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Let there be Lightscape

Want to see how a light fitting specified in your design works in a room? The upgraded Lightscape can help

Lightscape has long been recognised as one of the best rendering applications available. Its combination of radiosity and raytrace renderings produces images which are as close to real life as you get. Popular in the field of architectural rendering, it produces data on lighting levels within a scene as well as excellent rendered images, making it an especially ideal testing tool for lighting designers.

Version 3.2 is the first release since Lightscape software was bought by Autodesk and is the first upgrade for some time. Leading up to this release, there were a number of patch releases over the last year which improved overall performance. The new version, while not all that could be hoped for, does introduce a number of significant improvements.

Lightscape is a stand-alone application and works with most modelling applications; but Autodesk has worked hard to improve file compatibility with its own products over and above that of other manufacturers' software. Improvements have been made in file importation (including Autocad 2000 imports) and in inter-operability between 3D Studio viz and max. Geometry now comes into Lightscape much more cleanly; material attributes and orientation are preserved. It seems clear that Lightscape is being developed with the user of 3D Studio in mind. Autodesk has now dropped RadioRay, the radiosity plug-in developed for viz and max, and is offering registered users an upgrade path to Lightscape 3.2. Improved animation functionality will appeal to both traditional architectural users and the new breed of games developers who are discovering the benefits of Lightscape's rendering abilities. The interactive walk-through of radiosity solutions allows designers to explore their creations in almost real-time. As the radiosity algorithm produces a three dimensional database of lighting values for the scene, it does not have to recalculate when the camera is moved. This view-independence is a stark contrast to ray tracing and allows the models to be re-rendered very quickly. While the initial processing of a scene is very processor intensive, the re-rendering is more a function of your graphics sub-system. Open gl is fully supported in Lightscape and it is strongly recommended that you buy a fast Open gl card if you intend to make much use of it.

Keyframe animation is also supported by good controls over camera options. Spline-based camera and target paths can be used with full control over acceleration and velocity between frames. You should be able to import camera paths from max but we had some problems with this.

Lightscape is not a modelling application and is used in its simplest terms to import geometry, place lights within the scene, put materials on surfaces and then render this out. This said, libraries of common objects, complete with materials, are supplied with the application to allow you to 'dress' your scene. The usefulness of these depends very much on the type of project you are working on and the level of complexity you require but in the long run they can save you a great deal of time.

Libraries of materials and lights are also supplied on the cd, which is a godsend. Lightscape renders in a way that is as close to the real world as it can be and is therefore totally dependent on the quality of data it has to start with. Materials must be designed with real physically- based properties and lights. Anyone who has written a shader for Renderman will know how complex a job this can be. Fortunately users are provided with a series of templates for all the major material groups, glass, metal, plastic etc, which can be used as the basis for custom materials. These can then be mapped onto geometry using the standard range of mapping options. Version 3.2 offers much better material previews, making it a lot easier to produce convincing results. Procedural bump and intensity mapping also help when trying to fine the look of materials, as subtle changes to the relief and tone can be made.

The lights, like the materials, have to conform to physically-based standards to perform correctly. Colour and distribution of luminous intensity have to be carefully defined to produce the desired effect. With lighting, users are divided into two categories, those looking for the overall effect, for example games designers, and those looking to model the actual lighting conditions like architects. Depending on which category you fall into, creating your rendering can be either very straightforward or very complex.

Lights in the application behave as in the real world. Libraries of real light fittings are available as support for ies, cibse and ltli photometric formats, allowing manufacturers to provide test-based data on their products. Architects can place the actual fittings specified in the design and see how they perform. For example, in response to the complex legislation controlling lighting levels at various locations within a work place, the levels of light falling on a desk surface can be calculated accurately. Daylight levels can also be set to real times and physical locations to simulate any time of the day or year or hour, at any point on the planet. For most designers this will be the first time they have had a fast and visual method of testing their designs empirically.

The lighting-analysis tools provide information and average luminance values for both surface and work planes, and this information can be output as either a colour or greyscale Isolux image or as a series of point by point numerical values. This information could then be passed on to a lighting engineer.

While this scientific analysis gives away Lightscape's roots, it is perhaps now better known for the quality of images it produces. Radiosity is the main rendering engine within the application, providing a means to produce an excellent final image. This said, however, it has its limitations and raytracing is also needed to add specular reflections and highlights within a scene. If you had a mirror in a scene, for example, raytracing would be needed to produce the reflected image within it, while radiosity would account for the reflected light it transmitted to other surfaces. The rendering engine within Lightscape provides you with constant feedback as the images is continuously updated. Some radiosity solutions require the whole calculation to be carried out before an image is displayed which can take a considerable length of time. Lightscape continuously refines the images displaying the amount of available light that has been accounted for at the bottom of the rendering window. It soon becomes clear that once 90-95 per cent of the light is accounted for, the image improves very little. You are able to stop the process at any point which allows you to test ideas quickly without having to go through the whole lengthy process in full.

This release offers users free network-rendering via the Lsnet application now included in the box. This allows the distribution of rendering jobs across any available processors on a network. It also lets jobs be efficiently split across machines with multiple processors as it allows each one to become a separate radiosity-processing node. A dialogue box now provides a standard interface for monitoring and controlling rendering jobs, making organising work much more straightforward. The system can be used to schedule renderings so it is of use even if you are not on a network.

Once finished, images can be output in most of the standard formats including tif, tga, eps, bmp and jpeg. 24-bit or 48-bit images can be output at any resolution with the bonus of alpha channel support. This allows you to render images out which can easily be added into other images in Photoshop.

Full 360-degree panoramas can be created with built-in support for QuickTime vr or Realspace. Solutions can also be exported to max, viz or as vrml files for use on the Internet. A neat treat available within the application is the ability to save radiosity solutions as texture maps within a scene to greatly reduce the rendering time when using the interactive viewing mode. While the results do lose a little definition, the increase in speed more than compensates. A free viewing application is also provided to allow radiosity solution to be viewed by anyone. This is an excellent addition as it allows anyone to explore your scene. A useful addition to the suite of tools would be a web browser plug-in but we will have to wait a little while for this.

Version 3.2 maintain Light- scape's position as the number one rendering application for max and viz users. The alterations in this release go some way to making it easier to use but this is not an application to be taken lightly. If you are serious about your images and are prepared to put in some effort, Lightscape could well be for you. Given that it is based on a radiosity engine, it is best suited to interiors and scenes with complex lighting. Its ability to match real-world conditions, including natural lighting conditions, can produce images that are incredibly hard to tell from photographs. This could be the best £595 you've ever spent!

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