Forget the Parametry

caradon · April 2015

@Quentin
I have to agree about Solid Edge ST. 'Synchronous' does look impressive in the product videos and demos, but falls flat on its face when dealing with any moderately challenging geometry.
Synchronous and surfacing? Not happening.
Synchronous and anything beyond prismatic objects? Not happening either.
Onshape's direct edit tools also work best on prismatic parts, but at least their importance is somewhat understated (as I think is most appropriate). Solid Edge pretends ST is the solution to all design problems, while it is only a hammer to a very specific nail...

Dries

Unknown · April 2015

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onshaper · April 2015

Someone in this thread said that parametric is better for machine design. I could not disagree more. Just curious how many guys in here have a decent number of hours on Solid Edge's "Synchronous" environment? You essentially take a solid, throw on 3D PMI style driving dimensions, set up some "live" rules for each dimension, and add 3d constraints when necessary. It's a phenomenal platform and is extremely powerful for machine design, and not much else!

While I love SE's direct modeling environment, Parametric is nice when you already know what your design is going to be. DM is way better if you're not quite sure.

quentin_4 · April 2015

Jon Banquer said:

If these guys don't run out of funding and can make their technology work with 3D sketching things might get interesting for direct modeling:

http://www.cloud-invent.com/about

Jon Banquer
CADCAM Technology Leaders group

This is defenitly what I was talking about! Thanks @Jon Banquer I will survey their developpement.

DriesVervoort_Caradon: SolidEdge was one of the first CAD software to propose both solutions with the same license. Of course they want to promote it as much as possible

Also maybe I guess we must try to change our working uses to adapt ourself to the direct modeling technology. But so far I agree with you, we can't do everything...

Onshaper: I also agree with you, if you are not sure of your expected result, direct modeling is a great tool. Probably the best if you only have a single piece to draw.
If you have many hours on SEST, I could forward you a simple family model and let you try to model it with SEST? It might be an interesting test. Of course it is possible that I missed something as I usually use parametric mode.

What do you think ? ^^

onshaper · April 2015

Hey! I love a challenge. Send it on over. @Quentin

pete_yodis · April 2015

3dcad said:

Pete_Yodis said:

3dcad said:

I don't know much about direct modeling but if all dimension are driven would it make the parametric model open for direct editing and still keep the parameters in place?

Its better than that.

Pete, I'm sorry I didn't understand your comment. Can you open up a bit?

For the topic:
I have tried direct modeling few times but I don't see a reason to 'Move a face' since I can just set new value for parameter to achieve the same.

Only thing it has been good is modifying imported files without history.

Don't get me wrong, I'm not against direct modeling - I just don't know where or how to use it effectively. How do you begin from blank screen with direct modeling? How do you create anything precise without dimensions and if there is dimensions what's the difference then (dimensions are parameters, right?)?

@3dcad As others are mentioning Siemens Synchronous Technology (its in NX and SolidEdge), this is more what I had in mind. As @Dries said it has it's limitations with more organic shapes - but to point out a couple of things... 1) this way of defining/constraining/controlling geometry is kind of a little new, so more capability is being added with each release and 2) You can mix a synchronous tech method with feature based surfaces (and fillets and radii where it makes more sense), and also a conventional direct edit all within the same design. You can get what you want more efficiently. Synchronous tech might not be a catch all or the prized one giant hammer approach, but it certainly makes alot of design much easier. How many times have you come back to even your own model, or some co-workers model and tried to figure out the feature tree. I've been there many times. We can get decent at predicting what changes we might need to make later.. but design is fast moving and changes in ways we can't predict. With history based feature CAD, how many times have you thrown out concept models and re-modeled a production model. We have become CAD weenies over time with our infatuation with design intent on our history feature based CAD models - we've made creating geometry too complicated (from the user perspective... not the folks ensuring the geometry is legit behind the scenes) - it's stuff that should not even be there when we talk about designing physical products. It's like data management for desktop file based CAD - it takes too much time away from just designing and creating. I'm not a user of it but I have been watching it progress for some time and as I understand it so far, Synchronous Technology is really about applying intelligence to control faces of the model. Underlying sketches may be used to initially create the geometry, but they are not what drives the geometry all the time. This makes it awesome for a lot of reasons, one of which is sucking in 3D data that would normally be considered "dumb" and just assigning PMI or GDT (whatever you prefer to call it) to drive the model and change it quickly. This will not create a feature in the tree that then will need to be rebuilt, or be considered with all the other edits that you might have needed with a history based approach. This way of modelling also has appeal to me for model based definition. I want to be able to apply GDT/PMI to the model to control it AND document it at the same time. I then want my drawing (if needed) to just pick that information up and not have to apply another set of "controls" on top of the model, just to document it. With current history feature based approach you could model the geometry one way, want to apply PMI/GDT in another, and in a 3rd way have to document it on a 2D drawing. Too much complication - it needs and wants to be more efficient. I could list more reasons and cases and link up some videos that show these ideas off if you folks want, but I think Siemens and others are really onto something here. Maybe there is also a way to do it even better.

3dcad · April 2015

@Pete_Yodis Thanks for taking time to explain, I need to do some googling on this..

pete_yodis · April 2015

3dcad said:

@Pete_Yodis Thanks for taking time to explain, I need to do some googling on this..

@3dcad I need to spend more time too. My gut tells me this is really, really, good stuff in the long haul. If Onshape could pull this off on their platform... watch out.

mevale · April 2015

3dcad said:

"...I have tried direct modeling few times but I don't see a reason to 'Move a face' since I can just set new value for parameter to achieve the same..."
The first step in the design process is the creativity, find options, find definitions.
Move faces are part of this first stage, the Direct Desing is faster to bring out concepts, and...
when you get the final idea,
Magically you realize that you never did need the parametry!!.
Alleluia!! 8 )

"...Only thing it has been good is modifying imported files without history..."
Wrong.

"...How do you begin from blank screen with direct modeling?..."
You need to be exorcized.
See this example.
https://youtu.be/IyjYzln0B-g

"...How do you create anything precise without dimensions..."
That is the problem with those who are accustomed to the Parametry.
They do believe that it is not possible that there is other design process as they know it, they need to see the dimensions!!
That is almost like a kind of religion.

"...and if there is dimensions what's the difference then..."
The dimensions are the difference!!.
You can delete dimensions, sketches, planes, whenever you want, you are not a slave from them.

Sumarizing.
You don´t need the parametry to do precise parts.

mevale · April 2015

This is a design FULL of hundred of PRECISE prismatics parts started from zero with Direct Desing without Parametry.

What are you talking about?

(This example is not from Synchronous, Synch is still a baby).

Unknown · April 2015

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3dcad · April 2015

So what is the size of that helmet? For child, adult or is it a monument? The problem with cad is that there is no reference to work without dimensions, you can create nice helmet but if the size appears to be 1 cubic meter it's not that useful to protect your head.

Or do you mean that first to make nice looking model and then scale for intended size? This kind of thinking might serve furniture design as well.. hmm
What about standard parts? How do you use M8x30 bolt to connect things if you don't dimension hole&thread for it?

You can delete dimensions from parametric model, then it's just not that parametric anymore.. I'm not slave of dimension, I would say dimensions are my slave and I'm the master who makes them dance

Please do remember, I'm not trying to prove you wrong here - I just wan't to understand how to design without dimension; your religion. I'm almost self learned to cad world (1 course 15 years ago), so I haven't read from the big book year after year that I should use dimensions; I have just found it useful way to make things in right size.

I tried recently software called solid face, at first it felt pretty good. But after sketching everything in place and wanted to set the holes suitable for 8mm dowel, I didn't find dimension tool - exit sketch --> un-install + registry clean.

mevale · April 2015

Hey Jon!

The eternal CAD-Webs Jon.

I remember you, you used to participate in Cadkey forums as mmm... 15 years ago approx?.

C´mon... are your still annoying with Cadkey after so long? Cadkey no longer exist relax.

What am I doing here?

1. I like the idea of CAD in the cloud and I would like to participate.

2. OS is starting and they are asking for ideas, and this is a good time for them.

3 I enjoy reading and talking about CAD and its trend.

4. I like to find old acquaintances.

So... What are you doing here?

Unknown · April 2015

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onshaper · April 2015

I"m confused as to why people say DM doesn't use dimensions...? SE:Synch uses driving 3d dimensions!

ross · April 2015

A case of cannot see the forest for the trees. It is diffcult to concentrate on creative design while dealing with regeneration errors. Onshape has lost me until they provide a serious direct modeling option.

lowjack · April 2015

Just my 2 cents worth - Onshape was started as a parametric CAD modeler, and built around the parametric kernel. If that's not what you're looking for, then so be it. You like direct modeling? Great, use whatever works for you - it looks like Onshape is not it. The work I have to do is almost entirely dimension driven, all mandated by standards - no real room for creative design. I sure as hell would not want to be designing toys, furniture, or consumer goods on SolidWorks, but I don't want the hassle of using Rhino to do the parts and machines I do on a daily basis. Both approaches have their advantages. Trying to get one program to do everything historically results in a program that is mediocre at everything.

3dcad · April 2015

@lowjack Good comment, but if you would design furniture (as I do) you would absolutely wan't parametric modeler with equation editor and 'spreadsheet' driven designs. If you think say kitchen cabinet or wardrobe, they are all the same just with different parameters. This of course depends what kind of furniture you referred to..

lowjack · April 2015

@3dcad - but that's exactly my point. I don't design furniture, and would probably tear my hair out trying to do it with SolidWorks. If I designed furniture, or anything else needing a more free-form type of modeling, I would choose something like Maya or Rhino or any number of other packages meant for that kind of work. Expecting Onshape to change their fundamental structure because you don't use that kind of software is like walking into a baseball stadium and complaining that it's all wrong because you like boat racing.

andrew_troup · April 2015

I think, @3dcad, despite what a dictionary might suggest, your use of "furniture" applies to things most native English speakers would not think of as furniture, but as cabinetry or fitout or joinery or some other term.

Usually most of us reserve "furniture" for chairs, sofas, couches, and other not always upholstered but virtually always movable items, including free-standing chests of drawers, but not (except in more technical contexts) items which are built-in. So it brings to our mind things which are not generally orthogonal or primitive in form.

Your English is so excellent that many here will be surprised at my suggesting you are not a native speaker, BTW, so I hope I have that right (and some may disagree with my guide to usage, which should carry a disclaimer, like all such guides: English usage is notoriously variable)

3dcad · April 2015

@lowjack For my work, parametric Onshape will probably be the best tool ever made. And SW / Alibre will remain the second best. Just to be clear, with furniture I meant cabinets, drawers, office equipment - everything that's based on flat panels. I'm sure you had something 'softer' in mind.

@Andrew_Troup You might be right, in Finnish word furniture means the same as in English (by dictionary) - but what you actually think when using the word might be very different. We divide basically in two categories soft and hard - and I'm in the hard side. The easiest global term would probably be 'Ikea type flat-pack furniture'.
And as the clever ones already picked up between the lines, I'm not even close to native English speaker. Thanks for the complements though.

Unknown · April 2015

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ross · April 2015

Jon Banquer said:

The real reason we need parametric modeling is because no one has developed a user interface that makes direct modeling work well with family of parts. SpaceClaim might have been able to do it if they didn't run out of money because their marketing sucked and they kept changing their marketing plan. SpaceClaim had the right developer in David Taylor who is now developing CADstack which is cloud based CAD.

http://www.cadstack.com/

If we can't develop a better user interface for direct modeling we probably should accept that we need both parametric and quality direct modeling in one CADCAM product. I don't think very much of direct modeling that tacks on direct edits at the end of a history tree like Onshape and others do. I think doing this is very poor modeling practice. Direct edits should be local.

I've tried Onshape's direct modeling. I don't think it's very good and I don't see it as innovative.

Jon Banquer
CADCAM Technology Leaders group on LinkedIn

Jon you have got my vote. Do you have any idea at what point of gestation CADstack is at?

In the meanwhile I'll keep on using SpaceClaim.

Unknown · April 2015

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onshaper · April 2015

I'm still very confused as to why Direct Modelling has been said to be dimensionless and only for sculptural parts. SE Synch is phenomenal for machine design. Everything is dimensioned with PMI style 3d driving dimensions and 3d constraints. @lowjack it sounds like the parts you do are ideal for a good direct modeling environment.

As for Onshape's tools; it's JUST enough so you can make basic changes to imported geometry.

And that's the thing about DM. I can import geometry from any program into SE:Synch and edit it because no history tree is required.

And as for parasolid being parametric... not quite. SE:Synch is Parasolid kernal.

Unknown · April 2015

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onshaper · April 2015

Some seem to think that the Parasolid kernel means parametric modeling. SE is using the Parasolid kernel and has an excellent DM modeling environment. Instead of getting into it, I just wanted to present that you can have the Parasolid kernal and direct modeling, meaning that Onshape could conceivably go down this road in the future.

lowjack · April 2015

@Onshaper - I don't have any real criticism of direct modelling one way or the other, I've spent precious little time working in a direct modelling environment, so I am hardly qualified to offer an opinion on how great it is. My criticism here was the topic itself - Onshape is advertised and sold as a parametric modeler, so why does anyone use it and expect it to be a direct modeler? I don't buy coffee and complain because it doesn't taste like beer, or buy a pickup truck and wish it did a better job as a station wagon.

If Onshape can build direct modeling into the package successfully, great. I'd look forward to getting my feet wet in that area.

onshaper · April 2015

I think Parametric modeling is really quite good. It would be hard for me to say Onshape should put effort into a DM environment, as that would take resources away from their parametric efforts which have been really excellent so far. I do wish that Onshape had started DM because I'm more of a DM fan and if their effort was put into DM from the beginning I can only imagine how excellent it would be moving forward! At the end of the day it's kind of a wash, but DM is really intoxicating when you realize that you're just working geometry, not a history tree.

3dcad · April 2015

Just out of curiousity, in DM:
- Can you do pattern/mirror and come back to edit in same dialog?
- Can you set relations to dimensions ie. D3 = D1+D2?
- Can you have global parameters or spreadsheet driven designs?
- Can you have configurations (where difference typically would be different parameters and having some features suppressed)?
- Can you have named dimensions and show them in BOM?

Forget the Parametry

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