When is a photograph not a photograph? When it is a super realistic computer rendering. Stephen Holmes contacted some of the biggest names in photorealistic rendering to get their views on why more of us are turning to 3D CAD designers to create that perfect picture.

Glancing through a glossy magazine, or browsing the web we may all suspect some image trickery has taken place. A doctored image here, an airbrushed model there; we're accustomed to how adept modern media has become in deceiving the eye. Yet there are still occasions when the gap between reality and rendered is more difficult to judge.

By definition, a photorealistic image is created by simulating the physics of light in a mathematically modelled scene, the goal being to create images indistinguishable from photographs of the real world. This provides benefits across a wide range of industries, from the design of an object right through to the advertising used to sell it to us.

Kate Marshall, marketing manager of ARTVPS, the UK rendering solutions firm and producer of Mental Ray software, sees the long term value of design data increasing thanks to the progression of photorealistic 3D visualisation: 'It allows not only designers and modellers, but all areas of a business to maximise the investment made in the design stage, through the aid of photorealistic rendering. Marketing departments have woken up to the idea that product photography can be produced totally convincingly from 3D data using photorealistic rendering techniques.'

Marshall continued: 'The creation of a physically accurate, virtual prototype has numerous benefits for different areas within a business. In the design stages, virtual photography enables manufacturers to see how the finished article will look in a 'real' environment and make informed decisions. Consumer testing can also be undertaken and styling changes made. However, it is as the product goes to market that the real benefits of virtual photography can be reaped.'

Thomas Teger, marketing manager for US rendering giant, Bunkspeed, views a largely reduced dependency on physical prototypes and an increase in accurate lighting conditions as repurposing design and engineering data for the sector of sales and marketing. 'Delivering ultimate flexibility when it comes to colour, finish and location of the product, offers dramatic cost savings, while increasing flexibility and overall quality,' explained Teger.

Liam Stacy, managing director of Maxon Computer, makers of Cinema 4D, believes that it is an indispensible tool for engineers: 'The average person has difficulty in imagining what a design on the drawing board will look like when it's actually built. With photorealistic rendering, you can overcome that problem and show exactly how it could look. It brings the product to life and gets people much more enthusiastic about the product - providing it's a great product, of course!' 'Our customers are also telling us that the photorealistic renderings are helping to refine designs. If the viewer can really see how the product looks, it's easier for them to give feedback on what they like and don't like. You can show the product in a variety of different materials, and test which one looks best, without having to build expensive, time-consuming prototypes.'

Cost seems to have been the main reason behind the dramatic uptake of photorealistic imaging across new fields. Asked where this type of rendering is taking place more commonly now, Stacy said that it's everywhere we look: 'Architecture, product visualisation, illustration, engineering, broadcast, point of sale. Several years ago machines that could achieve photorealistic renders were too expensive for these types of companies, so they had to make do with basic-looking renders. That's no longer the case.'

The decrease in the price of improved hardware, with more power and cores available on the CPU, as well as the abundance of graphics card technology, has seen ray tracing for rendering become much faster, allowing software to take advantage and become more accessible.

'Recent years have seen massive jumps in processor speed, but more importantly the cost of processors and other components, such as RAM, has fallen sharply in price too,' added Stacy. 'Gone are the days when serious processor power cost tens of thousands of pounds. Now pretty much anyone can get their hands on a PC or Mac capable of churning out complicated photorealistic renders without having to wait weeks for the results.'

'Maxon was one of the first software developers using multi-threaded code, speeding up rendering by almost twice or more using multiple processors or processor cores in one computer. We have more than 10 years of experience in creating multi-threaded applications and are looking forward to future developments in the multi-core architecture of CPUs. Intel has recently presented an experimental chip with 80 cores, so the times coming will be very interesting. When you think about 80 cores, it hits you that there is only so much software can do.'

As a result, many examples of photorealistic rendering software now have the capabilities for instant visual results. Bunkspeed's HyperShot software, for example, takes advantage of this. 'You instantly see what you are getting, the moment you drop the material onto the object and move or change the lighting. And since HyperShot is build on a multi-threaded architecture that is highly optimised for multi-core and multi-CPU systems, performance increases linearly as more cores/CPUs are being added,' extolled Teger, adding with firm conviction: 'As far as Bunkspeed is concerned, it's a case of 'bring on the CPUs / cores', the more the merrier!'

Photorealism is more than just activating the light around a 3D object, selecting the right techniques and tools can be a complicated business when trying to capture the authentic nature of a scene. Not only does a designer have to create the natural effects, shading and light, but a lot of what makes the best images stand out - what, in effect, makes them believable - is the mimicry of 'capturing' the image through a lens. The time and training previously needed to learn these effects and how to manipulate an image is reducing in time with the growing intuition of software. 'The biggest benefit,' insisted Teger, 'is that it puts digital image creation with photographic quality into the hands of literally everyone and anyone involved with 3D digital content. This opens up a huge market and also develops new markets, as it now allows people to interact with 3D digital data who have never touched a 3D authoring system before.'

Maxon believe that ease of use has been key to the rising profile of photorealistic rendering and that further growth in the market will stem from similar software assistance. 'Ease of use is always at the heart of CINEMA 4D developments,' confirmed Stacy, but added: 'It still takes a while to set up your scene for realistic lighting and textures. Most software manufacturers have solutions for achieving many things in 3D. Now the technology is in place, the next goal is to refine it and make it easier. That's what we strive to do. Our heart of development is always in making professional 3D easier.'

Similarly, Bunkspeed is working on a new user interface in the new version of HyperShot, as well as adding a 'button' inside current CAD applications for better integration. 'This will launch HyperShot from within the CAD application while keeping it completely separate from the CAD application itself, pushing the geometry and camera information directly into HyperShot. When an update of the design occurs, all the user need to do is push the geometry back into HyperShot, without the need of repainting the model,' explained Teger, adding that improved speed will arrive with the optimisation of hardware, expecting rendering times and overall performance to increase linearly as core/CPUs multiply.

Simple techniques and tools to add more realism through the software are fundamental for growth, according to Kate Marshall: 'We need better interactive tools to let designers work with real lights, real materials and real cameras. Whilst the presentation of raw algorithms and mathematics to users works ok in the elite world of movie special effects production, where software experts are employed on every shot, simpler and more intuitive interfaces need to be developed for design professionals who aren't rendering experts.'

To further advance the technology available, Marshall believes there is a real need for interactive rendering solutions, which give the users and clients better and faster control over complex photorealistic images, and a much greater integration between 3D rendering and 2D post processing.

Future growth will rely on the next generation of graphics processors to allow for the advancement of software. Bringing a product to life on the drawing board through animation to provide designers with more options and variables is the next big thing, but will rely on the availability of more powerful hardware to support the software. Now that other industries have made the discovery of photorealistic rendering it seems that there is a good chance this will come sooner rather than later, as emphasis is already being placed on improvement.

'The expense that accompanies the launch of a new product, particularly within the automotive sector, often runs in to millions. The cost of creating physical prototypes to be photographed for advertising and marketing material is just the tip of the iceberg,' Marshall enthused. 'Virtual photography removes the need to ship expensive and potentially sensitive prototypes around the world for locations shoots. It easily allows last minute alterations to a prototype or localised product differences to be made, without affecting budget or tight schedules.'

'3D virtual photography also enables businesses to prepare and produce marketing collateral in advance of a finished product leaving the factory. Brochures, adverts, billboard posters, website content or even animations can be developed from the original 3D model,' she concluded.

The savings made to other industries are mammoth, creating demand for the skills and technologies of photorealistic 3D design through all stages of production, development, marketing and sales, something that should keep photorealistic rendering in the picture for a long time to come.