Curves workbench

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Chris_G
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Re: Curves workbench

Post by Chris_G »

UR_ wrote: Tue Aug 07, 2018 3:17 pm I've no clue what's going on :(
At the beginning of your file, the Base Helix is made of 2 edges.
This leads to a Section_pitch_curve that cannot be joined into a single curve.
I used JoinCurve on the base helix, and so I was able to join Section_pitch_curve into 1 single curve.
Also, if you attach your thread profile sketch to the upper end of the curve, you can use a standard attachment mode.
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UR_
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Re: Curves workbench

Post by UR_ »

Chris_G wrote: Tue Aug 07, 2018 4:03 pm Also, if you attach your thread profile sketch to the upper end of the curve, you can use a standard attachment mode.
I think that's only why "Revolve screw tip" has a nearly vertical tangent at the upper edge.

Changing "Sketch screw tip" will reveal this:

2018-08-07 19_03_26-FreeCAD 0.18.png
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But that's another question :)
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Chris_G
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Re: Curves workbench

Post by Chris_G »

UR_ wrote: Tue Aug 07, 2018 5:10 pm I think that's only why "Revolve screw tip" has a nearly vertical tangent at the upper edge.

Changing "Sketch screw tip" will reveal this:
OK, I see what you mean : you're right.
One possible solution is to duplicate CurveOnSurface and to switch it to output the Binormal face.
This way, you have the 3 perfect vertexes to attach the sketch as OXY
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bitacovir
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Re: Curves workbench

Post by bitacovir »

Hi. it is my first time testing CurvesWB, but tools like BSplineCurve does not work at all and the 3D view is just get frozen.

OS: Windows 10
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.14235 (Git)
Build type: Release
Branch: master
Hash: 7ad0c7f7f209c165370da2988ce51af70230c3bc
Python version: 2.7.14
Qt version: 4.8.7
Coin version: 4.0.0a
OCC version: 7.2.0
Locale: English/Australia (en_AU)
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hammax
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Re: Curves workbench

Post by hammax »

… Chris, sorry for hitting on the same wedge.
I tried to perform my ships propeller example with pure CurvesWB - and it works.
I had to split the profiles into a suction and a pressure half.
Full parametric, I also can control the blades' pitch by placement.
But... I am forced to use Draft-BSplines for leading and trailing edge - and they are NOT parametric.
The 3D-snapping potential (end point) is the desired but unfortunately not permanent feature.
If your feature for 3D-BSplines would work, maybe "some people" would be happy.
And a workflow description could be written or demonstrated (Normand's remark elsewhere).

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Pauvres_honteux
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Re: Curves workbench

Post by Pauvres_honteux »

hammax wrote: Fri Aug 10, 2018 9:10 am …"some people" would be happy.
+1 (and count me in!)
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Re: Curves workbench

Post by freecad-heini-1 »

Pauvres_honteux wrote: Fri Aug 10, 2018 10:09 am
hammax wrote: Fri Aug 10, 2018 9:10 am …"some people" would be happy.
+1 (and count me in!)
+1, me too ... hehe
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hammax
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Re: Curves workbench

Post by hammax »

… here is a complete Chris_G_ian CurvesWB example of parametric 3D-modeling of a blade halfprofile.
- starting with 2 pairs of parametric projection curves for LE and TE as 3D-BSplines
( a little bit scratching with the left hand on the right ear - not so easy)
- from this pair of 3D-curves a Ruled_Surface is derived,
- on the ruled surface there can be created some Profile_Planes by clicking at the wanted positions.
(look for the parameters position/height (0 .. 0,54 ..1,0) and direction x,y,z and adjust them - also right ear scratching,
Edit: after saving and reloading file, the planes get invisible (!) Visibility property doesn't work correct.
They can be activated again by editing e.g. x-value in properties.)
- on the profile planes the sketcher profiles can be generated - external and therefore parametric links to LE and TE are constrained,
- now with ruled surface and the 4 profile sketches the Sweep_2_rails is done,
- Sweep_2_rails at last can be converted to the Approximation_curve.
In the picture from bottom to top.
Prop_CurvesWB_2.PNG
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Last edited by hammax on Sun Aug 12, 2018 11:03 am, edited 3 times in total.
UR_
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Re: Curves workbench

Post by UR_ »

I have a little feature request:

Would something like this be hard to implement :?:

FreeCAD 0.18-000030.png
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If one will have lots of Sketches linked to lots of Profiles, they are really hard to maintain, especially if there are only small differences between the involved shapes.
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Re: Curves workbench

Post by freecad-heini-1 »

Hi Chris_G,
I have also a feature request, it concerns the possibility to snap to imported point cloud and create a bspline out of the points.

Please have a look at this thread:
https://forum.freecadweb.org/viewtopic. ... 12#p250612

That was hard work.
thschrader created a dwire face out of three points and used it as working plane.
No way to unhide points they are not on the same hight.

I wish to have a 3D spline to select and snap points in 3d view and create a bspline out of the points.

Best regards
Wilfried
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