Full Version: boat hull

how can I model this so that both the sides and the middle profile align with the rest of the hull? I used sweep to achive this, first selected the middle line, then the arc as a profile. moving the points of the middle line, gets me either alignment of the sides or of the center profile, not both. the main hull is a loft with only 3 curves.

Image Attachments:
Screenshot 2026-09-28 at 13.16.19.jpg 

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Normally you have a native cool tool Transform : Orient / Line-line and select few regulates following that you want! :)

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I am sorry, but that is not the problem, the curves do not follow a smooth path, there is a dent in the skin, either at the bottom, or left and right, depending on the vertical curve.

Image Attachments:
Screenshot 2026-09-28 at 19.36.50.jpg 

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Maybe you could draw those top curves in to use as construction geometry instead of looking for sweep to adhere to the unknown

I would use blend to create the top curves from the surface to the point, then have 4 tangent curves to work from

Cant test without a file…

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You want or don't want this dent ? :)

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ok, I will rephrase my question: how can I finish this lofted open shape, so that the end is smooth and round and has no visible division line, so that it looks like one continuous smooth object?

thanks
wim

Image Attachments:
Screenshot 2026-09-28 at 20.55.36.jpg 

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Maybe Network ?

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HI wim,

re:
> how can I finish this lofted open shape, so that the end is smooth and round and has no
> visible division line, so that it looks like one continuous smooth object?

It's hard to give good advice just looking at a screenshot, can you please post the .3dm model file with the objects you show there?

Probably the first thing I would try would be to use Rail Revolve to make the rounded end and then have some empty space between that rounded tip and the main part and then use Construct > Blend to put in a smooth blend surface.

Or another possibility is to cut the end edge in half and then use Blend between the 2 halves.

Also using Loft with Loft style = "Loose" and ending in a point can be good, an example:
https://moi3d.com/forum/index.php?webtag=MOI&msg=6082.8

- Michael

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here is the .3dm file

w

Attachments:
loft-sweep.3dm

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mm with 7 decimals is maybe not the best for a boat ?

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Hi,

I think, Pilou have a good way with Networks.

But if you don't want have a bad continuity with the main piece, you must use Blend function to generate the curves used by network.
I attach my file with colors to understand what I used,
blend between the 2 red curves
blend between the 2 orange curves
blend between the 2 cyan curves

Then, use network with the curves you obtain by blend function (in my file, I assign those curves as Blue).

Don't know if this is the best way but it seems to be ok.

Attachments:
loft-sweep_ph.3dm

Image Attachments:
Capture d'écran 2026-09-29 004345.png 

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I used the Sweep tool.
The green curves were used for the profiles and the red curves were used for the rails. The blue curve was used for the scaling rail.
If you show points on the curves, it's quite easy to alter the shape as required.

Martin.

Attachments:
loft-sweep-Martin.3dm

Image Attachments:
Screenshot 2026-09-29 005124.png 

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Hi wim, thanks for posting the file.

So for the blend method you can set up a cutting curve like this:


Use Trim or Boolean Difference to make an opening:


Select these 2 edges:


Run Construct > Blend to fill in the empty area with a smooth blend surface:




- Michael

Image Attachments:
wim_hull1.png  wim_hull2.png  wim_hull3.png  wim_hull4.png  wim_hull5.png 

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Hi wim, this construction method is using Loft style = "Loose" with end points to make a rounded tip directly in the lofted surface:







- Michael

Attachments:
loose_loft.3dm

Image Attachments:
hull_loose_loft1.png  hull_loose_loft2.png  hull_loose_loft3.png 

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Cool! :)
Like this you can keep the original forms even in Loose process!

Just make the extremities "free" (double the penultimate section for example)
You can of course transform them after!

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wow, thanks all, lots of approaches to pick from! will try them all and document them for my personal tutorial library! (if not I will have forgotten it next time, my neurons became a bit fuzzy lately ;-)

will try to show the result soon, a slowly rocking wooden sailboat automaton.

cheers
wim

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needs to be 3D printed as a test first, Pilou ;-) and yes, I forgot to reset the decimal display to 2 after some scaling tests for another project...

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