[Feature Request] 3D sketches
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[Feature Request] 3D sketches
Hi,
I think that the possibility to create 3D sketches in FreeCAD could be very useful. For me, the main use would be to create geometries for 3D frame and truss analyses in FEM module or external FEA software. But there are also other potential applications - mainly drawing paths for sweeps and creating lines to which weldment profiles can be applied (it's a common way of constructing frames in other CADs). Potentially also pipeline, duct and cabling design could benefit from this feature (not my area of work though).
I know that Draft Workbench allows for 3D drawings but they can't be converted to sketches and thus can't be used for the aforementioned operations. Maybe it's not necessary to introduce a whole new feature for 3D sketches and just an improvement to the existing Draft Workbench functionality (allowing for the conversion of 3D drawings to sketches) would be enough.
What are your thoughts on this topic ?
I think that the possibility to create 3D sketches in FreeCAD could be very useful. For me, the main use would be to create geometries for 3D frame and truss analyses in FEM module or external FEA software. But there are also other potential applications - mainly drawing paths for sweeps and creating lines to which weldment profiles can be applied (it's a common way of constructing frames in other CADs). Potentially also pipeline, duct and cabling design could benefit from this feature (not my area of work though).
I know that Draft Workbench allows for 3D drawings but they can't be converted to sketches and thus can't be used for the aforementioned operations. Maybe it's not necessary to introduce a whole new feature for 3D sketches and just an improvement to the existing Draft Workbench functionality (allowing for the conversion of 3D drawings to sketches) would be enough.
What are your thoughts on this topic ?
Re: [Feature Request] 3D sketches
Have you use the Draft workbench?
You can draw lines in 3D space.
As for the Sketcher, I think you misunderstand the paradigm. For example, the concept is to draw a cross section of the shape and give it depth (the 3rd dimension).
To me it is actually far simpler to imagine the length and width, then apply a depth.
You can draw lines in 3D space.
As for the Sketcher, I think you misunderstand the paradigm. For example, the concept is to draw a cross section of the shape and give it depth (the 3rd dimension).
To me it is actually far simpler to imagine the length and width, then apply a depth.
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
Re: [Feature Request] 3D sketches
Yes, I’ve already tested drawing 3D lines in Draft Workbench. It’s quite good functionality but 3D lines drawn there can’t be used for sweeps and most likely for other purposes mentioned in my previous post (please correct me if I’m wrong).
Re: [Feature Request] 3D sketches
Hmm...a 3D rectangle created in Draft WB, Extruded in Part WB:
Or, how about a Loft?:
Or, how about a Loft?:
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
Re: [Feature Request] 3D sketches
3D sketches? for what?
Each CAD system has his underlying paradigm, almost always this paradigm is related to the 3D engine, which have to do the "hard work".
FreeCAD has it's 3D engine (modeler or what do you want to call it).
His base paradigm to draw in 3D his to create Vertex, Edges, and Faces.
so having a 3D sketch would mean to have a way to define Vertexes that create edges and make faces, in 3D space.
A "3D sketch" to make a cube has to define eight vertexes, for complex things, you have to define maybe curves in 2D space, properly orient them and then limit this curves to form edges (boundary of faces) and join them.
A Sketch generally is a 2D drawing, you could define constraints, to make a sketch work and maybe when modifying the shape some elements are automagically recalculated.
see:
https://wiki.freecadweb.org/Sketcher_SketchObject
But in 3D such constraints are more complex, sometimes have no sense to define maybe a perpendicular constraint for a face that could be modified if a vertex is moved.
I don't know how other CAD solve these problems, but "simply" adopting a way to model is not everytime a "simple" solution if the underlying modelling engine is different.
Sadly there is no a proper wiki page to illustrate the modelling paradigm:
In FreeCAD you have the ability to use both CSG and BREP see wikipedia for more explanation, (not a scientific approach, but for having an idea it will suffice).
See however:
https://wiki.freecadweb.org/Getting_started/en
https://wiki.freecadweb.org/Part_TopoShape
https://wiki.freecadweb.org/App_DocumentObject
And more general:
https://wiki.freecadweb.org/OpenCASCADE/en
https://dev.opencascade.org/doc/occt-7. ... _data.html
To have an idea of "how things works".
This discussion has been done many times, but in general the answer is:
FreeCAD has his own way to do things, and using another modeling paradigm is difficult to implement and lead to many "assumptions" and overcomplications so better to learn the FreeCAD way than mimic the behaviour of some other program that maybe could bring to copyright infringments.
Hope it helps
Regards
Carlo D.
Each CAD system has his underlying paradigm, almost always this paradigm is related to the 3D engine, which have to do the "hard work".
FreeCAD has it's 3D engine (modeler or what do you want to call it).
His base paradigm to draw in 3D his to create Vertex, Edges, and Faces.
so having a 3D sketch would mean to have a way to define Vertexes that create edges and make faces, in 3D space.
A "3D sketch" to make a cube has to define eight vertexes, for complex things, you have to define maybe curves in 2D space, properly orient them and then limit this curves to form edges (boundary of faces) and join them.
A Sketch generally is a 2D drawing, you could define constraints, to make a sketch work and maybe when modifying the shape some elements are automagically recalculated.
see:
https://wiki.freecadweb.org/Sketcher_SketchObject
But in 3D such constraints are more complex, sometimes have no sense to define maybe a perpendicular constraint for a face that could be modified if a vertex is moved.
I don't know how other CAD solve these problems, but "simply" adopting a way to model is not everytime a "simple" solution if the underlying modelling engine is different.
Sadly there is no a proper wiki page to illustrate the modelling paradigm:
In FreeCAD you have the ability to use both CSG and BREP see wikipedia for more explanation, (not a scientific approach, but for having an idea it will suffice).
See however:
https://wiki.freecadweb.org/Getting_started/en
https://wiki.freecadweb.org/Part_TopoShape
https://wiki.freecadweb.org/App_DocumentObject
And more general:
https://wiki.freecadweb.org/OpenCASCADE/en
https://dev.opencascade.org/doc/occt-7. ... _data.html
To have an idea of "how things works".
This discussion has been done many times, but in general the answer is:
FreeCAD has his own way to do things, and using another modeling paradigm is difficult to implement and lead to many "assumptions" and overcomplications so better to learn the FreeCAD way than mimic the behaviour of some other program that maybe could bring to copyright infringments.
Hope it helps
Regards
Carlo D.
GitHub page: https://github.com/onekk/freecad-doc.
- In deep articles on FreeCAD.
- Learning how to model with scripting.
- Various other stuffs.
Blog: https://okkmkblog.wordpress.com/
- In deep articles on FreeCAD.
- Learning how to model with scripting.
- Various other stuffs.
Blog: https://okkmkblog.wordpress.com/
Re: [Feature Request] 3D sketches
Thanks for replies. It seems that it's actually possible to use the 3D lines created in Draft Workbench for spatial frame analysis (done internally or externally). I just had to apply boolean union from Part Workbench to those lines.
However, I wonder what is your way of modeling parts that are normally designed using sweep with 3D path. Here are some examples:
https://help.autodesk.com/cloudhelp/201 ... 24420D.png
https://www.cadtutor.net/forum/uploads/ ... 81de56.jpg
https://dddmodeling.files.wordpress.com ... =981&h=530
https://i.pinimg.com/564x/45/a0/ee/45a0 ... 730f98.jpg
Is it doable in FreeCAD ?
However, I wonder what is your way of modeling parts that are normally designed using sweep with 3D path. Here are some examples:
https://help.autodesk.com/cloudhelp/201 ... 24420D.png
https://www.cadtutor.net/forum/uploads/ ... 81de56.jpg
https://dddmodeling.files.wordpress.com ... =981&h=530
https://i.pinimg.com/564x/45/a0/ee/45a0 ... 730f98.jpg
Is it doable in FreeCAD ?
Re: [Feature Request] 3D sketches
Good question about 3D curves and sweep.
I noticed that the Part and Part Design WB do not like mixing Sketcher WB and Curve WB paths
I noticed that the Part and Part Design WB do not like mixing Sketcher WB and Curve WB paths
MacOS Big Sur / Win 10
Designer | Faculty
Wayne State University
Interior - Industrial Design
Designer | Faculty
Wayne State University
Interior - Industrial Design
Re: [Feature Request] 3D sketches
All of these can be done:NewJoker wrote: ↑Tue Aug 03, 2021 5:13 pm https://help.autodesk.com/cloudhelp/201 ... 24420D.png
https://www.cadtutor.net/forum/uploads/ ... 81de56.jpg
https://dddmodeling.files.wordpress.com ... =981&h=530
https://i.pinimg.com/564x/45/a0/ee/45a0 ... 730f98.jpg
Is it doable in FreeCAD ?
1) addon macro 3D parametric curve, or perhaps even helix (not quite clear from the image)
2), 4), see e.g. "Wilfried's trick": https://forum.freecadweb.org/viewtopic. ... 45#p165745
3) Helix, Arrays
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
Re: [Feature Request] 3D sketches
Star Trek II: The Wrath of Khan: Spock: "...His pattern indicates two-dimensional thinking."
Re: [Feature Request] 3D sketches
Thank you guys, that's really informative. I wonder why macros like the one for parametric curves don't get implemented into FreeCAD. It shouldn't be difficult and it's better to have more built-in functions.
I tried performing a sweep along 3D path created by applying boolean union to 2 separate 2D sketches:
The result is wrong when I use Part Design sweep:
But it's fine when Part sweep is used:
Merging 2D sketches seems to work but it would be easier with 3D sketches like those offered by Draft Workbench.
I tried performing a sweep along 3D path created by applying boolean union to 2 separate 2D sketches:
The result is wrong when I use Part Design sweep:
But it's fine when Part sweep is used:
Merging 2D sketches seems to work but it would be easier with 3D sketches like those offered by Draft Workbench.