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model based definition (MBD) assembly start part


model based definition (MBD) assembly start part



Our company is investigating model based definition for parts and assemblies. Going through the CREO 4.0 tutorial on PTC university, we haven't seen a start part for an assembly. Is there one available?


I don't know if PTC provides one, but I would recommend creating your own that corresponds to your company's needs. The ones from PTC are fairly generic (and I am not a fan of their layering scheme).


Download a free copy of MIL-STD-31000 and you should be able to get all the information you need on setting up an MBD-ready start assembly.

Dave Martin - -

Thanks for that, Dave. Can you elaborate on why the layering scheme (this is the same as states?) is too generic?

Layers are not the same as Combination States.


Layers are collectors of objects in your model, and they are used to perform operations on multiple entities - the most common of which is controlling visibility (e.g., turning off display of some or all datum planes, turning off display of fasteners, etc.).


The Combination States are the heart of MBD, which can include a Saved Orientation, Simplified Rep, Explode State, Display Style, Layer State (which I find don't work that great), and (as of Creo 4.0) Appearance State.

Dave Martin - -



I've been meaning to ask you about your experience with Layer States.  You don't seem too fond of them.







First, I have to admit that I haven't used them since Creo Parametric 2.0. Maybe they have been fixed since then.


I implemented MBD in my company's model templates back then. The recommended schema (I forget where I saw that) recommended setting up some default layer states like All On and All Off. We found that doing anything in the model, related to visibility or not, resulted in the layer state showing up as modified. It was pretty annoying. I stripped the layer states out of the template shortly after.


Which was a shame. The functionality as described back then sounded great.




Dave Martin - -

We are also looking into MBD... The problem I'm having right now is with Assemblies.

I'd like to show a BOM with callouts in the model... (We would like to get away from drawings altogether.)

I'm missing it somehow.  Surely there is a way to do that.      


As you can see by the date of my last post was in 2018, personally I've not worked on this subject for a long time. Although I did lots of work related to this subject, unfortunately I can't give you a definitive answer to your question. PTC supported my efforts with a trial version of Vuforia View, and fantastic tech support on multiple occasions. That said, although the technology of View was incredible in it's potential, I wasn't able to progress to the point where my CREO assembly with all the meta-data in the BOM, such as part numbers, material, etc., was transitioned to an MBD assembly. There was discussion of MBD being addressed in version 7. If this is the case, the MBD assembly BOM would be an earth shaking improvement to the 3D CAD world.

Thank you for the response! 

Yeah... I noticed it was an older post, but it's what came up when I did my search... and it's still relevant.

You just saved me some time... I appreciate that!

I don't see us using MBD for parts an not using it for assemblies so I think this is going to put the brakes on this effort.  We will just wait for PTC to deliver the rest of the tool.


Thanks again.

Michael F. from PTC - the Program Manager for 2D & 3D Detailing / MBD - is developing requirements for adding table functionality as part of MBD, in both parts and assemblies. Mark Nielsen and I had a great conversation with him at the PTC/User winter event in Scottsdale this past January. Mark and I said just give us anything, but Michael is thinking about this very deeply. For example, he's working on supporting both simple tables and Repeat Regions, whether they can be included in Copy Geometry features, should you be able to propagate a 3D table to a 2D drawing, and so on. 

If you are interested in this, I highly recommend getting involved in the working group available here. PTC is not only listening but actively soliciting feedback.


Dave Martin - -

Thank you for the details! 

"Just give us anything"... I love it.. that would be the "Agile" way.


I think most of us have an ERP system that manages the BOMs... but one of our Divisions still puts them on the drawing.  It's nice having a comprehensive document.  

Balloons with intelligent Find Numbers would be good ...


My immediate need today is to be able to add attached leader callouts with the Part Number (without the file extension).  Part Number, Description and Qty would really be cool.  Sometimes, especially during development, this would really be handy.


I've experimented and had some success with Attached Notes although I can't always find the Parameters I need.  I was hoping I could do this with a Symbol so I could hard code the callout syntax.


There may be a way I can do this in CREO 4 (creo 6 later this year) but I just haven't figured it out yet.  


(Switch Dimensions)


Thanks again.



Thanks, Dave for your reply, it's good to hear  PTC is taking this seriously. An elephant in the room sentiment I've had for many years as a designer, "I've already created a project plan, conceptualized the framework of my widget, determined what's off the shelf and what I have to design, and designed everything in 3D. Why am I putting it into a 3-view 2D drawing that's harder to interpret graphically than 3D?" A 3D interactive assembly lets the user interrogate the model for the relevant information they want-the machine shop quoting the part initially needs material and overall dimensions of raw material, and potentially some low level CAM functionality to estimate machining times. Other users providing secondary processes like finishing interpret for heat treats, honing, etc. Assembly folks need detailed assembly instructions, just like the notes on the drawing, with easy ways to explode, and ask for all that meta-data that's often tribal knowledge within manufacturing groups. It's the handle it once principle.

You mentioned getting involved in the working group available here. Can you post that link?

I was involved with the Technical Committees for years. When I and others requested table functionality in MBD, the resistance from PTC was that the intent was not to reproduce a drawing in a 3D model. But the lack of tables prevented the companies I worked for from fully embracing MBD. It wasn't because we wanted title blocks, signature blocks, revision blocks, and BOMs in the 3D model - we wanted people going to Windchill for that information. But there are needs in GD&T and cabling for tables, and in those cases we had to do drawings.

The working groups are on here somewhere. I don't have a link. I'm sure you can find them if you poke around. I have been too busy in the past year to be involved in them.

Dave Martin - -

There's a link to the working groups literally on the home page.

Dave Martin - -