Sweden is Having a Sweeping Problem

[Mr Wahlander]

… if you still want to do it by PartWB-sweep here is some kind of testcase:
Working with 2 BSpline-sketches for profiles, copying and turning them around Z-Axis by relative placement.
(Caution: most of the bspline points are gridsnapped - I was in hurry)
The sweeppath is also a sketcher-BSpline.
And it is better to position the sweeppath on the "inside track" - no overlap or loops!


Walander_2.PNG

Thank you Hammax, this would work!
I would be most grateful for a few clarifications. I'm learning...
Questions:
• "turning them around Z-Axis by relative placement" How do you do that?
• I took away 4e of your sketches, altered the remaining and added a new 90 degree. Now it looks ridiculous..
• Whats the trick with the angles (I guess that's how you produce smooth surface?)
• no overlaps (?) no overlaps with the sweep path? ...

Johan

[microelly2]

I had some fun this afternoon to get the model with 3 sketches
still some debugging and clean up needed
but this is the "one face" BSpline surface

the result

bp_837.png (416.06 KiB) Viewed 897 times

and the sketches

bp_838.png (187.12 KiB) Viewed 897 times

[Mr Wahlander]

I had some fun this afternoon to get the model with 3 sketches
still some debugging and clean up needed
but this is the "one face" BSpline surface

the result
bp_837.png
and the sketches
bp_838.png

Nice hat!
I tried to copy from you, and made this – still awful.
Are we using the same sweep-tool?
Is there a way of making the sweep stop at the first and last "rib"
what'a the logic behind the angles of your datum planes? And how did you come up with the numbers... :-/

thank you so much for the input, I feel I'm on to something that could work.
!
Johan

[hammax]

… the experienced use of Placement is next to Sketcher and PartWB one of the basic skills in FreeCAD. (my opinion).
Loops, twists and overlaps of the resulting shell are a sign for profiles arranged with wrong turning cycle (or erratic FC).
Try Sketcher BSplines and become a friend of them…. (they are new - ellipses are old stuff and sometimes tricky)

Walander_6.PNG (74.7 KiB) Viewed 866 times

[freecad-heini-1]

I had some fun this afternoon to get the model with 3 sketches
still some debugging and clean up needed
but this is the "one face" BSpline surface

the result
bp_837.png
and the sketches
bp_838.png

Hi Thomas,
thank you so much for this bavarian hat.
Please can you try to use the original curves to create the Gordon face. That would be very nice.
https://forum.freecadweb.org/download/file.php?id=63579
Best regards
Wilfried

[hammax]

...cloudy Sunday morning; training FC skills on Chris_G's CurvesWB.
BSplines fully constrained for the birails and profiles. Both from a startersketch with duplicate selection and placement round Z.
PartWB face between the birail sketches.
Sweep_2_rails with the birail surface and the 3 profiles.
Approximation_Curve on Sweep_2_rails. Always look for the parameters in view- and data-tab.

FC.18.14090

Walander_7.PNG (72.74 KiB) Viewed 846 times

[Mr Wahlander]

...a sign for profiles arranged with wrong turning cycle (or erratic FC).
..

Walander_6.PNG

You, the maker of Bavarian hats.
Thank you so much for your patience with a beginner!
I now know a lot of stuff that I didn't know before.

I have tried to figure out what a "wrong turning cycle" might be.
I am guessing that B-splines, and such, have a start and an end? This is of course wrong, and I have looked in the documentation...

:-/

[microelly2]

Please can you try to use the original curves to create the Gordon face. That would be very nice.
https://forum.freecadweb.org/download/file.php?id=63579

here is my solution
the main problem with gordon surface in this case is that the curves have different numbers of knots and the position of the knots is essential
for the layout of the surface, so Ihave to insert same knots.
I made this in different positions to demonstrate the impact of the locations of the knots.
For the real usecase you will use the same knot vector on all sides.

https://www.dropbox.com/s/9twmt4c1ywpu0 ... fcstd?dl=0

phpBB [video]

[freecad-heini-1]

Thank you so much Thomas. Very nice to see these great tools in your Nurbs workbench.

What about if you change corner break to false from the curves-wb joincurve?

joincurve_corner-break_false.png (20.47 KiB) Viewed 811 times

[microelly2]

Thank you so much Thomas. Very nice to see these great tools in your Nurbs workbench.

What about if you change corner break to false from the curves-wb joincurve?
joincurve_corner-break_false.png

thank you, works fine.