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IRIS Explorer - what's new in Release 3.5?

The new version of IRIS Explorer, the leading visualisation toolkit from NAG, is Release 3.5. This contains many internal enhancements and a large number of new and improved modules, many of which are based on other NAG products such as the well-known NAG Numerical Library and the NAG Graphics Library.

The major internal enhancement is the updating of the underlying version of Open Inventor to 2.1. IRIS Explorer is built on top of Open Inventor, the object-oriented, OpenGL-based 3D toolkit from Silicon Graphics, which makes it a natural authoring tool for scenes in Open Inventor (in fact, the IRIS Explorer geometry data type is an Inventor scene graph) or VRML, the Inventor-based language for 3D on the World Wide Web. Open Inventor 2.1 is a performance release, with rendering speedups of between 20% and 400%, and IRIS Explorer 3.5 reflects these enhancements in its Inventor-based modules such as Render. In addition, it incorporates all of the other improvements in Open Inventor 2.1, such as full VRML support, a new locate highlighting node and a new all-in-one geometry manipulator. Finally, the Render module has been completely rewritten for this release to incorporate new features such as 3D cut and paste, improved scene picking, editing and saving and software rendering via X. This latter option means that IRIS Explorer can now run on any display, even those that do not support OpenGL. Other internal enhancements include the incorporation of NAG Library interpolation routines into the system library. The NAG routines use a state-of-the-art algorithm, which results in faster, more accurate interpolation for all modules that make use of this facility.

Features that have been added at 3.5 include new pyramid modules for the display and analysis of data on irregular grids and non-vertex data (such as, for example, finite element datasets). Geometry can now be coloured according to data associated with edges, faces or cells, and new modules have been added for creating contours, displacement maps or streamlines from irregular datasets. New modules for the display of multivariate data and the analysis of vector fields using novel visualisation techniques such as line integral convolution and vector smoke have also been added.

Besides adding new modules, new functionality has been incorporated into existing modules. For example, the popular LatToGeom module can be used to produce a sheet from a 2D lattice which is coloured according to the data values of another 2D lattice. In older versions of IRIS Explorer, this colouring was done on a per-vertex basis, with the colours being smoothly interpolated between points on the surface. This functionality has been complemented in Release 3.5 with the option for solid contouring on the surface, which can be used to rather striking effect. In a similar way, the IsosurfaceLat module, which can produce an isosurface through a 3D lattice coloured according to the local value of another 3D lattice, now features solid contouring in Release 3.5.

IRIS Explorer 3.5 includes a number of enhancements for annotation of the rendered scene. Thus, for example, the DrawText module, which was introduced at Release 3.0, now supports inline font changes, subscripting and superscripting of text and multiline fractions, in addition to existing features like embedded parameter values in the text, support for multiple lines of text, and control over colour and placement of text. A new module, NAGText, incorporates all of the enhancements to DrawText, plus further support for typesetting of mathematics in annotation labels. Finally, the Annotation module has been rewritten to incorporate multiple labels, each with their own font, size and colour, and lines and arrows for pointing at objects in the scene. Support for the editing of annotation elements has been improved and expanded.

The popular NAG Graphics modules which appeared at Release 3.0 have been updated to support geometry output. This means that in Release 3.5 it is now possible to construct composite displays of 1D, 2D and 3D data in the window of the Render module. In addition, the NAG Graphics modules continue to support vector PostScript output. Other modules such as TransformGeom and LineEdit have also been added, which allow the user to edit attributes of the geometry such as location and linestyle. NAG have just released IRIS Explorer 3.5 for Silicon Graphics and will shortly be announcing other ports (for both UNIX and Windows NT platforms) of this powerful visualisation system and application builder. In the meantime, keep checking out the Web page of the IRIS Explorer ( for up-to-date announcements and further information about IRIS Explorer.

Jeremy Walton
NAG Limited