A randomly started discussion about the necessity of the PD single solid rule

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Syres
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by Syres »

wsteffe wrote: Thu Mar 23, 2023 3:19 pm I think that Part WB is more limited than PD.
I do not see a reason to maintain the separation between Part and PD.
I use Part Wb everyday and Part Design only for testing, for me Part Wb just suits the way I work and as Wandererfan says they both have their place.
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by -alex- »

wsteffe wrote: Thu Mar 23, 2023 3:19 pm Part wb should be suppressed. I do not see a reason to maintain the separation between Part and PD.
Part WB is less user friendly than PD (for holes for eg.), but it is far less CPU consuming compare to PD WB.
Part WB should not be suppressed, very useful on small embedded systems like Raspberry PI 4 :roll:
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by wsteffe »

wandererfan wrote: Thu Mar 23, 2023 3:38 pm They implement different modelling paradigms. As it was explained to me, Part is largely Composite Solid Generation modelling (think TinkerCAD?) and PD is feature history modelling.
Ok. But this confirms to me that it is not correct to say: "you may use Part as a replacement of RT version of PD (in which you may have many solids in a single Body)".
I want more solids in a Container but I want also keep using the feature history modelling which I am used to.
Last edited by wsteffe on Thu Mar 23, 2023 4:07 pm, edited 1 time in total.
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by user1234 »

wandererfan wrote: Thu Mar 23, 2023 3:38 pm
wsteffe wrote: Thu Mar 23, 2023 3:19 pm I do not see a reason to maintain the separation between Part and PD.
They implement different modelling paradigms. As it was explained to me, Part is largely Composite Solid Generation modelling (think TinkerCAD?) and PD is feature history modelling.

Both have their place.
Absoultly! And it is also a type of way of thinking while modeling. There are people out there, they only learned it in one way. Also there are some types of construction, where one way is better then the other. In a perfect world in a perfect CAD, there will be for CSG (Constructive Solid Geometry, PartWB) or FE (Feature Editing, PartDesignWB) all operation 2 times available, to do it in both ways.


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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by wsteffe »

wandererfan wrote: Thu Mar 23, 2023 3:32 pm Just to clarify, strictly speaking, a Body is not a container. It is the result of a series of (sketch based) operations.
For sure in the RT Branch (but I think also in Master) this is not correct.
The result of a series of (sketch based) operations is just a feature in the Body Container.
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by user1234 »

wandererfan wrote: Thu Mar 23, 2023 3:27 pm As I recall, when Part Design Next was being developed, the "rule" was implemented because creating multiple solids in one PD operation would cause subsequent operations to break or give incorrect results.
This is also what i remember. And partly it is true.


Since FreeCAD the naming generally works better and the TNP solution seems to slowly come into FreeCAD, it seems that rule can be dismissed. Also, in my humble opinion, this is in hand of the user and there are many workflows in PartDesgin (FE) where a multiple solids are needed, or at at least much better handled, even with the TNP.



wsteffe wrote: Thu Mar 23, 2023 4:12 pm The result of a series of (sketch based) operations is just a feature in the Body Container.
I think, it is is meant how FreeCAD works, internally it is no Container. From a users view, it looks like a Container,



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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by onekk »

wsteffe wrote: Thu Mar 23, 2023 3:19 pm ...
I do not see a reason to maintain the separation between Part and PD.

Part Design Wb is not following a modelling paradigm.

That from what I know are two:

- CSG Constructive Solid Geometry
- BREP Boundary Representation

Part WB can do both of them, plus Part WB is tightly related to "Part module" that is the core of FreeCAD as it is the interface to OCCT.

Part Design WB is following something more philosophical or to better say it is a "workflow that you must follow" and conform with, with many shortcut to make things, that on some extend are limiting "your modelling workflow" to those admitted by the "feature driven" way of doing things.

However a "Part WB NG" probably will be a viable way, but some thinking have to be done first to find a viable name for the new concept of modelling using a more BREP taylored workflow, but to make this jump, probably something has to be done to integrate some good tools to make BSpLineSurfaces or other more complex things, like Gordon Surfaces, Coons Surfaces, or more advanced ones, and to do some work on approximating a point cloud maybe obtained by automatic means (LIDAR or 3d Scanner) to obtain a smooth surface, to do so various smoothing algorithm should be integrated.

There are already many things done but they are scattered around in various WB like the notable "Curves WB" but even "Curved Shapes WB", and "Reverse Engineering WB"

Whatever way FreeCAD developers will follow is good for me as I made most of my works with scripting, so it is not a big hassle in my daily work, to be almost perfect some refinement in the interface and some more Python methods will be desirable, but as in actual state I have not much to complain about FreeCAD.

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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by wsteffe »

user1234 wrote: Thu Mar 23, 2023 4:18 pm I think, it is is meant how FreeCAD works, internally it is no Container. From a users view, it looks like a Container,
But also internally: for sure in the PD of RT the set of solids placed in a Body must be implemented as TopoDS::Compound.

And
wandererfan wrote: Thu Mar 23, 2023 3:32 pm A Compound could also be considered a container.
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by user1234 »

wsteffe wrote: Thu Mar 23, 2023 4:31 pm for sure in the PD of RT
And is it in the master?
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Re: A randomly started discussion about the necessity of the PD single solid rule

Post by wsteffe »

user1234 wrote: Thu Mar 23, 2023 4:07 pm In a perfect world in a perfect CAD, there will be for CSG (Constructive Solid Geometry, PartWB) or FE (Feature Editing, PartDesignWB) all operation 2 times available, to do it in both ways
Agreed. But in the RT branch both modelling are available in the same PD WB.
In fact he has ported to PD the primitive geometries (Box, Cylinder, Sphere, Cone, Ellipsoid, Torus ...) and the boolean operations.

So what would you miss to allow CSG kind of modelling in PD ?
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