3D CAD advances on all fronts

Tom Shelley looks at the strengths of three of the latest versions of leading CAD packages used in engineering

Tom Shelley looks at the strengths of three of the latest versions of leading CAD packages used in engineering

Each of the three leading 3D CAD package updates just announced, UGS NX3, Autodesk Inventor 9, and SolidWorks 2005 has its strengths for different types of user.

NX3 represents the final fusion of the UGS and SDRC product lines, and its embodiment is clearly aimed at the designers of large and complex products, and those that incorporate moulded shapes with complex curved surfaces.

Inventor 9 brings drawing and detailing facilities for those accustomed to working on 2D drawings into the world of 3D, while SolidWorks 2005 gives increased sophistication and more tools to those who prefer its relatively easy to use approach. The vendors of all three packages emphasise improvements in exchanging data with each other, recognising the need for CAD model exchange between different systems in the real world, however undesirable this might be.

Bill McClure, vice president MCAD R&D for UGS told Eureka, "We would certainly be pleased is users replaced all their other CAD systems with solutions from UGS. Realistically, however, we have to accept that users work in a multi-CAD system environment, whether other systems are inherited, come with acquired businesses, or are used by customers or suppliers. We therefore provide tools to interface to other systems. However, if you work with multiple systems, my advice is that you should aim to keep the data flowing in one direction rather than send it back and forth.

"Design of large systems is one of the strengths of NX. We have customers that are using NX to design products in the automotive, aerospace, consumer products and industrial machinery markets. Some of our customers routinely designs assemblies with 40,000 or 50,000 parts."

NX3 will also incorporate DesignLogic, which enables engineers to embed design knowledge and engineering rules into their model data. For example, the diameter of a drive shaft may be determined by the required transmission torque and material specification. UGS says that the rules that calculate the feature sizes of the shaft can be built directly into the model and are automatically re-evaluated if requirements change. A user interface guides users through the creation and selection of rules. It is intended that companies should use this to create custom libraries of functions and knowledge enabled design features that can be published to the whole enterprise to promote the re-use of best practices within the organisation.

We asked if this was not dissimilar to capabilities incorporated in Catia, to which McClure responded, "We consider we offer superior facilities to Catia Knowledgeware. Our NX Knowledge Fusion is based on the Intent Knowledge Engine, which is a classic order independent declarative solver that will solve a set of rules."

Looking to the future, colleague Ted McFadden, vice president manufacturing R&D said, "My own opinion is that we have spent five years developing associative geometry. The next thing is going to be the Bill of Materials, so that when the BOM is changed, it automatically propagates this to manufacturing and assembly and also to disassembly."

Interestingly, the customer chosen to present the practical benefits of working with a pre-release version of NX3 was Giorgio Aldini, president of X-Form Industrial Design based in Regio Emilia in Italy. X-Form does large scale design work such as the bodywork for a Volvo bus, but specialises more in projects like that involved in making a Black and Decker electric pressure washer have something of the style associated with the Ferraris made 30km down the road.

The design process begins with traditional 2D sketches on paper, but these are soon captured and converted to 3D. In Aldini's words, "To cook in 3D you need 3D ingredients." In the case of the Black and Decker washer, he said the design process started with a 3D model of the machinery inside. The block model of the styled casing was broken into three parts and use was made of both the parametrics and associativity in the software. "If somebody changes the master, it will change all the three parts without re-writing parameters." The design process included creating a picture and multi media presentation for the customer, after which we, "Then start adding the technical details. Sometimes you then have to revolution the structure" as he said but, "It is important that this work is done by the designer to retain the original design." He obviously appreciated using DesignLogic to set up rules, observing, "Recording rules is recording products and stories", thus retaining hard learned expertise.

Autodesk products, on the other hand, are traditionally much more associated with draughtsmen doing detailed 2D design work, concerned about tolerances and clearances and whether balloons are drawn according to a particular set of standards. The company is still able to boast what are undoubtedly the world's largest annual sales and installed software bases, whether one cares to measure them by numbers of seats or revenue.

Users considering moving to 3D should therefore be greatly encouraged by the fact that Inventor in its version 9 embodiment, now has all the drawing management facilities associated with Autodesk Mechanical. These include the ability to mix multiple standards in a single drawing, and to update all drawings by a single standards change. Automated tools test for part interference, allowing parts to be measured for proper fit, and it is also possible to vary component tolerance to validate manufacturing flexibility. AutoCAD design templates, including layers, title blocks and standards information can be transferred to Inventor, and conversely, AutoCAD Mechanical can be used to create drawings of Autodesk Inventor part models. When the design is changed in Inventor, it automatically updates the AutoCAD Mechanical drawings.

While component copying is an integral part of any CAD package, that in Inventor now includes an automatic naming functionality to create same-as and except versions of the design while maintaining the integrity of assembly constraints, iMates, Workfeatures, welds and assembly features.

Acknowledging the popularity of AutoCAD and related products, SolidWorks 2005 now includes a DWG embedded editor for 2D AutoCAD files in their native environment. New for machine designers is a library that aggregates in an on-screen window, hundreds of pre-designed parts that machine designers use most. New weldment features automatically generate cut lists, dictate mitred/angled cuts and enable the quick creation of curved segments. In addition to the embedded COSMOSXpress embedded analysis product, the software now includes MoldflowXpress. This allows mould designers to quickly and easily validate whether a plastic injection mould part can be filled.

A new Flex feature allows users to bend, stretch, twist or taper solid bodies at any point or region. A new DrawCompare tool highlights differences between drawings similar to the way in which Microsoft Word tracks changes in documents.

Whereas UGS chose a customer engaged in smaller scale design work than is generally associated with its products, SolidWorks chose Silvertip Design, engaged in the design of the Blade Runner, a revolutionary 38 tonne truck capable of transferring most of its weight onto and being guided by tram tracks. The first demonstration truck is expected to be trialled in the Czech Republic.

UGS
Autodesk
SolidWorks

Eureka says: Never before has 3D CAD been available with so much facility and ease of use. Now there is no excuse at all for continuing in a 2D environment

Pointers

* UGS has finally merged its NX and SDRC families of software into a single environment, tailored for but by no means exclusively used by designers of large and complex products

* Inventor 9 now brings all the drawing management capabilities of AutoCAD mechanical into a true 3D environment and provides an easy upgrade path from 2D to 3D

* SolidWorks 2005 comes with a whole host of enhancements previously only associated with top end CAD or specialised add on modules

Author
Tom Shelley

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