Direct modeling: magnetic JENGA in outer space

CAD stands for Computer Aided Design. If you are using a 3D CAD tool in a product development company today, there’s about a 99% chance it is a history-based (AKA feature-based), parametric design tool.

VP of Engineering:
“Huh? Really? I’m not sure about that. I think we just use regular-old-CAD. We’re on Pro/Engineering.”

FEA Analyst:
“Ok, whatever. Our design guys do that stuff for me, and they’re damn good at it.”

Designer:
“Well, duh, all 3D CAD is parametric. That’s kinda the point.”

History-based CAD is so prevalent that most people in industry have no idea what the “history-based” part even means. “It’s just CAD, right?”

So, let’s chip away at the semantics. History-based refers to the set of steps most CAD tools use to define and create 3D objects on your screen. This works a bit like MS Excel macros. Every step the CAD Designer used to create that object gets “replayed” (in order) to redraw or “regenerate” the object each time you want to see it.

This term “design intent” gets tossed around a lot in CAD. In a history-based tool, the Designer needs to carefully think through how the object should be constructed before he begins constructing it. He needs to envision what changes people might want to make to this model in future revisions, and make sure the steps required to regenerate the model allow for those tweaks.

For example, a CAE analyst typically wants to de-feature a CAD model prior to simulation. He may want to simply remove an unnecessary hole… but if the next 2 steps in the “macro” of creating the part reference that hole, all hell breaks loose.

The model will “fail to regenerate.” The process of killing holes, fillets, and other noogies unnecessary for simulation can become a grueling game of JENGA. Remove the wrong piece in the wrong order, and the tower falls.

Direct modeling (AKA history-free modeling) offers a beautiful alternative for CAE analysts needing to prep manufacturing-ready models. Direct modeling doesn’t replay a macro to display a part on the screen. It just displays the part in its current state. You are free to slice, dice, move, push, pull, and manipulate the model with no fear of regeneration failures. All the unaffected parts stay where they are supposed to on the screen.

In this rough analogy, it’s a bit like playing magnetic JENGA in outer space.

Filed Under: Direct Modeling
January 3, 2009
  • http://jonbanquer.wordpress.com/ Jon Banquer

    SpaceClaim is still looking for it’s market and by hiring you I guess they want to make a run at CAE. Please let me know when SpaceClaim finally realizes that high-end CAM running inside of SpaceClaim is just as big if not bigger of a market and badly needs to be addressed.

    You don’t get much weaker CAD than what is in Mastercam, Surfcam, Gibbscam, Featurecam, DP Esprit, etc. Any idea how much this slows down actually making the product? Here are some clues for those who don’t know much about CAM:

    In order to lay down toolpath you need a “road”. That road often called chaining and quality chaining is badly lacking in all the above mentioned CADCAM products. So is the ability to quickly and easily make major modifications to solid models to make then possible to machine.
    Going back and forth between different CAD and CAM products wastes time and is fraught with problems. Most of the development for mid-priced CAM products seems to be going into getting existing CAM products to run inside of SolidWorks. This isn’t a very good long term solution. A much better solution would be for these CAM companies to license the source code to SpaceClaim or create a licensing agreement that’s beneficial to both parties.

    Jon Banquer
    San Diego, CA

  • http://jonbanquer.wordpress.com/ Jon Banquer

    SpaceClaim is still looking for it’s market and by hiring you I guess they want to make a run at CAE. Please let me know when SpaceClaim finally realizes that high-end CAM running inside of SpaceClaim is just as big if not bigger of a market and badly needs to be addressed.

    You don’t get much weaker CAD than what is in Mastercam, Surfcam, Gibbscam, Featurecam, DP Esprit, etc. Any idea how much this slows down actually making the product? Here are some clues for those who don’t know much about CAM:

    In order to lay down toolpath you need a “road”. That road often called chaining and quality chaining is badly lacking in all the above mentioned CADCAM products. So is the ability to quickly and easily make major modifications to solid models to make then possible to machine.
    Going back and forth between different CAD and CAM products wastes time and is fraught with problems. Most of the development for mid-priced CAM products seems to be going into getting existing CAM products to run inside of SolidWorks. This isn’t a very good long term solution. A much better solution would be for these CAM companies to license the source code to SpaceClaim or create a licensing agreement that’s beneficial to both parties.

    Jon Banquer
    San Diego, CA

  • Jeff Waters

    Hey Jon, thanks!
    Yes, I absolutely see a ton of value-add for Direct Modeling on the CAM side of things.

    In fact, I really do view the opportunity for SpaceClaim to be the circle of people and functions surrounding the hardcore Design department.

  • Jeff Waters

    Hey Jon, thanks!
    Yes, I absolutely see a ton of value-add for Direct Modeling on the CAM side of things.

    In fact, I really do view the opportunity for SpaceClaim to be the circle of people and functions surrounding the hardcore Design department.

  • http://jonbanquer.wordpress.com/ Jon Banquer

    “In fact, I really do view the opportunity for SpaceClaim to be the circle of people and functions surrounding the hardcore Design department.”

    So do I. History based modeling is the wrong tool for any CAM user who has to work with other peoples designs and modify them and it’s the wrong tool if you have to work with non-native solids. The problem is most CADCAM users are totally blind to the problems of history based modeling because for many years they have suffered with outdated wireframe based CAD with crude solid modeling thrown on top. Now for the first time they finally have a modern CAD front-end with SolidWorks to work with. As a result of this situation most CADCAM users just aren’t able to be objective about the inherent problems with history based solid modeling.

    They only company that I know of that truly sees the big picture is Siemens with NX 6. When you combine their outstanding CAM with their Synchronous Technology tools you get the best solution on the market.

    Unfortunately for Siemens I’m not a product loyalist like most users are and I think there should be many choices available. In order for other choices to be available SpaceClaim and CoCreate are going to have to make major marketing / direction changes to become truly viable and truly complete solutions. I’d love to be able to consider SpaceClaim or CoCreate but I can’t because of what I feel are very poor marketing decisions on the part of both companies. PTC has never really understood CAM and it shows. NX, formally Unigraphics stated as a CAM solution and it developed into a CAD solution and to this day this makes a huge difference and this also shows.

    I’m one hundred percent certain that only fresh faces in companies like SpaceClaim and in CoCreate can make a difference and make SpaceClaim and CoCreate truly well rounded and more complete solutions.

    In the mean time most development of CAM is headed for SolidWorks and I think this is a very unbalanced approach that isn’t the right answer for sure isn’t a good long term solution to the massive problems with history based modeling that simply aren’t going to go away.

    By way of example, SmartCAMCNC could easily go from being seen by most as a totally obsolete product that has faded from glory to being seen as a market leader once again just by licensing SpaceClaims source code or by setting up an agreement where SmartCAM runs inside of SpaceClaim.

    Jon Banquer
    San Diego, CA

  • http://jonbanquer.wordpress.com/ Jon Banquer

    “In fact, I really do view the opportunity for SpaceClaim to be the circle of people and functions surrounding the hardcore Design department.”

    So do I. History based modeling is the wrong tool for any CAM user who has to work with other peoples designs and modify them and it’s the wrong tool if you have to work with non-native solids. The problem is most CADCAM users are totally blind to the problems of history based modeling because for many years they have suffered with outdated wireframe based CAD with crude solid modeling thrown on top. Now for the first time they finally have a modern CAD front-end with SolidWorks to work with. As a result of this situation most CADCAM users just aren’t able to be objective about the inherent problems with history based solid modeling.

    They only company that I know of that truly sees the big picture is Siemens with NX 6. When you combine their outstanding CAM with their Synchronous Technology tools you get the best solution on the market.

    Unfortunately for Siemens I’m not a product loyalist like most users are and I think there should be many choices available. In order for other choices to be available SpaceClaim and CoCreate are going to have to make major marketing / direction changes to become truly viable and truly complete solutions. I’d love to be able to consider SpaceClaim or CoCreate but I can’t because of what I feel are very poor marketing decisions on the part of both companies. PTC has never really understood CAM and it shows. NX, formally Unigraphics stated as a CAM solution and it developed into a CAD solution and to this day this makes a huge difference and this also shows.

    I’m one hundred percent certain that only fresh faces in companies like SpaceClaim and in CoCreate can make a difference and make SpaceClaim and CoCreate truly well rounded and more complete solutions.

    In the mean time most development of CAM is headed for SolidWorks and I think this is a very unbalanced approach that isn’t the right answer for sure isn’t a good long term solution to the massive problems with history based modeling that simply aren’t going to go away.

    By way of example, SmartCAMCNC could easily go from being seen by most as a totally obsolete product that has faded from glory to being seen as a market leader once again just by licensing SpaceClaims source code or by setting up an agreement where SmartCAM runs inside of SpaceClaim.

    Jon Banquer
    San Diego, CA

  • http://p-hamilton.blogspot.com/ Paul Hamilton

    Nice post Jeff, and good analogy. I like it.

    Jon – I think CAD vendors look at it this way:
    Of all the consumers of mechanical 3D CAD, what percentage of those users need to generate tool paths? Of those, what percentage require tight integration with a single CAD tool? It is not insignificant, but probably low, especially since most of these only know history-based modeling and live with the related issues. We just need to keep educating them.

    Paul

  • http://p-hamilton.blogspot.com Paul Hamilton

    Nice post Jeff, and good analogy. I like it.

    Jon – I think CAD vendors look at it this way:
    Of all the consumers of mechanical 3D CAD, what percentage of those users need to generate tool paths? Of those, what percentage require tight integration with a single CAD tool? It is not insignificant, but probably low, especially since most of these only know history-based modeling and live with the related issues. We just need to keep educating them.

    Paul

  • http://jonbanquer.wordpress.com/ Jon Banquer

    Paul,

    I firmly believe I could help to make the educational problem you speak of get solved a lot quicker if PTC created or purchased a great CAM program that could be fully integrated and ran completely inside of CoCreate. The same holds true for SpaceClaim.

    Next best would be to have an independent CAM maker do this. See my blog for a page I put up today that makes the case for this.

    Jon Banquer
    San Diego, CA
    http://jonbanquer.wordpress.com/

  • http://jonbanquer.wordpress.com/ Jon Banquer

    Paul,

    I firmly believe I could help to make the educational problem you speak of get solved a lot quicker if PTC created or purchased a great CAM program that could be fully integrated and ran completely inside of CoCreate. The same holds true for SpaceClaim.

    Next best would be to have an independent CAM maker do this. See my blog for a page I put up today that makes the case for this.

    Jon Banquer
    San Diego, CA
    http://jonbanquer.wordpress.com/