Parametric modelled Vs Direct modelled Vs Synchronous technology

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dcapeletti
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Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by dcapeletti »

Hi, let me open a discussion on 3D modeling technologies.
Parametric modeling has long been the forerunner of several programs used in the industry. But I have been looking at some sites and researching about other modeling techniques or technologies and it seems to me that parametric modeling as we know it, seems to be obsolete in the future because history-based design seems to be too strict for certain designs, because it is delicate to modify functions in the middle of history because you can break the model if you don't understand well its algorithms or its history.

Talking about freecad, specially the part desing workbench is focused on parametric design, but I think you can create another direct modeling bench from the part desing bench because it works with primitives, that is, this bench designers can press and pull their model to change it. One advantage of this capability is the ease with which designs can be modified, allowing for rapid iteration and prototyping. The ability to change a model without worrying about breaking it can mean a lot.

Even better could be the hybrid design combination of parametric and direct modeling. It could be a combination of part, part design, draft and other tools.

Here I leave you with a series of interesting articles to read.

https://www.engineering.com/DesignSoftw ... eling.aspx
https://www.smlease.com/entries/cad/typ ... -modeling/
https://www.youtube.com/watch?v=LpkkXuesUGs

I hope your comments and why not, the motivation for programmers and designers to go for the creation of hybrid combination workbenches.

Greetings ;)
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by drmacro »

dcapeletti wrote: Sat Aug 29, 2020 12:01 pm ...
Well, I'm a veteran of the CAD wars since the 1970's. I can say this is not a new discussion. ;)

Obviously the user paradigm for the two workflows is different.

Blender could be considered a direct modeler. There are those who do mechanical designs in Blender. But the UI is not tuned for mechanical design. There is, in fact, no reason it couldn't be. But, as noted in the articles, direct design is well suited for dumb model formats (step/IGES, etc.) with no memory of what process was used to create the current shape. This will be great when we finally get to the holy grail of "cradle to grave" manufacturing, for example when manufacturing techniques like 3D printing and multi-axis machining is the norm. (Think Star Trek replicators.)

It may difficult (though strictly conjecture on my part) to create a direct model UI with the current underpinnings of FreeCAD. (I'm guessing OCC just doesn't work this way...again conjecture on my part...)

Knowing both FreeCAD and Blender, I use whichever one I deem is the best choice for the task at hand. For example, I'd design a curvy body panel for a car in Blender, then export it to FreeCAD to add mounting brackets to attach it to the chassis which would be better designed in FreeCAD.

It's not hard to imagine an Blender workbench in FreeCAD... ;)
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by carlopav »

Hope this is on topic (also if this is a bit of a cross-post i think). Here are some experiments on non parametric shape editing with Draft subelements move. Perhaps could be an interesting suggestion to make a dedicated "parametric" DirectEdit DraftObject or PartDesign Feature out of it...


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dcapeletti
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by dcapeletti »

Very interesting is the example of direct editing. It would be appropriate to have some workbench to design pieces under direct editing. I think that combining part, draft could be achieved. I hope there are several interested in this type of modeling.

Greetings
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by carlopav »

Ok, so also this PR should be on topic: it provides the infrastructure to use Draft Edit command on every object. Much thanks to @vanuan and @vocx for pointing the right direction.
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by thomas-neemann »

I created a video which, in my opinion, is parametric, the input field can even "named references".


https://www.youtube.com/watch?v=uvZZkAJSDYE


phpBB [video]
Last edited by thomas-neemann on Fri Jun 11, 2021 3:46 pm, edited 1 time in total.
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by Kunda1 »

Design456 workbench aims to fill this [Direct modeling] niche.
https://github.com/MariwanJ/Design456
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by thomas-neemann »

Kunda1 wrote: Wed Mar 10, 2021 12:34 pm
thanks for the information. the first impression is very good
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igormedeiros
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by igormedeiros »

Kunda1 wrote: Wed Mar 10, 2021 12:34 pm Design456 workbench aims to fill this [Direct modeling] niche.
https://github.com/MariwanJ/Design456
Hello Everyone. Excellent Day!

It is very impressive mod. The synchronous modeling and direct modeling improve the modeling tasks and allow quick jobs. Move a face, replace a face, pull a face, delete a face, offset face are very good tools in this technology.

I really appreciate this link Kunda1. And if there another one project that involves direct modeling and synchronous modeling let me know.
I am still working on compile/build of freecad in my PC. So, today I will finish the thirdy-part libs install and let's see whats happen.. :D :D


Thank you so much.


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drmacro
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Re: Parametric modelled Vs Direct modelled Vs Synchronous technology

Post by drmacro »

I appreciate that this "direct modelling" may be fast(er).

But, IMO, it is designed for "seat of the pants" design or artsy work. Blender is designed primarily for artists and will allow things like dragging faces, rings of faces, etc., basically on the fly sculpting.

I see these techniques a a recipe for creating models that are hard to follow, maintain, and fragile.

I'm happy to be proven wrong in the long run...but that's how I see it. :mrgreen:
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
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