In areas like architecture where buildings and materials can and often are comprised of both 'rational' (triangles, quadrangles) and 'irrational' polygons (pentagons, hexagons, heptagons and other n-gons), using NURBS can be cumbersome and difficult when working with non-quadrangular geometry.

Despite that NURBS often lowers the amount of shapes necessary, in simple instances like an extruded pentagon... NURBS can add unnecessary geometry.



However-- in my limited knowledge on the topic-- there is no real benefit when it comes to finished product.

When outputting any 3D data to be used in the real world (fabrication) or semi-real-world (video games et cetera), most things are incapable of taking NURBS as is.

Everything is converted to a polygon mesh (which is essentially a triangulated surface). The advantage with working in NURBS or meshs is that the geometry is calculated through the polylines themselves.

In pure polygon modeling (like Sketchup)... there is no subdividing up or down (triangulation). You have what you have. However, NURBS and polymeshes can be taught of to have infinite resolution because they're recalculate-able.

From what I've heard with Rhino vs. 3DSmax is that Rhino is a lot better suited to handling NURBS and modeling with NURBS than 3DSmax currently is. That being said, 3DSmax whoops ass with poly meshes.

nurbs u work on overall shape with precisions like watches, car model...
polygon u work on individual faces on that shape like modelling human faces or architectural details...

it all depends on ur design, sometimes i use nurbs to sketch an overall shape then convert to polygon to work on details.

I also don't claim to be an expert, but here's my 2 cents:

each program will excel at something--and try to do some other things to compensate or compete w/ other packages: i.e. Rhino has mesh tools, 3DS has nurbs tools. It's true that in the end, everything is converted to mesh (rhino does this when you switch to shaded mode--and at render time--you control the accuracy/fineness of the mesh in the global settings). Depends really on what you're comfortable modeling in. 3DS max doesn't do accurate modeling as well, I have experienced--try snapping, or referencing other geometry, for instance--kind of a headache; easier to do in Rhino.

why nurbs? better control over curves from the start. The tradeoff: takes more care to keep your surfaces under control. Whereas in 3ds you can start w/ "dumb" geometry, smooth, and the algorithms keep things connected.

there's a lot shortcuts you can take w/ a "box modeler" like 3ds when doing orthogonal geometry, on a typical building for instance--ring selecting a bunch of faces and extruding, for instance, to get a quick offset (reveal)

"Despite that NURBS often lowers the amount of shapes necessary, in simple instances like an extruded pentagon... NURBS can add unnecessary geometry."

WTF? Wrong, if done correctly. When it comes to line work, nurbs vs. polygons makes no difference. (ie, when using nurbs to do polygon modeling).

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"When outputting any 3D data to be used in the real world (fabrication) or semi-real-world (video games et cetera), most things are incapable of taking NURBS as is."

Have you ever set up curve paths for a good CNC router?

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With current fabrication methods, it's really better to start off with nurbs and move to polygons if the project requires you to.

Draw me an extruded pentagon in NURBS (perfectly quadratic mesh too) that only uses 7 polygons (quads) and I'll LOL to the I'm-Sorry-I'm-Wrong-Bank.

With current fabrication methods, it's really better to start off with nurbs and move to polygons if the project requires you to.

That's uhh pretty much exactly what I said.

Everything is converted to a polygon mesh (which is essentially a triangulated surface). The advantage with working in NURBS or meshs is that the geometry is calculated through the polylines themselves.

In pure polygon modeling (like Sketchup)... there is no subdividing up or down (triangulation). You have what you have. However, NURBS and polymeshes can be taught [sic] of to have infinite resolution because they're recalculate-able.

actually, an extruded pentagon "in nurbs" is simply composed of 7 surfaces.

what's your point?

what are you doing, trying to use 3rd degree nurb curves to build straight lines?

My point? All quads, awww yeah.

gotcha. i was wrong.

Oh, I wasn't trying to be an asshole.

I've been learning how to do shit in polymeshes and NURBs even despite not ever really using it and or hating it. I was really more or less afraid that I was wrong because that would invalidate everything I've learned to date!

I do realize, however, polymeshes and NURBs are the way to go when it comes to computer-to-product fabrication.

But a lot of what I've read said that unless you have absurdly complex 'organic' surfaces in your architectural models, there is little benefit to using them in architecture.

Coincidentally, polygon modeling -- while great in general for architecture-- sucks for rendering unless you have a program that automatically does [turbosmooth] filleting/chamfering.

who still uses Rhino? isn't that trend over?

whatcha usin' olaf? I gotta get on that bandwagon!

@ olaf design ninja, I am very curious as well... what are you using?

Let me preface what software I am using with the following .
I first learned PovRay back in 94, then in 99 if my memory serves me correctly I learned a very early version of Rhino, then in 00 picked my first copy of 3dsMax V2 (discrete software company back then).
Up until max 5 NURBS was a Rhino thing and until AutoDesk bought Maya from Alias some animation things were better in Maya, granted Max's Reactor by Havoc is more true to physics.
I learned to script in Rhino 3 when David Rutten (reconstructivism) was all the craze and you used to be able to download his scripts, what happened? I also learned Generative Components once.

The new Slate material interface on Max 2011 looks just like grasshopper, which suggests someone will re-manipulate this interface for the sake of modeling.
And as far as Parametric design goes a guy name Ali Torabi has developed a great plugin for Max I use regularly.

I made an economic decision years ago when Autodesk bought Max from Discreet, then Maya, etc...I don't want to keep learning new software I want to learn the software owned by a company who has the funds to develop their software to do what all the other programs do, and that is Max.

Max has a new lighting analysis feature a friend will be testing with real lights and IES files against reality soon, light meter and all.

Also polygons not meshes is a big thing for me.

So there you have it Olaf is a 3dsMax guy.

But a friend linked me to the next big thing, ha - Creo

yeah, i disagree.

grasshopper + certain other plug-ins for rhino = fastest modeling + parametrics available at this point.

and if you really wanna script stuff, why waste your time with max when you can python it up with maya?

anyways, i'd still rather be using digital project. i miss that program a lot now than i'm a cad monkey.

Flixbound as you say - at this point
Never worked with digital project but a presentation of it I was giddy
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