Visualisation is key to enhanced success

Engineers continually demand more computing power for visualisation and analysis of designs. Tom Shelley reports on how one company is working to meet the challenges

Radical new developments in hardware and software will allow engineers to review designs in greater detail and perform more sophisticated analyses, developments that have been prompted by the demands of engineers, with regard to studying designs as a whole, in as realistic a simulated environment as possible. Capabilities for greatly enhanced computing power arise from this and the perceived need to perform analyses which will lead to optimum combinations and interaction of functional attributes.
Since David Hughes and Trimension pioneered the first Silicon Graphics (SGI) Reality Centre at Reading in 1994, the company has sold a further 592 of these room-sized immersive and semi-immersive systems. Major customers include the VW Group, which has 27, and the US Federal Government, which uses them for modelling and simulating all kinds of 'situations'.
Dr Eng Lim Goh, the company's chief technology officer, says: "Data sets are now growing faster than the affordable bandwidths available to move them. The method which currently interests us most is holographic data storage. (see Eureka October 2002 page17) We are talking big customer data sets exceeding 1Tb and Gigabit Ethernet becoming commonplace in the next one or two years."
On the software side, he tells us: "The next big field for Open GL is the application of occlusion culling (removing of parts of the CAD model which are not visible) in a major way. One has to do a fair amount of computing to establish what is in front of what." This is apparently not too difficult if the model data set remains fixed, but if the model is changed, such as the opening of a door, the data set has to be restructured, increasing the load.
"We will use cheap commodity graphic cards where available, but still intend to use them in an innovative way. They will, for example, all work on different parts of the memory. Stage one is organising the computing load distribution, and stage two balancing the load dynamically between different cards. At the present time, companies such as Rolls Royce talk about taking hours to visualise its datasets.
"If two or more systems access a large data set, they have to use a shared file system. Next year we will have up to 64 processors accessing a single memory, and we will then be able to link blocks of 64 processors together, using Red Hat Linux.
"When users want to visualise models with different components in different countries, we presently have to consolidate the model in one place. However, we are working on a storage area network which can span model components in different countries and are evaluating Sonet. Work on this began on 1 October.
"Datasets will continue to grow. Car companies want more and more detail. The USAF has published papers about vestibular stimulators which ensure that apparent motion perceived through human ear canals, is in synchronisation with motion perceived through the eyes, to reduce simulator motion sickness. NASA Ames is now simulating air traffic control centres at different airports to model various situations for training and testing." Dr Goh also mentioned the company's roll-up displays so that mobile users could also access data. When questioned by Eureka he confirmed that it was the developments by Plastic Logic (Eureka July 2002 cover story) which he had in mind, and that his closeness to Cambridge developments stemmed from the fact that he was a Cambridge man himself.
Brad Reddersen, SGI's senior vice president, visual systems and engineering said the company's customers want "better faster and cheaper". To provide this combination, the firm is developing two MIPS RISC processors per chip and two instructions per clock cycle, to quadruple performance for about the same price.
With regard to graphics, one major thrust is the development of scalable graphics systems in which the graphics processing task is distributed so as to work over multiple separate graphics 'pipes'. In these systems the graphics imagery is assembled into a single image using proprietary 'compositing' technology developed by SGI. There is also the possibility of using time-based compositing techniques in which certain elements of the computing system are processing the next image frame while the previous frame is still on the screen.
One other approach is the assignment of one processor for each part of the underlying model, or in the case of medical imaging systems, each organ. Medical is one of SGI's growing fields of business. As well as modelling the design of medical equipment, it is also possible to overlay images, obtained from MRI and other scans obtained in advance of surgery, onto organs being operated on, in real time. Such techniques are being pioneered in the UK by Manchester University working with Manchester Royal Infirmary.
Even heavier demands on computing power are put in place by those companies that feel the need to perform optimisation through undertaking multiple computing analyses. In Eureka's August 2000 issue, there was an account of how crash performance is optimised by varying different parameters. Now, according to Larry MacArthur, SGI's senior director of manufacturing marketing, the move is on to combine this with reduction of noise, vibration and harshness (NVH). The current practice of optimising one and then the other is liable to lead to a clash, since it is almost inevitable that the design which shows the best NVH behaviour is unlikely to show the best crash behaviour. The solution, called 'multidisciplinary design optimisation', requires the running of a large number of simulations to converge on a single final design.
Other issues which need to be addressed include design for manufacture and the growing movement towards 'Six Sigma': the process whereby manufacturing process variations are reduced to a point where the level of defects is no more than 3.4 per million parts. "No amount of whipping the work force will produce good products if the design is bad," insists MacArthur. And, if after all this, the senior vice president for marketing decides that the revised eye appearance of the vehicle is likely to result in poor sales, it is much better to decide this at the design stage, than when it reaches the prototype stage.
The design of cars is not a unique application. Toys, electronic products and even boxes of detergent in a retail setting are subjects of advanced modelling and visualisation. And while countries such as China may be regarded as lands of low-cost manufacture, business there is beginning to benefit from use of advanced CAD. If nothing else, exchanges of advanced CAD models with high quality visualisation allow Chinese subcontractors to see what is expected. Similarly, in the reverse direction, they allow the customers to see immediately whether the items the subcontractors are intending to supply are what was wanted and what was asked for.

Engineers, particularly those engaged in automotive and aerospace design, continue to demand increased computing power and better 3D graphics for improved visualisation

Suppliers are happy to provide this, and are devising ways to increase computing power four fold at a single stroke, with data storage and retrieval rates increased by even greater factors

Multi disciplinary design optimisation places a particularly heavy burden on computing power

Tom Shelley

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