Curves workbench

Have some feature requests, feedback, cool stuff to share, or want to know where FreeCAD is going? This is the place.
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hammax
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Re: Curves workbench

Postby hammax » Sat Jul 08, 2017 2:23 pm

...the airfoil2hull-blend works, if you only draw halfprofiles.
If the wireframe is twistet, one of the profiles (bsplines) must be drawn from the trailingedge first.
I was confronted with some "sensibilities" in drawing clockwise or counterclockwise ....

Edit: meanwhile I have found in "Blend_Surface" -Data-tab a line "Untwist"
Is that the riddles clue?
Airfoilblend_2.PNG
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Chris_G
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Re: Curves workbench

Postby Chris_G » Sat Jul 08, 2017 4:38 pm

Indeed, it works better on half profiles.
hammax wrote:
Sat Jul 08, 2017 2:23 pm
If the wireframe is twistet, one of the profiles (bsplines) must be drawn from the trailingedge first.
I was confronted with some "sensibilities" in drawing clockwise or counterclockwise ....
IMHO, in OpenCascade, edge orientation is quite a pain to deal with ...
So I switched to workarounds.
The use of a Ruled_surface as input for the sweep2Rails tool is a way to be sure to get the rails correctly oriented.
hammax wrote:
Sat Jul 08, 2017 2:23 pm
Edit: meanwhile I have found in "Blend_Surface" -Data-tab a line "Untwist"
Is that the riddles clue?
This "untwist" property is another way to deal with the problem ...
emills2
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Re: Curves workbench

Postby emills2 » Thu Jul 27, 2017 6:02 am

Hi Chris,
i just found out by accident that found out by accident that the Comb tool works on Surfaces, not just curves. this is really awesome! i have a little problem though. With curve, i can match the scales and the combs will 'click' together when the curve is G2. with the surfaces, even setting the scales equal doesn't line them up patch to patch. Would you consider making the scale absolute instead of relative to object size? (just a guess)

the fact that the surfaces return the curvature in the surface normal plane makes those combs much more informative for surface diagnostic, and the U/V multi iso is just...wow! can we get U+V as an option too? :lol:

curves matching when the scale matches
Silk_model_75_01.png
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surfaces cannot be made to match (in a simple way)
Silk_model_75_02.png
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emills2
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Re: Curves workbench

Postby emills2 » Thu Jul 27, 2017 6:11 am

And thanks again for the Zebra! that thing is sick. and dangerously hypnotic.

Sure enough, Zebra finds the flaws. Getting close though.
Silk_model_75_03.png
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emills2
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Re: Curves workbench

Postby emills2 » Thu Jul 27, 2017 6:24 am

muhahahahahaha! 100 combs per surface! full curvature mapping! so...much...power :o
Silk_model_75_04.png
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emills2
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Re: Curves workbench

Postby emills2 » Thu Jul 27, 2017 7:08 am

last post i swear...but i really love these tools.

double combs for UV overlay and manual scale mapping to connect the combs patch to patch.
Silk_model_75_07-resize.png
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microelly2
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Re: Curves workbench

Postby microelly2 » Thu Jul 27, 2017 1:39 pm

emills2 wrote:
Thu Jul 27, 2017 7:08 am
last post i swear...but i really love these tools.

double combs for UV overlay and manual scale mapping to connect the combs patch to patch.
nice to see these results, I'm waiting for a testcase and the scripts you used for this. ;)
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regis
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Re: Curves workbench

Postby regis » Thu Jul 27, 2017 1:48 pm

phpBB [video]
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Chris_G
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Re: Curves workbench

Postby Chris_G » Sun Jul 30, 2017 10:33 am

emills2 wrote:
Thu Jul 27, 2017 6:02 am
Hi Chris,
i just found out by accident that found out by accident that the Comb tool works on Surfaces, not just curves. this is really awesome! i have a little problem though. With curve, i can match the scales and the combs will 'click' together when the curve is G2. with the surfaces, even setting the scales equal doesn't line them up patch to patch. Would you consider making the scale absolute instead of relative to object size? (just a guess)

the fact that the surfaces return the curvature in the surface normal plane makes those combs much more informative for surface diagnostic, and the U/V multi iso is just...wow! can we get U+V as an option too? :lol:
Hi Edward,
The comb plot tool DOESN'T WORK on surfaces for now.
I tried to implement this, but didn't finished the job.
The curvature values that are computed for surfaces are probably wrong, they are the curvatures of the iso-curves, not the surface curvatures.
Maybe I'll try to rework this, but I am not sure to understand all these curvature things ( principal, mean, gaussian, geodesic, etc ... I get confused ).
emills2
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Re: Curves workbench

Postby emills2 » Sun Jul 30, 2017 11:28 am

damn! are you sure? they look like curvatures of the iso along the surface normal. a curve comb would dance up and down wildly like my first picture above.

i guess i have to take your word for it....but i'm still going to use them anyway! :lol: they look meaningful to me and they react the way i expected them to. except the scale part.