Curves workbench

Post here for help on using FreeCAD's graphical user interface (GUI).
Forum rules
and Helpful information
IMPORTANT: Please click here and read this first, before asking for help

Also, be nice to others! Read the FreeCAD code of conduct!
User avatar
hammax
Veteran
Posts: 1985
Joined: Thu Jan 19, 2017 5:03 pm
Location: Ammersee DE

Re: Curves workbench

Post by hammax »

...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
Airfoilblend_2.PNG (104.72 KiB) Viewed 7682 times
Attachments
Airfoilblend.FCStd
(66.23 KiB) Downloaded 178 times
User avatar
Chris_G
Veteran
Posts: 2580
Joined: Tue Dec 31, 2013 4:10 pm
Location: France
Contact:

Re: Curves workbench

Post by Chris_G »

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
Posts: 875
Joined: Tue Apr 28, 2015 11:23 pm

Re: Curves workbench

Post by emills2 »

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
Silk_model_75_01.png (306.84 KiB) Viewed 7601 times
surfaces cannot be made to match (in a simple way)
Silk_model_75_02.png
Silk_model_75_02.png (335.57 KiB) Viewed 7601 times
emills2
Posts: 875
Joined: Tue Apr 28, 2015 11:23 pm

Re: Curves workbench

Post by emills2 »

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
Silk_model_75_03.png (504.17 KiB) Viewed 7601 times
emills2
Posts: 875
Joined: Tue Apr 28, 2015 11:23 pm

Re: Curves workbench

Post by emills2 »

muhahahahahaha! 100 combs per surface! full curvature mapping! so...much...power :o
Silk_model_75_04.png
Silk_model_75_04.png (735.16 KiB) Viewed 7599 times
emills2
Posts: 875
Joined: Tue Apr 28, 2015 11:23 pm

Re: Curves workbench

Post by emills2 »

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
Silk_model_75_07-resize.png (608.93 KiB) Viewed 7592 times
User avatar
microelly2
Veteran
Posts: 4688
Joined: Tue Nov 12, 2013 4:06 pm
Contact:

Re: Curves workbench

Post by microelly2 »

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. ;)
User avatar
regis
Posts: 725
Joined: Sun Jul 12, 2015 8:17 am
Contact:

Re: Curves workbench

Post by regis »

phpBB [video]
User avatar
Chris_G
Veteran
Posts: 2580
Joined: Tue Dec 31, 2013 4:10 pm
Location: France
Contact:

Re: Curves workbench

Post by Chris_G »

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
Posts: 875
Joined: Tue Apr 28, 2015 11:23 pm

Re: Curves workbench

Post by emills2 »

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.
Post Reply