How to flaten bow of the boat to get flat pattern?

Hello, I am trying to make a flat pattern of a bow which has to be one piece of aluminum, it also has bend marks for bending and will finally be deformed while welding to achieve the final shape. unrollsurf, squish and smash are not giving satisfactory results. Is there a technique or addon I should be using to get desirable results?

Thank you for your time.bow.3dm (225.1 KB)

Rhino can´t unroll this kind of triangle surfaces correctly. Better to design all surfaces with 4 edges, or at least as trimmed surfaces with proper rectangle cv layout. If you can´t modify I the design, I can unroll for you with some other tools.

Hello - I guess the shape cannot be unrolled to a single sheet without the deformations you mention - If you mesh the object using the Mesh command Squish will make you a single ‘triangle’ but I would not have much faith in that reversing the specific deformations that will be done…


UnrollSrf in Rhino works on “trianglular” surfaces with three sides provided the shapes are developable with isolines aligned with the surface ruling lines, which is the same requirement to use UnrollSrf on surfaces with four sides.

The shape in the original post cannot be made from one sheet as desired without large amounts of stretching and/or shrinking. That’s due to physics, not software limitations.

@JoergH that would be helpful, can you please suggest tools to do the same?

I am sorry, but I was just looking at unrolling the single surfaces. In Rhino the bottom plate does not unroll properly. This one I can unroll in some other solutions. But the next plate does not unroll in my software, but in Rhino it unrolls within tolerance. I don´t think that it is a good idea to build the surfaces with so many cp stacked. David is absolutely right, hull surfaces that shall be unrollable should be designed as ruled surfaces. And Pascal is of course right: it is not possible to make this shape from a single sheet of metal plate without a lot of stretching by using something like a deep draw process, just bending is not possible. What kind of boat do you want to build? Length ? Aluminium thickness? What process?

If the material is thick enough for welding - why don´t you just weld this piece?

ExactFlat plugin is better than Smash and Squish commands:

Only if you can afford ExactFlat.

UnrollSrf should be satisfactory for a properly designed developable surface.

Thank you for your precious time. These are shallow water boats of 18 feet (approx 5.5 meters) length, the aluminum is 3.33 mm in thickness, The hulls are bent using a break press.

I tried exact flats but the results weren’t satisfactory, Maybe I should ask a salesmen for a demo.