Cutting surface in strips / Projection in 2d plane


I would like to project the surface of a boat’s hull, in strips to 2d plane, so that i can produce the drawings for cutting the wood for construction purposes.

I have the surface, but i dont know how to create the strips and then project them.

Could you please advise if this is possible in Rhino and how ?

These are the strips which projection i am trying to produce:

Thank you very much.

Hello - use UnrollSrf for this.



Many thanks for your response. Unfortunately the unrollSrf did not work. A msg appeared that cannot unroll doubly curved surfaces. Tried the smash command instead but it seems that the edges dont have the same legth as the projection.

Regarding cutting the surface in strips , are there any suggestions ? I would like to select points on the surface to create the strips, or creare equally spaced strips along the surface.

Thank you very much.

You need to split the surface into individual plank faces before unrolling.

Is the surface smoothly curved or does it have the individual planks?

Can you upload the file with the surface? If so either drag it to where you type your post, or click on the vertical arrow icon above where you type your post.

How much experience do you have with Rhino?

Unfortunately i dont have much experience in Rhino and i have no idea how to split the surface into planks.

I havent finalised my surface yet and i tried to use the unrollsrf to a test surface and didnt work. I will upload this tomorrow morning.

Many thanks for your help. It is highly appreciated.

  1. You can start by drawing the profiles that will be the planks
  2. use interpolated curve between “InterpCrv” profiles
  3. Use the command Sweep 2 rails “Sweep2”
  4. then use the Extract surface command “ExtractSrf”
    and finally the UnrollSrfUV command

    example ↓
    boat.3dm (915.2 KB)

Good day to all. Many thanks for your interest.

I am uploading the surface which however is not the final surface. It is just a test.

I have created the hull surface by drawing the frames, the transom and the upper plane of the boat and used the NetworkSrf to create the surface. It is difficult to draw the planks from scratch and i was hoping i could get the planks from the created surface and then project them in a 2d plane. Is this possible?

Thank you all again for your help.

test.3dm (220.4 KB)


Curves representing plank edges can be created on the surface using CurveOnSurface or InterpCrvOnSrf.

After creating the curves for the plank edges, the surfaces of the individual planks can be created using Loft with each pair of plank edges.

UnrollSrf the planks.

The surface has many more control points than needed. It can be Rebuilt with 8 x 8 control points with only a small deviation from the current shape.

After creating the plank edge curves Rebuild each with 6 to 10 control points to reduce complexity.

have a look at this

test.3dm (772.5 KB)

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The disadvantage of that method is the user has no control of the shape of the planks. It completely depends on the parameterization of the surface. In Eftyhiadalma’s example each plank would end in a point at the upper corner of the bow.

Wow! Thank you all very much for your help.

The video was very helpful. I had already tried to make the hull surface with sweep2 without much success because i hadn’t thought of breaking the bottom edge surface in the front part in two.
I will try both suggestions, either to create the planks myself and then unroll or edit the surface as shown in the video.

I will let you know of the outcome.

Many thanks!

I don’t know if I understand, but Eftyhiadalma uploaded two different ship models.
I am basing in the first example, which is the image,
I don’t know if he had problems creating the surface with the characteristics of the first image.

Sunday night playing with Grasshopper. In this definition you can adjust the bow’s lenght for better shape for the strips (more straight). Got some problems with internalize, so it’s better with the joined 3dm file. You will need some plugins (pufferfish, parakeet)

test2.3dm (664.9 KB) unrolled strips for (18.1 KB)

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Yes, actually if you play with the length of the curve segment you can make the planks straighter.

Thank you all for your suggestions.

Unfortunately during the week I dont have spare time to work on my design project. :frowning:

I will get back at you during the weekend with the progress!

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