NURBS surfaces should be called NURBS membranes


The noun surface is confusing because it has two meanings: very thin membrane, and exterior boundary of a thing. I believe that NURBS surfaces should be called NURBS membranes, or NURBS skins, or NURBS foils.




Is clarity boring?


I’m pretty sure they’ve been called “surfaces” by the industry since long before Rhino existed, so whether it makes sense or not they’re “surfaces.”

Also, depending on what you’re doing either or both of your meanings are entirely appropriate.

Yes I’m procrastinating!


No, but there are real issues that need to be resolved with this new release, so wanting to change long established terminology just because it pops into your head seems like the musings of someone who is bored.


Yeah, but when you see one of these in your Rhino window

And you ask people whether it is a surface or a boundary, what do you think they are going to answer?

Sometimes you need to use common terminology because it is what most people understand.

And the boundary in this case (if you’re talking BREP terminology) is actually the edge of the surface, not the surface itself.

Boundary representation of models are composed of two parts: topology and geometry (surfaces, curves and points). The main topological items are: faces, edges and vertices. A face is a bounded portion of a surface; an edge is a bounded piece of a curve and a vertex lies at a point. Other elements are the shell (a set of connected faces), the loop (a circuit of edges bounding a face) and loop-edge links (also known as winged edge links or half-edges) which are used to create the edge circuits. The edges are like the edges of a table, bounding a surface portion.


Maybe we shouldn’t call cars automobiles, because they don’t drive themselves yet. That’s coming in 2020. So let’s rename them “manualmobiles” until the fully autonomous cars hit the market. :laughing:

Oh, and better stop driving on the parkways and parking in the driveways while we’re striving for clarity.


LOL!! :rofl:

(Nathan 'jesterKing' Letwory) #10

And perhaps not shutdown machines from the start menu.


i believe that was not the question, the OP was suggesting a REdefinition and not how we define it currently. also when i logically think, the word boundary would suit in exact this specific case far better, since a surface would imply etymologically correct that something would be attached to it which in this case with this abstract, mathematical, in the real world non existing entity would not apply.

not only sometimes. traditionally we mess words and their meanings up, they get scattered into different languages getting different meanings and sometimes even meaning the exact opposite, leading to different groups of people talking about different kinds of things when they meet. that is one reason to keep terminologies dynamic to recalibrate and realign each other.


That’s clearly a pristinely ironed Kobe period handkerchief with minmalist Yukarashi graphics applied. A rare masterpiece and collectible item.


The question is, rather, in the driveway or on the driveway…

If one throws the OP’s suggestion under the bus, will the bus have enough ground clearance to roll over?


Ergo, since you can’t actually do anything with the etymologically correct abstract, mathematical, in the real world non existing “surfaces” that you imagine you see on your computer screen, Rhino is actually useless.

Good, yes, myself guessed myself have yours meaning, prevent, that’s only way to abstract of I tiny little brain, then myself would do continuity using words this myself and most other people around my with able to understand…

Kinky sweep
(Nathan 'jesterKing' Letwory) #16

Yup, rendering/raytracing is all fake. Some fake just looks better than other fake. And I love working with fake.


P.S. I am a linguist


3D is a fad. Use your unlimited degree of freedom milling and chiselling machine. All above G0 is a con.


valid in real life qantum mechanically and of course also virtually binary either on, or off, or both.

(Gustavo Fontana) #20



Call it whatever you want, while working with curves, closed curves, surfaces and solids: the name may not necessarily reflect its true description. i.e. in the 1960’s they named a band the Beatles, they didn’t look like bugs, smell or act like bugs, but they sang great music. You know them for what they do or did.


(David Rutten) #22

To be completely pedantic about it, I think it should be called NURBS Patch. A (mathematical) surface can do a lot of things that nurbs surfaces can’t (complex topology, disjoint regions), a “boundary” must always delineate a volume or at least separate two regions of space, a “skin” implies that it is wrapped around an interior (again connotations of volume and enclosed regions), “foil” has no mathematical meaning as far as I know, but it does conjure images from fluid dynamics.

Coordinate patches are mathematically speaking most similar to the UV domain of a nurbs surface. They’re also called “charts” within topology because they make up an “atlas” which covers an entire mathematical manifold. The only problem is that patches are usually considered to be open intervals whereas nurbs surfaces have a clear, valid boundary.