By Dmitry Ushakov (@dmitryushakov)
CEO – LEDAS (www.ledas.com)
The recent announcement of Autodesk 2012 products was intensively discussed on Twitter. My attention was attracted by an interesting discussion about Autodesk’s decision to make Inventor Fusion a part of AutoCAD 2012.
The discussion was started by Blake Courter (@bcourter), a founder of SpaceClaim and ideologist of direct modeling. “Thank you Autodesk!” he wrote. “For what?” asked Deelip Menezes (@DeelipMenezes). “Not making Fusion an individual product? 😉” Deelip meant that Fusion is a competition solution for SpaceClaim. But Blake explained, “For trying to make direct modeling the most prevalent form of solid modeling. And I can’t wait for it to go standalone. Imagine growing up with an iPad and never using a laptop. Now imagine growing up with direct modeling and trying to move to history- based.”
In what followed, Deelip and Blake agreed that the iPad cannot replace a laptop in some things. And neither could direct modeling completely replace history-based approach (albeit the latter is sometimes “awkward and convoluted”). But “the iPad is a version two. SpaceClaim is at version seven. [What will be] In ten years?” wrote Blake. “I suspect my children will never experience regeneration failure,” he added. Later Blake explained to me that he does not have children yet, but hopes to have someday. This raises doubts on his prediction ;-). But he gave at least 20 years to history-based system to retire.
Then Deelip Menezes made an important statement that gave a new impulse to the discussion: “Solid modeling should be more about the thing being modeled and not how you are modeling it.” It attracted attention of Sean Dotson (@SeanDotson), President of RND Automation, a company that engineers, designs, and manufactures custom automation & material handing machinery, including robotic work cells. RND, a longstanding Autodesk customer, was recently named by the vendor as “Inventor of the Year”, which means that Autodesk recognized their design and manufacturing processes as the best practices in the industry. Sean answered to Deelip: “So you are saying the ends justify the means? Nah. I’ve seen some great models that were constructed very badly.” Here I can add that Sean is not the only person who has seen such models ;-). But Deelip refined his statement: “Simply saying that too much time goes in planning how a model needs to be created.”
Indeed, it is very important to make the things simpler, Sean agreed. But “as long as we do not loose the design intent.” Sean needs to be able to know why the part was designed the way it was. A lump without history tells him nothing. He gave an example: “a hole in the middle of a 2″ wide plate. Was the intent to be centered or 1″ from an edge?”
“That example doesn’t need history. Constraints are one way, with varying strengths and weaknesses,” Blake answered. Gold words! Three years ago I wrote a paper “Variational Direct Modeling: How to Keep Design Intent In History-Free CAD”, where the idea of using constraints for editing “dumb” solid geometry was presented. It is a new application of geometric and dimensional constraints, which are now widely used in 2D drawing/sketching and 3D assembly design. But 3D geometric modeling is much more complex! Hopefully recent evolution of solid modeling kernels (like ACIS by Spatial) allowed one to easily update boundary model with the results of constraint solving procedure by just moving/deforming its faces and their boundaries. And the main issue here is to provide user with the solution he/she expects. In other word, the intelligent direct modeling system should be able to recognize and store the design intent within any “dumb” geometry and take it into account when the user changes the model. Constraints serve as a universal language for expression of the design intent here. They are easy to recognize (much more easily than features), easy to keep (thanks to constraint solving technology) and easy to add to existing geometry (you don’t need to reconstruct the model).
Concerning the example given by Sean, I tweeted that an intelligent application should recognize several possible design intents in one model and propose the user to choose the one he/she prefers. Moreover, with constraints the user can express any desired behavior, as in this video recorded a year ago, when LEDAS started to work on the implementation of Variational Direct Modeling in Rhino:
At the end of the discussion Blake Courter came back to the question he initiated it: “Who can give me an estimate of how many Fusion seats will be installed in the immediate future? Anyone think there will be fewer than 1M seats of Fusion issued? That’s about the number of history-based seats under maintenance.”
I visited SpaceClaim.com to find more information about the Blake mentioned. Here is the citation:
It is estimated that the penetration of traditional history-based 3D CAD is very low among more than 15 million engineers involved in manufacturing worldwide, with fewer than one million estimated 3D users in the $5 billion mechanical CAD (MCAD) market.
This estimation seems strange to me, since SolidWorks recently reported 1.4 M installations, and there are some other 3D MCAD systems on the market ;-). On the other hand, we now have Inventor Fusion as a part of AutoCAD (and 1M seats are absolutely reachable in one year), and also SketchUp, Rhino, KeyCreator, CoCreate (Creo Elements/Direct), which total number of seat adds another 1M to the direct modeling pan.
David Levin (@levin_david), LEDAS founder and chairman, noted “Mainstream AutoCAD users will hardly be infected by Direct Modeling. Moreover, I am not sure whether such users will soon go beyond 2D. Finally, I think that a concrete mixed approach of Autodesk may (compared with automatic detection of the design intent) be not optimal for overall global development of Direct Modeling. However my skepticism does not abolish or downgrade significance of the move just made by Autodesk, be it only marketing or not.”
In the neart future, I believe Direct Modeling systems will prevail over history based ones, or at least be compariable. But what’s next? Will the history-based approach be retired? Or will both branches of the 3D CAD tree bear fruits? Can we use any analogy with the iPad/laptop market here? I don’t know the answers to these questions, but expect very interesting and hot discussion at COFES 2011. And of course I’m going to take part in it. 😉
About the Author
Dmitry Ushakov is the CEO of LEDAS Ltd., a Russian-based software development company that provides component technologies and related services for the CAD/CAM/CAE market. He was hired in 1999 by LEDAS to be the lead programmer, and then was promoted to the position of chief technology officer, and later director of product management. During this time, he initiated and supervised the development of LGS, the LEDAS geometric constraint solver, which defined the LEDAS business model for successive years. He is the visionary for a new variational direct modeling technology for the next generation of CAD, as implemented in the series of Driving Dimensions plug-ins for 3D modeling software. In 2011, he was appointed Chief Executive Officer of LEDAS.