Curves workbench

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hammax
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Re: Curves workbench

Post by hammax »

...Chris_B's curveWB is a real bringer.
I tried sail-design again, this time with learningcurve. Bendt mast, sail-transition to straight boom, leeward swept trailing edge, all in.
You can use wires AND sketches for profiles and rails...
Sail_3.PNG
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chrisb
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Re: Curves workbench

Post by chrisb »

hammax wrote: Wed Jul 05, 2017 9:51 am ...Chris_B's curveWB is a real bringer.
With the second part of that statement you sure are right, but the first part is awfully wrong. I feel honoured, but this Workbench is from Chris_G.
ChrisB
A Sketcher Lecture with in-depth information is available in English, auf Deutsch, en français, en español.
freecad-heini-1
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Re: Curves workbench

Post by freecad-heini-1 »

hammax wrote: Wed Jul 05, 2017 9:51 am ...Chris_G's curveWB is a real bringer.
100% agreement! 8-)

I wonder how to change the number of bspline poles. It's so easy because it's possible to exchainge a sketch completely new.
Look at sketch003. I edit the sketch, draw a new bspline with more poles, deleted the old one - the result - a full parametric new surface. Whow - that is really a great workbench! :lol:

What about the guitar maker here?

The tiede bottle is reachable:
https://www.youtube.com/watch?v=FnuxoUltj_I

The missing piece, from my point of view, the possibility to define tangent constraint to neighbor surfaces.

Best regards
Wilfried
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Chris_G
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Re: Curves workbench

Post by Chris_G »

Hi,
Thanks for the kind words.
I don't have much time these last days.
But here is the latest tool : a blendSurface.
First, you need to create a "Curve on Surface" object.
The tool needs a face and an edge selected.
cos.jpg
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The green lines show the normals along the edge.
The blue lines show the Binormals along the edge.
They can be reversed in the properties, if desired..
By selecting 2 "Curve on Surface" objects, you can create a blendSurface :
blendsurf.jpg
blendsurf.jpg (70.27 KiB) Viewed 6898 times
That surface can be approximated by a face, the same way as for Sweep2Rails.
This surface is "approximately" tangent to the 2 generating faces.
I say "approximately" because (same as SweepOn2Rails) the process involves some sampling / approximating, so the tolerance depends on the number of samples and approximation tolerance.

Funny, it is even easy to "reconstruct" a kind of torus from the initial face of the screenshots :
torus.jpg
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hammax
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Re: Curves workbench

Post by hammax »

...you get even more funny results, if you change the orientations of the normals/binormals.
Only problem is, if the body is moved away by replacement, the blend always remains at the original Position.
Blend_0_0.PNG
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easyw-fc
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Re: Curves workbench

Post by easyw-fc »

Chris_G wrote: Sat May 27, 2017 3:27 pm Important foreword :
- I am a very bad coder, and this workbench is probably very badly coded.
- So please don't use it for any serious work
What about the guitar maker here?
Hi Chris_G
Chapeau! Great WB! :D
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Chris_G
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Re: Curves workbench

Post by Chris_G »

hammax wrote: Fri Jul 07, 2017 1:06 pm Only problem is, if the body is moved away by replacement, the blend always remains at the original Position.
I noticed this too. I'll have a look at that.
easyw-fc wrote: Fri Jul 07, 2017 1:38 pm Hi Chris_G
Chapeau! Great WB! :D
Thanks. So, you speak French ? :lol:
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hammax
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Re: Curves workbench

Post by hammax »

...I also tried to do some airfol-to-hull-blemd (Yak-example).
But at the trailingedge there is a crossover in the wireframegrid. Maybe thats the cause FC got into endless calculation.
Airfoilblend.PNG
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Chris_G
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Re: Curves workbench

Post by Chris_G »

This is why I keep the surface creation as a separate final step.
So, when you see that kind of bad result, you get a chance to not put FC into an endless loop.
And it looks like the blendSurface will need more work before it can work on that kind of test case.
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microelly2
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Re: Curves workbench

Post by microelly2 »

It's a common problem to get good borders for BSpline surfaces.
I add two extra rows of poles , calculate the surface and then delete the outer segments with the artefacts.
Doing the same for the other surface brings the edges together.



the problem is to get a good top
bp_522.png
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here the surface is cutted and a new top surface is created which fits the middle shoe
bp_524.png
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