Undevelop a surface?

I want to make a 3d model of a stitch and glue boat hull. I have the plans which show the shapes of the hull pieces that will be cut from flat plywood, and then formed into a hull shape by stitching the edges. I want to build a CAD model first, and I am wondering if there is a way to stitch these flat shapes together in rhino, essentially it would be un-developing the surface. Any thoughts?

If you’re looking for a way to take a 2D drawing and create a 3D version automatically, there isn’t a way to do this without manually drawing the curves needed for the surfaces. You might be able to use Crv2View though to make a 3D version of the two orthographic views.

I don't think I expect to find an automatic way to do this, just a way to do this in cad with just the flat shape data, no other profiles, sections or plans provided.

In my mind I imagine trying to rebuild a banana shape if you are just given the shapes of the 5 peels, (each being a side of a five sided banana). I will take a look at the crv2view command.

This is possible but super tedious. You need to segment the flat cut shapes into flat segmented panels. Take two that you know meetup spine to spine, then manually manipulate the orientation of each separate segment until all are meeting properly. There could be a cool Grasshopper or script way of doing this out there somewhere. For rough approximation the bend tool works well for this, with the rigid=no option. Then manually tweak each panel with the rotate3d command. This of course applies only to simple ruled surfs that roll in one direction.
screenshot showing rough idea. Of course you’d be starting with something flat like the green shapes. Purple was used to generate.

Not the suggestion you were hoping for and probably obvious, but another approach to this - from the photo, you have good access to the hull so you could fabricate a moveable, simple frame with a transverse grid marked at 100 crs or so and measure offsets down to the hull surface at these spacings with a plumb-bob (what’s one of these called in the US), and measure to key intersects from the frame at say 500 crs, tighter at the bow.

Then feed the offsets into Rhino, create the sections and geometry from the offsets then loft the surfaces - unroll the result and use your templates for comparison and fine tuning. Would be a fun exercise as well as being accurate …

Hey, that’s one of my designs :wink:
PH16 I think, maybe the PH18 from bateau.com

It is very simple to create that model but forget about the panels.
Why don’t you use the lines plan and do 3D from 2D? I don’t show lines in a table of offsets but all the points are there.

BTW, that’s an old model that I created 25 years ago in Nautilus. The new model will not be 100% accurate so if you try to mix and match parts from the 2 models, It may not work perfectly.

Hi Jacques,

Actually I do not know what boat is in that picture, I just found it online via Google image search and used it to explain what I was trying to do. You are probably right that it is one of yours!

I purchased C17 and an LB22 plans from you and I am trying to build them in CAD. I am trying to figure out which i want to build. I starting to think maybe a P21 would be better for me.

So I posted this note to see if there was an easy way to construct the hull in CAD just from the developed panels but it seems not. I went ahead and used the lines from the C17 plan to reconstruct in 3D, with some good results. I am thinking of making the cabin a foot longer by lengthening it so I can fit in the bunks. This would require moving the helm back but I think the boat is too small for this.I built the C17 model in SolidWorks, but I am going to try the LB22 in Rhino.

I am going to try to go to the meet in Texas, maybe I will see you there.