakes or prefers (like me) to 'suck it and see'. Macros now have a 'drop and go' viewer, which can be transferred across platforms, and have seen their scope significantly enhanced by addition of an Else/ElseIf structure, They are now accessible from keyboard short cuts. Work is speeded up, in the initial phases particularly, by new defaults. It's also become easier and quicker to standardise or alter dominant design elements. Also contributing to more streamlined working are a collection of quaintly named 'nice' options which deserve more respect than that label invites: keyboard short cuts which modify current or full-size views, according to preset visual layout assumptions.

This improvement on the user interface is reflected in enhanced options, which provide a richer data/visualisation interface as well. One of these is the option to link RGB mixes to data values - each colour component in each plot object being controlled from an assigned variable, or assigning only two colours with one of them being calculated. This data colouring dramatically increases the potential for rapidly and intuitively understood content. Working alongside this are continuous colour flooding and a new facility for triangulating polylines for highly flexible zoning, and a number of expansions of detail such as an expanded range of 3D scatter symbols and specular highlight control. The picture is completed by the ability to set up as many as four separate groups of contour controls, each with its own independent library of attributes - each plot object within the display can be pointed at a set of contouring criteria appropriate to its purpose. Contours have also gained an autospacing dimension, referred to (as with the screen layout above) as 'nice'. A number of settings (the positions of slices, iso-surfaces, x and y axes, for instance) can be linked across frames (TecPlot's top level of organisation) with a button click, making it easier to maintain visual correspondence between them and thus reduce perceptual noise. Echoing this comes an ability to link key line settings within the frame itself. In the same spirit of spreading interconnection, variables and node-maps can now be shared between zones.

There are also structural changes, which, quite apart from present impact on manner of use, point to probable future development. TecPlot formerly had four frame modes, reflecting the plot types; these have been replaced by a more general structure within which the number of envisaged plot types is arbitrary. New in this release is the 'auxiliary data' structure, which allows assignment, retrieval, copying, display, and saving with the data file of information about the project in hand. This is another development that simplifies (and so encourages) consistency management. Also in this same general direction is the data journal - a linked macro list, which can (optionally) be saved with the dataset. The journal is a valuable 'window' onto the developmental progress of a project, encouraging documentation and audit trail documentation.

TecPlot's ability to accept data in non-rectangular form depends upon software 'loaders' which interpret data according to supplied conventions. There are 10 of these loaders including, for instance, an 'Excel loader', 'Gridgen loader', 'general text loader', and so on. Relative paths are now supported for these, and data can now be appended. Continuing the I/O theme, export of frames (singly or collectively, and now on or off screen) to common graphics formats, including AVI, is joined by import of BMP or PNG files as geometries.

I have found one minus point: an exasperating tendency for the whole program to fall over and close on import from certain complex Excel sheets. I have not been able discern a pattern; most sheets are OK.

However, in general, TecPlot has moved very substantially forward, in the detailed evolution of a mature environment that works better, more smoothly, more responsively and more effectively.

TecPlot RS

I had hoped, when I started, to review both TecPlot 10 and TecPlot RS against a more general application and corporate backdrop; unfortunately, Amtec vetoed the idea. This is a pity because TecPlot RS is an interesting extension of TecPlot's philosophy and capacity into a very specific field, and the comparison is illuminating. A review of TecPlot would, nevertheless, be incomplete without some mention of RS, so I briefly tried a trial download and was allowed to observe a live installation at work.

RS is a tool tailored from TecPlot cloth specifically for users concerned with oil reservoir dynamics. The flow within these reservoirs is modelled, using multiple disparate data sources, within a single exploratory analysis environment. Measurable variables derive from attributes observable (or modellable) over surface space. Images of the reservoir as a whole, or transects through it, have to derive from simulation. The combined measured and simulated data always run to the very large sets that TecPlot is well equipped to handle.

The whole of TecPlot's capability is available to the RS user, but with extensions and adjustments to emphasise and facilitate those aspects that most concern the products market sector. In the installation that I observed, animations were heavily used. Some would 'cruise through' a reservoir (rather as if in a submersible, if one were capable of navigating such a voyage), both in space and forwards or backwards in time. Others offered journeys down through successive geological layers, observing the two dimensional relation and interaction of different wells to each other and to potential future circumstances. Then there were those which represented the reservoir (with associated wells and so on) as a solid within a transparent fluid - allowing the viewer to cruise around it, observing its topography from outside.

All in all, RS is an impressive illustration of how the core facilities of TecPlot can be applied and extended to a dedicated field, when the demand is there.