SubD from Curves?

Hi, Im new to SubD, and trying to create these root-like surfaces in SubD

The structure of the root branches makes it intuitive to create the shapes using CrvThroughPT combined with History, which makes it easy and intuitive to define the “spine” curves" and the “edge” curves, simply by nudging the points.

But how do I then create a SubD surface from those curves?

And would it be possible to update of SubD Surface in History mode, by nudging the points?

I tried SubDLoft, but the Curve system is probably too complicated for this command to work in this case here ?

I then tried splitting curves, and rebuild curve segments to SubD friendly, but still , the SubD Loft command is making weird output ?? (See attached file “SubD Loft.3dm” )

Another idea was using the “spine” curves, to make a SubD Multipipe, and then delete the inner faces of the Multipipe. Promising prospect, but it ends up being a lot of nudging control points, and the SubD surface is not anywhere near the intended surface, defined from the CrvThroughPt - curves

I have attached file “SubD from Curves?.3dm” for exploring ideas and demonstrations.
Any suggestions or tips to a nice workflow here would be greatly appreciated !

Thanks !

SubD Loft.3dm (2.5 MB)

SubD from Curves?.3dm (2.7 MB)

Is the end desired result something that is ‘flat’ in nature, or pipelike? The curves you suggest suggest the former, but talking of being rootlike naturally suggests the latter.

I’m wondering if it would be better, if trying to get something that Is a flattish, free form surface, to use the 3d face tool and building up the object. Where you have the se points where you would like to be able to ‘nudge’, just ensure you a subD vertex going through it. Toggle from sharp to smooth mode, and sculpt the object as desired.

“Flat” in nature.

the “root” like expression, is to convey the logic of the structure, meaning there is a core line in each (flat) branch.

  • maybe imagining a sea-weed would be a better expression :slight_smile:

Thanks for your input, but I dont really understand the technique ? What commands should I use to work with “3D face tool” ? And what is “SE points” ?

This is very close to what I imagine ending up with…
(only this is not controlled by edge curves, it is made up from the “half” multipipe B
that I then have spent some time nudging the control points…)

How do I divide the faces just along the edge?

MultiPipe B.3dm (2.4 MB)

Very similar to that and as it is mesh it could become subd easily

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Yes very similar (and beautiful forms in Grasshopper)
But I need the artistic freedom to control every curve in the shape manually.
(and also, I am not that strong in Grasshopper either…)

I build these ideas in real life, with a material called FerroCement (steel rebar, chickenwire and concrete) The building process is actually very similar to the principal of surfaces from splines in Rhino.

subd sweep1 and stitch should get you there.

the spines are all split at the intersections, then the sweep goes from bottom to top, you then stitch the edges together and you can then very precisely control the shapes. Just make sure to have your profile curves be rebuilt subd friendly at the same segment count

SubD surfaces have zero curvature normal to naked edges and creases. That is how the SubD surfaces work in Rhino. There are “SubD friendly” curves which have zero curvature at the ends.

Some commands have an option to create SubD friendly curves but CurveThroughPt does not. SubD surfaces cannot follow curves which end with non-zero curvature, such as the curves you are using. MakeSubDFriendly will convert curves to be SubD friendly though the shape will change.

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I would be tempted to say you’re pretty much there with that solution.

Do you need to iterate a ton of these with something such as grasshopper? Or create loads of variations from slightly different starting curves? If not and you just want to match one shape, use EditPtOn and manipulate the vertex points themselves to fit your design intent.