u p F r o n t . e Z i n e

celebrating 15 years of reporting on the business of cad

Issue #645 |  May 11, 2010  |  English Edition

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In This Issue

1. All About D-Cubed's 2D DCM

     - Q&A


2. American Imaging Services vs Autodesk


3. And in Other News



All About D-Cubed's 2D DCM

Neil Howarth is the business development manager for the D-Cubed Components business of Siemens PLM Software. He took a few moments out of his busy schedule to speak with upFront.eZine about the D-Cubed business, particularly their 2D Dimensional Constraint Manager (2D DCM) sketcher engine.


D-Cubed produces the underlying 2D and 3D geometric constraint solving technology used by Siemens PLM Software and many other developers of CAD, CAM and CAE vendors. Developers license the D-Cubed Components to rapidly provide constraints to users, and to reduce the costs compared with developing and maintaining such software in-house. The components business at Siemens PLM Software is also known for their Parasolid solid modeling kernel.


The first reference to CAD-like geometric constraint solving known to Dr Howarth was in a system called Sketchpad developed by Ivan Sutherland, later of Evans and Sutherland fame, in the early 1960s. The technology then began appearing in commercial applications in the mid-1980s, including products from the Massachusetts-based Cognition and then soon afterwards from PTC. The 2D DCM may be the first appearance of this technology in component form in 1990.


D-Cubed was founded in 1989 by John Owen, who with his mathematical and then solid modeling technical background was ceo and chief technologist for the first 15 years. All the developers have a technical background, mostly in math, physics, engineering or computer science, many with PhDs. The company was acquired by UGS in 2004, which in turn was acquired by a private equity firm, and then sold to Siemens.


The D-Cubed business produces a half-dozen packages of component software, of which the best known is  2D DCM, short for two-dimensional Dimensional Constraint Manager, a literal name decided upon by the non-marketing people in the early days of the company.


The purpose of the 2D DCM is to control the sketches in CAD systems by applying simple geometric rules to geometries: be horizontal; be connected; be fixed in place; be of a specific size; and so on. There is the criticism that parametrics make CAD systems more difficult to use, because it takes some time to learn how to use it. However, it has become so prevalent that once you learn it, it can be a faster approach to designing and editing models. Once you learn it on one CAD system, you can use it on others;  And you don't have to use parametrics if you don't want to.


Because it is an underlying component, it has no graphics of its own, and so it is up to programmers at the CAD vendors to figure out how much of the DCM’s capabilities to implement, and what it will look like on the screen. The CAD program makes calls to DCM, (adding geometry, dimensions and constraints), and then get answers out of it (locations of the geometries that satisfies the dimensions and constraints), updating the image on the screen to take account of the parametrically modified model. DCM works with vector geometry from any source, not just the sketches found in CAD systems; a diagramming program like Visio could conceivably use it.


Dr Howarth showed me an in-house app used to demo and testi many of the 2D DCM's functions. For instance, D-Cubed's demo app highlights the dimensions and constraints that are overconstraining the sketch. The user can remove any one of them, not just the last one added, in order to produce a model that's well defined. It highlights geometry that is underdefined, and allows you to drag thegeometry around the screen. A function in the demo system called "Wobble" moves all elements that are not fully constrained, which lets the user see the "loose bits", indicating where dimensions and constraints need be added to fully define the sketch. An auto-constraining and dimensioning capability can automatically define the model, albeit the final layout of the dimensions needs to be clearned up by the user. The demo lets you see which capabilities are still missing from the CAD package you use!



upFront.eZine: Why wouldn't a CAD vendor write their own DCM, as a number of CAD vendors have done with solids kernels?

Dr Howarth: A few vendors have written their own geometric constraint solvers, presumably so they can control their technology. Several factors can be involved for those that have chosen to adopt the DCMs. Having been in the business since 1989,  we have solved many of the common issues to a high standard. And, with such proven components the vendor can be sure they will get to market more quickly, with lower overall development costs. The component business model in the CAD, CAM, CAE industry has much in common with other industries, e.g. automotive. Automotive OEMs generally don’t produce all the parts of a car in-house. The same goes for many CAD, CAM, CAE vendors, who choose to build their applications on software components, enabling their developers to better focus on their specific areas of expertise.


upFront.eZine: Who are your competitors?

Dr Howarth: There aren’t many. The market for geometric constraint solving components is small compared to, say, the market for end-user CAD applications, and so there is not sufficient business to sustain many component providers. For the DCM geometric constraint solving components, LEDAS, based in Russia, is a relatively recent entrant. In a broader longer-term sense we have always been competing with those application development teams that prefer to develop similar functionality in-house, working to try to convince them of the benefits of the component business model, and our technology in particular.


upFront.eZine: What about 3D?

Dr Howarth: We have the 3D DCM, which is very similar to the 2D DCM, with the additional capability that it can solve 3D models. It is used to solve the dimensions and geometric constraints that help to position parts in assemblies or kinematic mechanisms, the geometries in 3D sketches, including piping and wiring layouts, and for the direct history-free control of the shape of 3D parts.


upFront.eZine: What is the future direction for the DCMs?

Dr Howarth: For the 2D DCM, it is has been quite intensively developed for more than 20 years, and is already quite functional. The focus is therefore on satisfying the detailed requirements that come in from its very large customer base, be it for new capabilities, better performance, or fault fixes. However, an interesting current development driver is the more recent adoption by the AEC (architecture, engineering, construction) vendors of their version of the parametric modeling techniques, including Building Information Modeling, that have been found in the mechanical CAD applications for more than 20 years. In recent years the DCMs have begun to be taken up by the AEC vendors. It’s interesting to see, in some sense, this aspect of the technical history of the CAD market, that is parametric modeling, repeating itself.


The 3D DCM has been around for a long time too, but in some ways the current pace of progress in application usage is more intense than for the 2D DCM, for example as the engine for a new generation of direct modelers, or the extension of 2D sketching techniques into three dimensions. The technical challenges in 3D are always that bit more intensive than in 2D.


upFront.eZine: Have faster computers had an effect on DCM?

Dr Howarth: The 2D DCM, for typical sketches, has had pretty good performance since first  release, being largely interactive 20 years ago, and very interactive today. Such performance uses a range of solving algorithms based on original work by the founder, John Owen, continuously “tuned up” over the years. However, as more CAD systems become parametric, on occasion very large drawings are now being constrained, and faster computers always help here. 3D solving using the 3D DCM has always been relatively more intensive than in 2D, and here the availability of faster computers has always been helpful.


We’ve made no mention of the D-Cubed Hidden Line Manager and Collision Detection Manager so far, though these components are hungry for computer power. There are possibilities for exploiting the power of multiple-processors in these functional areas in the near future.


upFront.eZine: The problem I have with constraints is knowing when a design is fully constrained.

Dr Howarth: Good point. A design does not need to be fully constrained, but if it is, that removes most of the ambiguity about subsequent solving behaviour. So, as we saw in the demo app, there are numerous approaches to this issue. The DCMs can identify the underconstrained parts of the model, and in many cases show the specific nature of the remaining freedoms, e.g. the fact that a part can still rotate about an axis. The user can drag underconstrained elements, with the resulting motion illustrating the remaining freedoms. The wobble function can jiggle the freedoms automatically, again revealing to the designer what remains to be constrained. Finally, if the user wants an automatic solution, the 2D DCM, in conjunction with the application, can automatically provide a dimension and constraint scheme that will fully constrain the model.


upFront.eZine: Where does the D-Cubed name come from?

Dr Howarth: From D times D times D, indicating that the products are relevant to 3D geometric applications. D times D times D can be written as D to the power of three, which when read out loud is “D Cubed” Add the hyphen, and there you have it, “D-Cubed”.





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American Imaging vs Autodesk

Autodesk's purchase of Softdesk proved to create a "problem" named IntelliCAD, and now we learn of a second problem. American Imaging Services last year sued Autodesk over a patent AIS holds on manipulating raster images inside of CAD systems. US patent RE40,384E (first filed in Nov '92) covers a software program that does the following:

It is page 2 of the patent paperwork that lists "Other Publications" and whose titles make interesting reading for supplemental searching. From here, we learn that AIS sued Intergraph in 1997 over this patent, and seven long years later Intergraph's lawyers had the suit dismissed. (Anatech was the name of Intergraph's scanner division.) Learning from the mistakes it made, American Imaging then filed to modify the patent in 2004, and got it approved in June, 2008.


Less than a year later, AIS filed suit against Autodesk in Texas court. It involves Autodesk's Raster Design software, it is on-going, and that's all I know about the case for now.


The patent's "Other Publications" list includes a reference to Robert Godgart. He headed up Image Systems Technology and I recall his phone call to me in 1988, when I still work as technical editor at CADalyst magazine. He excitedly told me that he had figured out a neat way to edit raster images inside AutoCAD, something that had become possible because of Autodesk's then-new ADI [AutoCAD device interface]. ADI allowed AutoCAD to display data from just about any source, making also possible the then-burgeoning display-list technology.


In my report "CAD in Russia," I noted that the programmers behind Nanosoft licensed some of their code to Image Systems for CAD Overlay. Mr Godgart's company was purchased by Softdesk, where he was vp of technology partnerships. Softdesk was purchased by Autodesk in 1996. (The other item that came out of that purchase was IntelliCAD.) Mr Godgart went on to found PowerAdz.com and AutoTask.


You read a bit of CAD Overlay's history at http://spatialnews.geocomm.com/whitepapers/cov_selecting.html. Autodesk alter renamed CAD Overlay as Raster Design 2004.


CAD Overlay's technology seems to pre-date (aka prior art) AIS's patent application. Perhaps not. Another law suit (involving the bankruptcy of an investor in AIS) tells us that William Opincar founded AIS in 1986 "to design and develop software and programs which enable manually generated engineering drawings to be converted to computer-readable form for use in computer-aided design systems". He still heads the company.


AIS lost its suit against Intergraph, re-wrote its patent, and then went after the third-generation owner of Image Systems' technology.







And In Other News

Autodesk's mantra is "We don't do PLM," and so today PTC announces Windchill ProductPoint for managing AutoCAD data.


In unrelated news, former Windchill ceo and current PTC cto Jim Heppelmann moves up to PTC president and ceo on Oct 1, with current ceo Richard Harrison becoming executive chairman.


Bad news for Dassault Systems: Fiat is requiring Chrysler to switch from Catia to NX from Siemens PLM Systems. GM's contract with Siemens PLM Systems is up for rewewal.



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Letters to the Editor

As  your readers take interest in PLM-related issues I thought that they maybe would like to share a PLM TV News-report on Toyota, just published on YouTube. The sticky accelerators has caused a mountain of problems for Toyota. Only a year ago a Toyota-product was simular to quality, lean production and technology leadership in general. All that has changed and the tough implications for the company has escaped nobody. But today it also raises questions on the roles of PLM- and simulation-systems. PLM TV News has talked to industry analyst Joe Barkai, IDC Manufacturing InSights, Jim Heppelmann, COO PTC and Helmuth Ludwig, President of Siemens PLM Software. Here is the link: http://www.youtube.com/watch?v=6ng-xW6pDPY

    - Verdi Ogewell, editor-in-chief

    VerstadsForum PLM Magazine



Thanks for your update on TurboCAD vs DoubleCad XT Pro.  I have been wondering the same things myself.  I stayed with TurboCAD for years until they had a few bad releases in a row and I felt I needed to get on the ACAD LT routine.

    I recently picked up DoubleCad XT Pro r2 and it is sweet.  Already dumped AutoCAD again as I declined to renew [the subscription]. Now I'm thinking I'll look into TurboCAD again with 17.

     You must have been reading my mind. They recently phoned  me to promote TurboCAD 17.  When asked if I had any recommendations, I suggested that they go after Revit in a big way. I can only hope..

    - Lloyd Dhymaxion


Re: upFront.eZine's 15th Anniversay

Alright, we took time out from our celebrations of the 15th year anniversary of upFront.eZine -- Jon was just cutting the cake -- and I sent you $25. Hope all is swell with you.

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    Jon Peddie Associates


The editor replies: I hope it is chocolate cream; I really like chocolate cream.


Ms Maher responds: Here ya go:


Happy Birthday!!

    - Allan Behrens



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