Curves workbench

[Chris_G]

Sorry. that was the reason, after update all works fine.

No problem !

[hammax]

Hi Chris,
I made another attempt by projecting a semicircle on a sphere.
A lot of trial until it was on the right place and also some erratic results.
I am trying to evaluate a macro that produces a fiber winding pattern on a sphere.
E.g. light weight high pressure vessels. (Granny's wool ball - more regular).

My macro-algorithm delivers only tracks going through the poles until now.
But I am needing tracks with a controllable offset of the usual great-circle-path.
So I tried your Sketch_On_Surface in CurvesWB and compared it with macro results.
The magenta lines are from CurvesWB in some good position.
(But if I edit the arc "a little bit" to shorten the line ends , the figure changes overdone)
I need a defined section of it to produce and test pattering and placement operations.

SphereWrap_4.PNG (90.17 KiB) Viewed 2132 times

[Chris_G]

I made another attempt by projecting a semicircle on a sphere ...

Hi hammax,
I am not sure I understood what you want to do.
The Sketch_On_Surface tool should have its properties "Construction bounds" and "Scale" set to True (I think I should even remove these properties to avoid confusion) otherwise the result becomes pretty much unpredictable.
So, with "Construction bounds" and "Scale" set to True, the outer construction square of the sketch represents the topologic boundaries of the surface.
In your current example :

• the upper edge of the blue square is mapped to a single point (north pole)
• the lower edge of the blue square is mapped to a single point (south pole)
• the 2 side edges of the blue square get mapped to a single meridian (the seam of the sphere)

[hammax]

… your newest update to CurvesWB (normal and binormal faces) when projecting a curve on surface,
is the clue to my problem described above.
Trying to generate winding patterns on sphere I could produce a "roving" by using BSpline from a macro
on a sphere's surface with binormal and symmetric. (Otherwise I had to make a sketch for the profile and sweep it).
Same procedure with two "greatcircle-arcs" and a CurvesWB blendcurve (which doesn't exactly lay on the sphere)
but the projected Curve_on_Surface does. And this solution is parametric compared to the macro-draft-BSpline.
Fiber winding is rather a theme for CAM.
https://www.youtube.com/watch?v=tUrGZMB4WHY

FC.18.14090

SphereWrap_17.PNG (132.27 KiB) Viewed 1963 times

[hammax]

Hi Chris,
I did it! At last I could generate a diagonal winding-pattern for CFRP high pressure vessels
with geodesic arcs, blending Polynome and CurvesOnSurface. (on a PC with no commercial prog)...
(Is there an interest in a special thread? ) https://forum.freecadweb.org/viewtopic. ... 80#p212484

SphereWrap_18.FCStd

FC.18.14126

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[Chris_G]

Hi Chris,
I did it! At last I could generate a diagonal winding-pattern for CFRP high pressure vessels
with geodesic arcs, blending Polynome and CurvesOnSurface. (on a PC with no commercial prog)...
(Is there an interest in a special thread? ) https://forum.freecadweb.org/viewtopic. ... 80#p212484

Hi,
I had no precise idea of what are CFRP high pressure vessels, so I had a couple of interesting readings on the net.
Now, I understand the purpose.
Good job !

[triplus]

Nice!

[polymer]

Impressiv, but are simple things possible like a straight line from a Circle/Radius middpoint to another one? Like in a hole?

[microelly2]

Impressiv, but are simple things possible like a straight line from a Circle/Radius middpoint to another one? Like in a hole?

something like geodesic lines?
https://forum.freecadweb.org/viewtopic. ... 80#p211774
https://forum.freecadweb.org/viewtopic. ... &start=120

[polymer]

Impressiv, but are simple things possible like a straight line from a Circle/Radius middpoint to another one? Like in a hole?

something like geodesic lines?
https://forum.freecadweb.org/viewtopic. ... 80#p211774
https://forum.freecadweb.org/viewtopic. ... &start=120

Hmm, no.
I meant some basic stuff like this:

phpBB [video]