Vertical Fins

Hi im trying to generate vertical fins on a curved surface, im having problems to connect the the points to a curve which i generated on the surface.

Could you guys have a look at it and give me some tips.

best

mac

Attachments:

fins.gh, 10 KB
surface.3dm, 143 KB

Replies to This Discussion

Permalink Reply by Joseph Oster on October 30, 2017 at 9:19am

So you are a professional - can I send you a bill? ;)

Using 'Extr (Extrude)' for thickness was probably a mistake (mine); 'Loft' didn't work and I took an expedient solution. 'Offset surface' is really better when the surface might be twisted and not planar. Fixed in this version.

I'm not so sure about the way I replaced the vertical isocurves either... Could have used 'CrvSrf (Curve on Surface)' instead... Not sure of the effects when the number of intervals is reduced?

Attachments:

fins_2017Oct30a.gh, 42 KB

Permalink Reply by Joseph Oster on October 30, 2017 at 10:15am

I'm not so sure about the way I replaced the vertical isocurves either... Could have used 'CrvSrf (Curve on Surface)' instead... Not sure of the effects when the number of intervals is reduced?

Just out of curiosity, I added 'CrvSrf' as an alternative to 'IntCrv' for the vertical lines - and a yellow group to measure the maximum difference between the two curves. Only 0.0285 'Max Diff' in this model, though I suspect it might be more if the surface was more curved?

Attachments:

fins_2017Oct30b.gh, 48 KB

Permalink Reply by Joseph Oster on October 30, 2017 at 12:38pm

Curiosity again... I decided to test theory by giving your tower some twist (off-center rotation) and found a couple of things.

'CrvSrf (Curve on Surface)' doesn't work well. Tested with eight and with 47 interval points (section planes); lines wrapped around the tower and went otherwise goofy.
'IntCrv' looks much better but on closer examination, several lines fail to 'Pull' to the twisted surface. Looking at that... 'Shatter' is failing, don't know why yet.
'Loft' with the offset surface failed on most of the fins, so I went the more elaborate route, lofting the edge curves.

Attachments:

fins_2017Oct30c.gh, 55 KB

Permalink Reply by Joseph Oster on October 30, 2017 at 1:37pm

'Shatter' is failing, don't know why yet.

Found and fixed the problem by adding this function to filter 't' values less than "0.00001" - "if(x<0.00001,0,x)":

Attachments:

fins_2017Oct30d.gh, 55 KB

Permalink Reply by Joseph Oster on October 30, 2017 at 4:03pm

30 degree rotation:

Attachments:

fins_2017Oct30d.gh, 55 KB

Permalink Reply by Maciej on October 30, 2017 at 11:19pm

haha actually im not a professional, im working but also still a student.

Permalink Reply by Maciej on October 29, 2017 at 11:44pm

Joseph thanks a lot, you helped me a lot and learned quite a bit thanks!!

Permalink Reply by Maciej on October 31, 2017 at 4:54am

Joseph hi

actually i think i found a problem every time i do divide the curve with around 50 the segments of the fins are wrong there is some mistake but i cant find out what it cause.

( never mind i think i did a mistake)

Permalink Reply by Joseph Oster on October 31, 2017 at 5:45am

Be sure to use the latest version ( fins_2017Oct30d.gh ). You can skip the rotated tower by wiring the 'Orig Srf' directly to the 'Srf' input for the fins.

Permalink Reply by Joseph Oster on October 31, 2017 at 6:38am

Oops, sorry, that doesn't work. The cross section curves need to be wired too.

Here is a stripped down version of the latest code, minus the twisted tower:

Attachments:

fins_2017Oct31a.gh, 41 KB

Permalink Reply by Joseph Oster on October 31, 2017 at 7:44am

I encapsulated the code that thickens the fins into a general purpose cluster. It uses 'Offset' surface, 'Loft' edges and brep 'Join' to return "Closed Breps". It could easily be modified to offset in both directions, returning a brep centered on the original surface instead of being on one side or the other (w/ negative thickness).