[Feature request] Loft improvement - PartDesign

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Pauvres_honteux
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[Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Tue Aug 13, 2019 10:34 am

Pipe_test_2_b.png
Pipe_test_2_b.png (44.39 KiB) Viewed 1155 times
BlendCurve is discussed here: BlendCurve discussion
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My wishes:
- function for coupling/selecting point-to-point between sketches (controlling what connects to what).
- force the loft to accept the BlendCurve as a spine.
- force the loft start/end to be tangent/curvature correct to a surface (not seen in the picture) connected to each sketch at each end of the sweep.
- force the loft to be tangent/curvature correct to surfaces (not seen in the picture) connected to each sketch section along the sweep.
- GUI visible vectors per connection point, to visually confirm everything goes in intended direction and doesn't create a surface kink. This includes the sketches.
- GUI preview of the surface (separate sandbox/window?)
- double clicking on the finished loft surface brings up the same window again.
- An overhaul of today's GUI. See inspiration from CATIA. It aint pretty but it works and it's logical and I'm confident we can come up with something prettier and less "click prone".
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Pipe_test_2_c.png
Pipe_test_2_c.png (155.16 KiB) Viewed 1155 times
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saso
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Re: [Feature request] Loft improvement - PartDesign

Postby saso » Tue Aug 13, 2019 2:08 pm

I wonder what are you actually trying to do... Do you have your tree set up the way you have it because you really want to have it this way or just because it looks to you similar to what you are maybe used to in Catia?

First in FreeCAD you should probably use the sweep for this (if you absolutely want to work with FreeCAD part design and body, if not, there is also Part sweep and Curves PipeShell), it allows you to pick a path and set one or more sections for it, this would then already check off at least one of your wishes :)

Second, here is how this tree that you have here in FreeCAD would actually look like in Catia:
- you would have an assembly and four parts in it
- in the body of part one you would have what you have in "Body"
- in the body of part two you would have what you have in "Body001"
- in a geometrical set (or a hybrid body) of part three you would have those objects that you have between Body001 and Body002, Link_to_DatumPointXXX would be "past special result with link" of points from part one and part two
- and in part four you would have again some "past special result with link" of objects from part three and the multi-section solid from it
(PS: I don't know if this would actually all work in Catia, but I promise you, from a correct analogy of objects and tree structure this is how this would look in Catia)

Is this what you actually want to have?! Or would you do this in Catia all in one part with multiple bodies and/or geometrical sets? As I said many times before FreeCAD bodies are implemented wrongly, don't get confused by the name, if you write chicken on a cow it is still not a chicken, FreeCAD Bodies are actually "special" limited parts, same as if you would have in Catia a special type of a part where you would be able to have inside of it only one body and be able to use in it only the tools from Catia part design. And this is wrong, and this is why they should be fixed. Proper bodies don't have their own origin, all the objects inside the body still references back to the origin of its part.

If what you want is actually to have like a single part, then my best suggestion, at least for now is to move everything out of the bodies and try to use other workbenches instead of the part design (if you want just solids with ordered features set then part design is fine), in this topic you will find a link to a model that shows some of the possibilities that IMO work quite ok https://forum.freecadweb.org/viewtopic.php?f=8&t=38388

We could talk a bit more about some of your wishes but in general they are good, however I don't see much sense in improving this (and similar things) before some much more fundamental things get fixed and improved in FreeCAD first. I still stand by the suggestions I made here https://forum.freecadweb.org/viewtopic. ... 10#p320885
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Pauvres_honteux
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Re: [Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Wed Aug 14, 2019 8:36 am

saso wrote:
Tue Aug 13, 2019 2:08 pm
First in FreeCAD you should probably use the sweep for this...
Easy now! Please reread this post headline!!!
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saso wrote:
Tue Aug 13, 2019 2:08 pm
... if not, there is also ... Curves PipeShell), it allows you to pick a path and set one or more sections for it, this would then already check off at least one of your wishes :)
My updated FreeCAD just made Curves crashing... ooh well, what's a ball at the castle anyway?
Perhaps you could show a fully working, linked and parametric, lofted surface here. Where the user can select point inter connectivity. Attaching a file to play with:
Pipe_test_2.FCStd
(62.01 KiB) Downloaded 28 times
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saso wrote:
Tue Aug 13, 2019 2:08 pm
... FreeCAD Bodies are actually "special" limited parts... And this is wrong, and this is why they should be fixed. Proper bodies don't have their own origin, all the objects inside the body still references back to the origin of its part.
I've discussed this with @realthunder and he promised to have a look at it since, as you type, the whole concept is one level off. At the very least designation wise.
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saso wrote:
Tue Aug 13, 2019 2:08 pm
We could talk a bit more about some of your wishes...
Indeed the very purpose of this thread...
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saso wrote:
Tue Aug 13, 2019 2:08 pm
I still stand by the suggestions I made here https://forum.freecadweb.org/viewtopic. ... 10#p320885
Fair enough and I generally agree, be it in another order, but agree I do.
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Pauvres_honteux
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Re: [Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Mon Oct 14, 2019 7:11 pm

For the interested ; this is how it's done in CATIA:
Tubes_in_spaaace_1.pdf
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Tubes_in_spaaace_2.pdf
(381.05 KiB) Downloaded 29 times
Tubes_in_spaaace_3.pdf
(813.59 KiB) Downloaded 31 times
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GlouGlou
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Re: [Feature request] Loft improvement - PartDesign

Postby GlouGlou » Mon Oct 14, 2019 8:17 pm

Pipe test through a standard workflow.
The blend curve is 3rd degree limited, otherwise freecad freeze.
Could be made with bodies as well.
Attachments
Capture.PNG
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essai.FCStd
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Re: [Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Wed Oct 16, 2019 6:49 pm

I tried to manipulate your model @GlouGlou, but my FreeCAD got into an infinite loop / hanged.
On top of that the surfaces have kinks -> it's a no-go workflow.
And finally: this topic is about Loft improvement. One can also denote it multi section surfaces.

The only way to make an advanced tube surface is make it with the principle workflow showed in the earlier attached pdf's.
To make that workflow work we must first have the points, lines and planes creation working, see [Feature requests] Working points, lines and planes

PS. This is just the very basics of creating an exhaust gas manifold or some automotive in cab AC air distribution tubes. Or an A-pillar or ...
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GlouGlou
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Re: [Feature request] Loft improvement - PartDesign

Postby GlouGlou » Wed Oct 16, 2019 7:24 pm

Yours pdfs seem to require great effort to carry out a nice surface, but are very interesting. ;)
Pauvres_honteux wrote:
Wed Oct 16, 2019 6:49 pm
I tried to manipulate your model @GlouGlou, but my FreeCAD got into an infinite loop / hanged.
It crash because the path is very sharpy and too small, I guess. The surface is near to intersect it self.
Attachments
essai2.FCStd
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GlouGlou
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Re: [Feature request] Loft improvement - PartDesign

Postby GlouGlou » Thu Oct 17, 2019 6:38 pm

Something like this. :)
Attachments
CatiaPipe.FCStd
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Capture.PNG
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Re: [Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Sun Oct 20, 2019 9:31 am

How to force it to follow your profile?
How to force it to be tangent to the other surfaces?
Tube_tangency.png
Tube_tangency.png (87.81 KiB) Viewed 684 times
I see you heavily utilize approximations in your design. To what degree does that correspond to the original straight line or curve?
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Plane_position.png
Plane_position.png (80.84 KiB) Viewed 684 times
The point that is supposed to rule the plane position along the Blend_Curve (aka Main curve). I can not find that point or see how you force it to follow the Blend_Curve (aka Main curve)?
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Re: [Feature request] Loft improvement - PartDesign

Postby Pauvres_honteux » Sun Oct 20, 2019 9:38 am

I made a small part of the tube in catia and exported it as a stp-file with different languages. Of course catia made everything stone dead...
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Surface_Loft_std.stp
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anyway, you who read this get the idea.