Failure after failure trying to create a funnel shape. Please, help! Thanks

[wisecad]

Dear FreeCAD team/community,

- Introduction (you can skip this detail and go directly to the problem section):
Please, see below the object I am trying to model, which for this illustration I have created using another 3D-modeling software package that shall not be named.

Software-Freecad-Issues-11-Funnel-01.jpg (45.87 KiB) Viewed 1020 times

So far, I have got the bottom part of the object, as seen in the image below, but I am missing the top funnel shape.

Software-Freecad-Issues-11-Funnel-01b.jpg (54.5 KiB) Viewed 1020 times

Problem: To get a funnel shape on top of the tubular structure (that emerges from the base), I have tried the following unsuccessful strategies.

Strategy-1: On the top circular face of the wider tubular structure atop the base, add a sketch with two concentric circles, then change the view tab’s Attachment-Offset’s Position (on the z-axis to elevate it a little over the structure), and finally pad (using the Part-Design workbench) the outer circle to get the funnel’s top narrow tube. Afterwards, I would link both (the wider and the narrow) tubular structures using a loft.
Please, see the image below as the model looks in the preliminary stage, right before I try to apply the pad tool on the outer circle of my new sketch.

Software-Freecad-Issues-11-Funnel-04.jpg (56.8 KiB) Viewed 1020 times

Result: Failure. Didn't even get to try to link the wider and the narrow tubular structures using a loft.
Got the following error message: “Pad: Result has multiple solids. This is not supported at this time.”
Even thou on a brand new document I am able to add a sketch with two concentric circles, then pad the outer circle to get a tubular shape (like the funnel’s top narrow tube I desire). Please, see the animated image below. When I try to do the same thing in my existing model, I get the error described above.

Software-Freecad-Issues-11-Funnel-03.gif (51.12 KiB) Viewed 1020 times

Strategy-2: Add the funnel’s top narrow tube using the Tube creation tool (in the Part workbench), then use a loft to link the narrow tube’s bottom face with the face on the wider tubular structure atop the base. Please, see the image below showing the two structures (the funnel’s top narrow tube and the wider tubular structure atop the base) that I am trying to bridge with a conic shape I was hoping to produce with the loft tool.

Software-Freecad-Issues-11-Funnel-02.jpg (88.79 KiB) Viewed 1020 times

Results: Double Failure
Failure 1: If I try to loft the narrow tube’s bottom face with the top circular face on the wider tubular structure atop the base I get the following error message: “Loft: Sections need to have the same amount of inner wires as the base section”
Failure-2: If I try to loft the narrow tube’s bottom face’s inner circle with the inner circle on the face of the wider tubular structure atop the base I get the following error message: “Linked shape object is not a wire”


Strategy-3: Pad (using the Part-Design workbench) the top circular face on the wider tubular structure atop the base, then scale the pad’s top circular face to narrow it, thus giving it a conic shape. Then use the pad tool again on the now scaled down face atop the conic shape to extend it, thus creating the narrow tube.
Result: Failure.
The entire tubular structure atop the base (not just the new pad’s top circular face as I intended) got scaled down. Even worse, it was a copy of the structure that got scaled down, not the referred structure itself.



QUESTION: Is there an easy way to produce the funnel on to of what I already have. It seems like conceptually I have the right ideas, but when it comes to execution I am horrible at guessing how FreeCAD is going to react to my commands. Maybe it is my previous experience using polygonal editors like Sketchup and Blender. Or maybe I am just plain stupid. I am leaning towards the last explanation,so I think I need a step-by-step guide.


Thanks in advance for your time and for your answers.

Cheers

Raoul

[drmacro]

you can't select faces of generated geometry and loft between them (at least in the main branch), but you can create face binders and loft them.

(not at a pc so can't offer an example ATM)

[wisecad]

you can't select faces of generated geometry and loft between them (at least in the main branch), but you can create face binders and loft them.

(not at a pc so can't offer an example ATM)

Hello DrMacro. Thanks for your suggestion.
After learning that facebinders existed and reading a bit about them, I created a facebinder for the circular face of the wider tubular structure atop the base, and another facebinder for the funnel's narrow tube’s bottom face. With the first facebinder selected, I clicked on the loft tool, only to get the following error message: "Cannot use selected object. Selected object must belong to the active body. Consider using a ShapeBinder or a BaseFeature to reference external geometry in a body"
Please, see the image below, showing the first facebinder I made (for the circular face of the wider tubular structure atop the base) selected and the error I got upon trying to use the loft tool.

Software-Freecad-Issues-11-Funnel-05.jpg (134.07 KiB) Viewed 993 times

[bambuko]

Why not use revolve for the funnel?
What am I missing?

see attached:

funnel.FCStd

(19.5 KiB) Downloaded 36 times

PS
btw - as far as I know you shouldn't be mixing Part with Part Design...

[drmacro]

Why not use revolve for the funnel?

probably a better option...

PS
btw - as far as I know you shouldn't be mixing Part with Part Design...

That's generally what is said to new users to avoid the gory details.

But, the more accurate sentence is: "You shouldn't mix Part and PartDesign until you understand the implications and pitfalls. "

[wisecad]

Why not use revolve for the funnel?
What am I missing?

see attached:
funnel.FCStd

PS
btw - as far as I know you shouldn't be mixing Part with Part Design...

Hello Bambuko, Thank you for your suggestion and for the sample file.
It makes perfect sense. Do to my inexperience, I thought the strategies I tried were less likely to give me problems, than something I had not even read about (the revolve tool) before. Thanks again.

Regarding not mixing Part with Part Design, that is news to me. Never heard of it. Thanks for the warning.

[wisecad]

That's generally what is said to new users to avoid the gory details.

But, the more accurate sentence is: "You shouldn't mix Part and PartDesign until you understand the implications and pitfalls. "

"gory details" You are scaring me

[fatbeard]

made with the partdesign workbench and lofting in mere minutes:

Screenshot from 2021-06-24 14-54-57.png (11.73 KiB) Viewed 914 times

[Shalmeneser]

The best solution is a Revolution.

Is your thickness constant ? (the same thickness = only one dimension in the sketch)
The dimensions are for the interior or the exterior ?

[wisecad]

made with the partdesign workbench and lofting in mere minutes:

Hello Fatbeard. Thank you so much for your sample file.
This is exactly what I had originally conceptualized, except I did not know how to implement it. I took your file, deleted the loft and re-built it myself to make sure I understood your construction. It was exactly as I thought. Very cool. Now I know how to do it. Thanks again.