Brave new world in 3D solid modeling


The market for advanced software that could create models for designs and products in 3D really came into existence back in the 1980.

Historically, it has been ‘feature-based’ or ‘history-based’ 3D CAD tools that have dominated the market. In the early days it was not inevitable that the methodology would prevail, but its success has largely been attributed to the limits of processing power delivered by computers of the time.

Because of the lack of number-crunching performance available, feature-based modeling held the advantage over alternative methodologies such as direct modeling. Essentially, it was based on a clever trick to make solid modeling viable on hardware of the 1980s.

Feature-based modeling broke down the design into a list of individual parameter-driven steps or ‘features’, which acted as instructions to create the shape of the part and enabled the hardware to create and work with models in something like real time, or at least vaguely approaching it.

Certainly the process worked well enough for designs comprising simple parts and assemblies, but as computers delivered increasing performance, the models became more complex, and additional concepts were developed to link the features together.

These included constraints and parent-child relationships, which basically describe the relationship between the individual features or steps, held in the tool’s ‘history-tree’. However, it meant that if a specific feature needed to be changed, then it was necessary to retrace the steps right back to the definition of that particular feature.

Feature-based modeling also required the creation of interfile dependencies and eventually the development of data-management tools to enable concurrent working of design teams.

Barriers to entry

In addition, while the 3D software was powerful, and also generally expensive, it was only the experts in CAD that could use it. It is estimated that approximately 25 million users globally, including electronics and mechanical engineers, would benefit from using 3D design.

Yet only one million CAD seats have been sold in total across the major CAD software vendors. Many of those that could have benefitted from 3D design have not been given access to this mysterious and impenetrable knowledge, most likely for reasons of cost: both in terms of tool price and also the time it takes to become skilled and fully productive with the tools.

Both of these factors have become the major barriers to entry for users looking to reap the benefits of 3D design capability.

The latest tools from leading CAD vendors are in the range of $5000 to $30,000 per license, and usually come with high-priced annual maintenance fees. As mentioned above, the second impediment has been the significant learning curve sometimes associated with traditional 3D modeling.

Entry-level users may take anywhere between 6 and 18 months before they become fully productive with an advanced 3D tool. Often, this can lead to CAD designs being outsourced to a CAD specialist company, which can introduce bottlenecks in product development with the processing of even simple changes in the design taking many weeks.

Direct modelling

Today computers are something like 100,000 times more powerful than their venerable ancestors of the 1980s. And because of this, direct modeling – which allows a user to draw 3D shapes as easily as they might draw with pen and paper – is making a serious claim as an alternative or, in many cases, a complementary 3D design tool.

Direct modelling offers a large advantage for non-CAD specialists in that it is generally more intuitive and very easy to learn. Direct modelling technology has been described as being like modelling with virtual clay.

Essentially, it is all about geometry; there is no feature history and no need to manage any of the associated complexity such as constraints or parent-child relationships.

It works at the base geometry level and dynamically changes any requested modifications into geometry and explore ideas and product concepts in 3D.

In many respects it is very similar to Google SketchUp, where a user can push and pull on geometry and make new designs extremely quickly.

Direct modelling eliminates many of the problems associated with traditional feature-based tools, as engineers that may not use CAD on a regular basis easily can make changes to models without having to fully understand all the ‘constraints’ of a feature-based model.

For example, with direct modelling the engineer can make an iteration to the design directly from the last one, adding and removing from the design without any problems.

However, it is also very true that some applications will still require feature-based modelling if, for example, it is the end goal to create customised variants of an extremely complex assembly of parts with critical and well-understood relationships and requirements.

However, this approach can be inefficient for significantly smaller designs and direct modeling is quicker and easier for a growing number of applications.

Another advantage offered by direct modeling is greater interoperability, whereas proprietary feature-based systems have incompatible data formats. Historically, competing 3D CAD vendors have had some very different ideas about the operation of features and relationships within their respective tools.

This meant the creation of proprietary software packages that had no compatibility with one another, meaning that interoperability problems have become a significant challenge for CAD users, their colleagues and also in the supply chain. In the past this has meant that everyone in the supply chain had to use the same tools, as there is always some loss of information when translating data from one CAD data format to another.

Employing advanced direct modeling tools such as SpaceClaim Engineer, for example, users in simulation or manufacturing departments can simply edit the actual CAD geometry via STEP files, the most common intermediate data translation format for CAD systems.

Another important advantage of direct modeling is that it allows very quick iteration on concepts, whereas traditional CAD can often be a cumbersome approach, when conceptualising new ideas in response to RFQs (Request-for-Quotation) for example.

DesignSpark Mechanical

While there is no doubt that traditional feature- or history-based CAD tools have a continuing and important role to play in the development of electronics and mechanical design, direct modeling is making a substantial case for use in product development, especially in concept design and prototype manufacturing, but also in other areas. RS and Allied have recognised this important trend and launched the DesignSpark Mechanical 3D solid modeling and assembly tool.

Developed in conjunction with SpaceClaim and primarily based upon the company’s direct modeling ‘SpaceClaim Engineer’ 3D design tool, DesignSpark Mechanical is available for download, totally free of charge to all.

DesignSpark Mechanical offers major benefits to industrial designers and electronics design engineers among many others, such as sales, marketing and production, who can now easily contribute and collaborate at the early stages of product development. Clearly, as a free tool, there is no cost barrier to entry and, based on direct modeling, it is also highly intuitive and extremely easy to use.

Electronics and mechanical engineers and other users can become fully conversant with the software within days or even hours.

Basic designs can be achieved quickly via software’s four basic tools: ‘Pull’, ‘Move’, ‘Fill’ and ‘Combine’, and, unlike traditional feature-based tools, the software makes use of familiar ‘copy and paste’ keyboard shortcuts, for example, allowing exceptionally easy reuse of geometry in different designs.

The tool will enable engineers in electronics and automation markets to be more creative and will also support a more efficient product development process, allowing the production of professional concepts for RFQs right through to delivering highly detailed and dimensioned manufacturing blueprints.

Importantly, the tool can remove bottlenecks in the early design process by making amendments and additions in seconds, rather than having to wait for the CAD department using traditional 3D design tools to rework the design.

DesignSpark Mechanical exports 3D designs in the STL file format to enable rapid prototyping builds and computer-aided manufacturing, in addition to providing the ability to quickly obtain Bill-of-Materials (BOM) quotes via the RS and Allied websites.

The tool can also import circuit layout files in IDF format from any PCB design tool, including the award-winning DesignSpark PCB software from RS and Allied.

3D models

However, it is not just the 3D CAD tool that is important. An absolutely crucial piece in the jigsaw for the electronics and electro-mechanical engineer is a product or component model library.

Approximately three years ago, RS and Allied provided engineers globally with access to an extensive library of 2D and 3D models downloadable completely free-of-charge as part of its initiative with DesignSpark, building up a community of developers to share open-source designs and ideas.

The ModelSource component library contains more than 80,000 component schematics and PCB footprints of semiconductors, passives and electromechanical components from leading manufacturers.

And in terms of 3D, ModelSource also offers more than 30,000 3D models from 45 manufacturers covering key technologies including electronics, electromechanical, mechanical, pneumatics and automation and control. The 3D CAD models are also available in many proprietary file formats from leading CAD vendors.

Key manufacturers represented in the 3D element of the library include Molex, 3M, TE Connectivity, Harting and FCI in the general electronics market, and Siemens, Schneider and SMC in the automation and control applications.


The availability of direct modeling based 3D design tools such as DesignSpark Mechanical and SpaceClaim Engineer, now mean that 3D solid modeling is available to a much wider universe of users, and not just CAD specialists.

These types of tools will enable greater creativity and the fast delivery of concepts and designs for RFQs right through to delivering highly accurate and detailed files for manufacturing.

Furthermore, DesignSpark Mechanical, in conjunction with DesignSpark PCB and the ModelSource library of 2D and 3D component models, will enable engineers to embark upon end-to-end designs with professional-grade tools that are available at zero cost.

DesignSpark Mechanical is available for free download via the RS, Allied and DesignSpark websites. Support for the tool is also available via the DesignSpark community, which also hosts resources for DesignSpark PCB and the ModelSource library.

Eric LeeEric K.H. Lee (pictured alongside) is Technical Marketing Manager, Asia Pacific at RS Components.