CAD- The community has some concerns…


Ryan Earle

 Cloud based CAD

‘Cloud’ is all the rage. The hype is there anyway. What is the reality though when it comes to CAD?

Various vendors are toying with the idea of CAD in the Cloud and others (very few) have full cloud based hosted systems that are severely limited in capability, at this stage.

If you step back and think about it, complex product design and the process around it is collaborative by nature and one would think having a cloud based solution makes sense. This is where I believe you would be wrong when it comes to CAD. Yes, the collaborative nature of product development is real, but this is not the CAD itself but the PLM environment around CAD and then into manufacturing and assembly.

We have very mature PLM platforms for global collaborative product development. When it comes to CAD however it’s often about large assemblies, complex geometric relationships between parts, common parts use, assemblies and file transfer traffic. This is all relatively heavy IP that technically is a challenge to offer fully in the cloud and offer the full host of features especially related to the assembly structure driven from CAD.

This is not really the important issue however as advances are being made as we speak and these challenges will become less over time.

The fundamental issue is actually about who has the control!

It would be in the best interest of the vendor to have the control and charge their clients on a subscription basis to keep working.

As a user or business owner, wouldn’t you rather be in control of your data?

Another major factor is reliability of the platform. The data centres and servers are one thing but there’s also the underlying internet dependency, the cost and performance thereof, especially in South Africa and the other parts of our continent.

There seems to be a rising resistance to Cloud-Based CAD that is not difficult to understand. Let’s see how things develop.

Geometry Kernel concerns

When it comes to the fundamentals of how CAD systems are structured, there are a number of ‘layers’ that make everything happen.

Think of this like a peach perhaps: The pip, the flesh and the skin.

See CAD like a peach – The Pip, The Flesh and The skin.

See CAD like a peach – The Pip, The Flesh and The skin.

The pip: At the core of all 3D based CAD, CAM and CAE software is the ‘Geometry Kernel’. This can be seen as the maths ‘engine’ that is used to define the shape of the 3D geometry.

Now the flesh: In the CAD world, we have the geometric constraint solving layer. This is the code layer that deals with positional and relational data that is used create or manipulate the 2D or 3D geometry and presents this to and accepts inputs from the User Interface (UI), which is the third layer, the skin.

Probably the most popular geometry kernel in the 3D world is Siemens’ Parasolid used in well-known CAD offerings such as Siemens’ NX, Solid Edge, and yes also Solidworks and Bentley’s Microstation as well as the fairly new cloud offering, Onshape and others.

We also have Dassault Systèmes ACIS kernel. This is used for example in PTC’s Creo and others but ironically not used in either Catia or Solidworks. (Both Dassault products!) There’s a very good reason for this- It’s very, very difficult to change the kernel without introducing many problems. Back to the peach; Try taking out the pip without making a sticky mess!

Autodesk uses an evolution of ACIS known as ShapeManager.

Dassault Systèmes who develop Solidworks seems to have unsettled their user base by not having a clear and consistent message when it comes to choice of kernel for Solidworks and how or when to change to something else. (Ideally one of theirs, CGM or ACIS it would make sense it seems)

It has to be fairly uncomfortable for Dassault Systèmes to have to rely on Siemens’ Parasolid kernel as well as the Siemens’ D-Cubed constraint solving technology that underpins Solidworks. It’s really only the User Interface layer they have any control over, Ouch!

This does, like it or not, put Siemens in a very strong position to optimize the interactions between these layers as this is their own technology. This manifests as a richness of features, better performance and stability and innovative offerings such as ‘Synchronous Technology’ in their Solid Edge and NX products.

Conclusion: Kernel politics is messy in the CAD world and manifests as issues in data translation, interoperability, and stability and hinders system innovation.

System reliability/stability

The CAD market has evolved to a point where there is a fair amount of pressure in offering more features for less money, with new entrants to the market challenging the more established offerings, on features and price. One of the areas to suffer is system stability or reliability.  Software development that results in a stable, pleasant user experience with minimal errors is a real challenge.

No solution is perfect but the leading solutions are fairly stable with some better than others. The acid test is where real-world usage deals well with large assemblies, high levels of complexity of associated data and we have an optimal interaction between the User Interface, the Geometry Constraints engine and the Kernel and back again, over and over again, click after click. This all in an integrated managed, structured environment for controlled release to production.

It’s a big ask!

Subscription based access

Regarding subscription, Autodesk for example, are moving to a subscription-only model to make their products available to the market. For some this may be welcome. Others may not like the idea of being forced to access the software they have ‘owned’ in the past in this way.

On the other hand, subscription does allow short term cost effective access as and when needed, even though total cost of ownership is higher. This is a good thing but should be offered as an option. It makes sense to have both perpetual as well as subscription. This gives the users a choice based on their business needs and cash flow challenges.


We are seeing interesting developments in Cloud based access, mobile device based access including simpler initial concept development methods such as Catchbook from Siemens and Fusion 360 from Autodesk. Vendors are offering access via subscription more than ever and certainly CAD is getting cheaper as there is more choice. Kernel uncertainty is there for some. Fundamentally though, when it comes to delivery of product, its about using real CAD to drive real BOM’s and the real challenges in Planning, Simulation, Production, dealing with change, accelerated product delivery cycles, global supply chain, integration to ERP, MOM (Manufacturing Operations Management) and In-Service support.

Actually, it’s not about the Peach!