Swift solutions

As mid-range CAD software matures, the hardware is beginning to take much more of the tedium and the hard work out of the design process, letting designers get on with their job rather than having to become software experts.

The Windows interface revolutionised the universal appeal of CAD/CAM technology, but like every evolution of tried-and-trusted software much of the underlying technology stayed the same.

With SolidWorks 2007 due to be announced this month, SolidWorks is set to move up a gear in the innovation stakes. The software features SWIFT (SolidWorks Intelligent Feature Technology) a knowledge-based, adviser-style technology more reminiscent of the larger enterprise CAD systems of old.

'Solid modelling is a very lonely place when things don't work out as planned,' said Nick Ballard, of UK hi-tech market research and business consultant Cambashi. 'What this technology does is guide users through tricky operations so that error-free models are produced in a much more effective and efficient way manner.'

Jon Hirschtick, the co-founder of SolidWorks, was keen to take the mystery out of modelling operations and encourage the computer to do all the hard work. SWIFT is starting to realise this ambition.

'The idea behind SWIFT is to go back to basics and examine ways to improve the user experience of 3D CAD by improving the things that people use every day,' said Ballard. 'In SolidWorks and any feature-based parametric solid modelling system there are some things that even experts find quite difficult — particularly when things go wrong or the interpretation by the CAD system of your design intent is not the same as you thought it would be. Some of the errors produced by 3D systems are not that intuitive and they can cause more consternation than information.'

SWIFT in SolidWorks 2007 comes in the guise of FeatureXpert, SketchXpert, MateXpert and DimXpert.

FeatureXpert has been initially implemented for filleting and drafting operations. If you try to fillet a part and the fillet fails, most systems just inform you of the failure. FeatureXpert, on the other hand, analyses the problem and presents you with several alternatives to correct the failure.

You click through the alternatives and choose most suitable one — even if that is a compromise on your original design intent it is far better than staring at a failed fillet and wondering what to do next.

In the hands of an expert, filleting is a fairly painless process, but it might take three or four operations — in the right sequence — to deal totally with one part. At a very basic level with SolidWorks 2007, you can specify the filleting as one operation and use FeatureXpert to unscramble any that have been applied in the wrong order or use inappropriate sizes. As part of its process, the program will look at a variety of different ways of achieving the required filleting regime and present you with a semi-automatic optimised solution.

Of course, if certain fillets are geometrically impossible FeatureXpert will not achieve the impossible — but it will present solutions that are very close to what is required. The program, which uses only standard fillet features to achieve the result, does not substitute complex surfaces, variable or set-back fillets.

With drafts too, experts will apply these prior to filleting. If you didn't and attempted to apply draft after all filleting was complete, the chances are that there would be a failure somewhere. FeatureXpert automatically decides where draft features need to be included in the sequence to produce the desired result and allows you to move them appropriately.

SketchXpert works in a similar way. Often, when relationships and dimensions are applied to sketches it is all too easy to get into a situation which makes the sketch over defined.

In the past, the only way to fix this condition was to manually go back and delete or change the dimensions and/or relationships until the sketch was fully defined. SketchXpert, like FeatureXpert, diagnoses the problem and presents a range of alternatives for fixing it. As you toggle through the proposals you get graphical feedback, illustrating what the system is suggesting.

MateXpert is conceptually the same kind of utility in the assembly environment. In situations where conflicting mating operations are applied, the program sorts it out. Again you get graphical feedback where the system shows you the mates that are contributing to the problem, and it allows you to toggle through solutions to achieve the desired result.

DimXpert is also a productivity tool, including expertise in dimensioning manufacturing features. Sometimes in the drawing environment the manufacturing intent is different from the design intent — most users don't just bring the model dimensions through into the drafting environment.

Generally many of the dimensions for manufacturing a part are applied manually. DimXpert recognises things — such as patterns of holes — and it will dimension holes and slots in a logical way for manufacture. For patterning holes if you dimension one hole the program will recognise the pattern and dimension the rest.

The power of parametric solid modelling is its ability to capture design intent, something that 2D CAD cannot do. Capturing it helps users manage change in a design database and ensure that components assemble correctly. Often the price of this power has has meant that users have been forced to learn myriad 3D modelling rules, special techniques and workarounds.

SWIFT technology resolves this power-complexity paradox. It has mastered 3D CAD's most frustrating details on behalf of the user, whether novice or expert. This allows them to focus on what they want to accomplish, rather than the rules of 3D CAD software. SWIFT powers a series of expert tools that diagnose and cure problems in feature order, mates, sketch relationships, tolerance application, and other similar operations.

This kind of technology will eventually permeate the whole system so that all complex CAD operations will be made easier to analyse and diagnose.

The Cosmos analysis tool that comes bundled with SolidWorks Office Premium is also benefiting from this kind of approach and with every successive release it is easier to use by the general-purpose design engineer rather than the stress analyst — so we should look forward to more of the same next year.

So with SolidWorks leading the way, it can surely only be a matter of time before such all-encompassing programs become the norm.