SubD Ship Hull Modeling

Thank you for the good work so far on SubD modeling and features.
For the marine industry, there are a few vessel hull types that ask for SubD modeling and I did a test. It all looks very promising.
The attached hull is something that can be used for testing SubD: 11 Discourse SubD-ShipHull.3dm (4.9 MB)

Furthermore there’s a little Grasshopper script to make a lines plan and being able to do curvature graph analysis: (24.3 KB)

What I found out after generating a Nurbs object out of SubD, is that every panel is converted to a Nurbs patch. What I liked about T-Splines was that it was possible to convert areas to a single Nurbs piece as long as the panels had four sides. In the case of this hull that could be a big part of the hull shape. Is that something feasible?

What I miss right now for fairing purposes is:

  • Curvature graph

  • Surface Curvature Analysis


There is work going on in this area (called packing layout) that should be in the wip in the next few weeks or so-

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Thanks for the notes and testing! There’s an open request for curvature analysis SubD support filed as , I added your vote.


What area do you refer to Kyle? Do you mean Curvature graph and Surface Curvature Analysis?

Hoi Gerard -

It’s the generation of bigger NURBS patches that Kyle refers to.

Ah, that’s great. Thank you for explaining Wim.

@Gerard - This weeks WIP has a new packing feature in the ToNurbs command:

It is a first run at this. We still have more to do to it, but give it a try.


Thank you for your reply Scott,
The result seems perfect at first sight.
As we model in the marine industry often only one side of the hull and mirror that at center line (CL), I trimmed the bow part at CL and shrank the control points. That worked well too.

By the way, the renders look very nice. Can you share the file with me please?

Here is the file. 11 Discourse SubD-ShipHull to nurbs collapse.3dm (7.9 MB)

For rendering is is nothing special other then the new Rhino 7 Rendered mode with edges showing and:

  1. Default plastic materials
  2. Groundplane turned on with shadows.

Of course I had to turn the hulls upside down to get them to lay on the ground that way.


you may add my vote too.
Do you know if Orca 3d will support SubD?

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Many developers are starting to test for comparability as the SubD tools have now stabilized a bit.

You will have to ask them. @brucehays - would be the best person for the most up to date information.

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ok, thanks

Our testing has shown that Orca3D works smoothly in Rhino 7, and SubD surfaces are compatible with calculations such as Sections, Hydrostatics & Stability, Speed & Power, and Weight & Cost. Real-time sections currently do not work with SubD models; that is, the sections don’t update as a control point is moved, but they do update when the control point is put down.

Orca3D Version 2.0.19 is compatible with both Rhino 6 and Rhino 7, and Version 2.0.19 is a free update to those with a Version 2 license.

If you currently use Rhino 4 or 5 with Orca3D Version 1, you will need to upgrade to Orca3D Version 2 to be compatible with Rhino 6 or 7.


Subd is Ammmmazing for real time optimization in functional models… back in the tsplines days, there were several folks feeding tsplines models to an AI and letting it optimize …I never saw a commercial product come from it, but the technology/ possibilities was pretty incredible.

You mean like, making the calculations in real time and using a neural network to find the optimal shape for a hull ?

a lot like that! :slight_smile: