[bjorn.syse]

Hi everyone,

I wanted to discuss the differences in modeling workflow/approach with using a subdivision modeler vs a NURBS package. I'm sure this has been dealt with before in numerous fora, but I'd like to put the industrial design perspective on it.

Let's say I'm an industrial design department that is on the way to invest in 3D-technology for inhouse concept design. Basic rendering requirements. Our construction department work in SolidWorks, but we're mostly going to use our 3D-package for concepts in the early/middle stage of the design process. Should we invest in a NURBS package like Rhino, or go for the subd-approach with for example Modo?

Would you agree on the following points? Feel free to add or subtract.

NURBS package
-------------

• Can be compared to vector graphics. Are mathematically defined, and resolution-independent.
  
  A setup of numerous tools that has well defined tasks is used to model different type of geometry, that are put together to a whole.
  
  + Better control over parameters such as hole diameters, fillets radii etc.
  + What most Industrial design students are taught. (Will help with future employees)
  + The same kind of hight quality geometry used by CAD-programs, which can save time later down the product development line.

Sub-D package
-------------

• Widely used by the film and computer game industry for character modeling.
  
  The same kind of tools are used to push, pull and modify a "lump" into the desired shape
  
  Can be compared to pixel graphics in the sense that the resolution/the number of polygons define how smooth the surface will look
  
  - No control over parameters such as hole diameters, fillets radii etc.

I'm just trying to bone out the differences for them to beeing easier to explain to people not familiar with any of the techniques, but still need to decide which one to go with.

- Björn

[knurrebusk]

I understand your pain!

The moment Autodesk ant behaviour join with free thinking life is good for all of the great minds out there that do not need ,.-

Inventor is perhaps the golden mix, but Autodesk will do it´s best to make money.

This is a poor man´s Gehry tools, so we should be happy! right.
I´m not sure if this holds trough.

[knurrebusk]

Forget to agree big time!

Great topic, that still challenge minds all over the world.

[mverta]

For dark is the suede that mows like a harvest!


_Mike

[lebbeus]

Rhino would work well in an industrial design setting, but it needs a renderer (maxwell, brazil, vray, etc.) and each seat is under $1000

Alias Studio on the other hand has some interesting features, incorporating conceptual sketching tools and nurbs modeling, plus I think it has mental ray built-in (though I could be mistaken) the downside is: it's VERY expensive starting out around $4000 and reaching somewhere around $13,000 depending which flavor you get. Then there's the questionable longevity of the product: will Autodesk phase it out in favor of its own Inventor or not?


I think your explanations about the differences between a nurbs modeler and a poly modeler are spot-on and I'm probably going to use them the next time someone asks me

I'd go the CAD route, as it should eliminate potential headaches when outputting files for CAM compared with trying to get watertight models from a poly modeler.

[Sheik]

There is some useful info in the difference between Sub-d and Nurbs here:
http://team.subdivisionmodeling.com/page2.htm#about

In general you could say Sub-d modellers give you some more artistic freedom in the workflow. That is basically due to the box-modelling approach, which is possible in these polygon modellers.
http://team.subdivisionmodeling.com/page3.htm#box
But what you create is a polygon mesh, so that will not be so useful your SolidWorks phase…

The new T-Splines plugin for Rhino now makes that same way of working possible with Nurbs, so the difference in workflow is not that big now.
http://www.tsplines.com/

For industrial design and manufacturing I would chose Rhino+Maxwell.
(I have both Rhino and Modo).

Or if you want a lighter Nurbs solution try MOI3D. (http://www.moi3d.com)

Sheik

[codygo]

I started off with alias studio in version 8 and can say it definitely has better controls for surface continuity (g0,g1,g2,g3..) than rhino, and other modelers simply don't even have that kind of control. It also has much better history than rhino has at the moment, making the development of surfaces easier than in rhino, especially with regard to flanges and fillets. AliasStudio has nice hardware realtime rendering, and you can draw within the program. Now if you don't plan to machine your parts from these models, and just use them for visualization and some photoshop postwork, then these features aren't as important.

That said, rhino is simply more affordable, and it can render directly to maxwell and more. Given enough experience, and for ultimate control of surfaces, you simply don't end up using much of the fancy features in autostudio because you'll have to break history to manually tweak the cvs to achieve high levels of continuity. Ideally, by the time you start working in 3d, your model is pretty closely defined in sketches anyways.

Another selling point for rhino is it opens and exports a great deal more filetypes than does aliasStudio.

[bjorn.syse]

Thanks all for your comments. Some of them were more vague than others

Thanks for those links Sheik, they were very useful. Wish some of those Box modeling videos worked though. Say, have you ever ran across any as explaining pictures describing the NURBS approach?

Leebues, codygo, I agree on Studiotools having better control over surface modeling and continuity. I've used Studio since version 12 came out, and I just recently switched to Rhino. I have very little experience with SubDs but still want to give a fair comparison.

I can see the It is generally excepted that modeling in Sub-D's is freer and more fluid than with splines.,. but what is the downside of this, except beeing stuck with a polygon mesh afterwards?

Are there different things, like revolves or dealing with standard components or, something one should think about?

Third, am I right in the assumption that most industrial designers lear NURBS?

- Björn

[Maximus3D]

Björn, as i think the other guys already said. Nurbs is the way to go if you're gonna work with the rest of the team that uses SolidWorks as SW can import Rhino files (i read that it can, but can't confirm it).

Also it's kinda a mess to edit a fillet or chamfer when you model with polys, or in plain english it's a freakin nightmare to edit them as you have to rebuild quite alot of your model, depending on what your model looks like.

It's also easier to get started with nurbsmodeling, especially if you never done any polygonal modeling. The advantage of polygonalmodeling is that you can easily UVunwrap and map and texture your models, this is a bit more messy with nurbs as they kinda lack UV's until you polygonalize your models.

One thing you should look at if you're going down the nurbs road is Moi3D, it's deadcheap and great! you can quickly sketch your models there within a few minutes and then move them over to Rhino for detailing and fine adjustments. Also if you're gonna export your nurbs models to polys then you wanna use Moi3D for that since it has a much better and more powerful exporter module (you will end up with better polygonal distribution and fewer polys on your exported models).

Have you got any experience or knowledge of polygonal modeling at all Björn ?

Btw, if you're gonna invest in a polygonal modeler make sure it's Modo302, anything else sucks!

Hope you will make a good decision.

/ Max

[bjorn.syse]

Hi Max, I was sort of waiting for you to catch this bait! I know you're a heck of a skilled modeler and from what I've seen you seem to master both the two techniques.

First of all, the only experience I have in polygon modeling is what I've learned while trying SILO, just to being able to master T-Splines even better. Since, T-Splines are based on SubD I figured I'd be better off learning where they came from.

Secondly, I'm trying to help a customer that represents a company with this decision, and even though I personally would recommend them Rhino since that's what I can help them with the most, I wanted it to give them of an objective comparison so they can make an informed decision.

Do I get you right if you think that NURBS would be easier to learn if you've never worked with 3D before? except a few turns in SolidWorks but ending up not using it because tha gap is too big between what you want to do in your head, and how quickly or easily that can be modeled. I think that is the case for a lot of these people.

How about speed of modeling given that you've taken the time learning any or either of the techniques?

- björn

[Maximus3D]

Hehe Björn thanks for those very kind words. But i wouldn't stretch it that far and call myself a master of either of those modeling techniques. I know how to use them both, which most people do..

With that experience you got from Silo and T-Splines then you already have plenty of knowledge. Somehow i got the impression you needed help with this for your workplace, doh! sorry for my misunderstanding. But it doesn't matter.

In a way nurbs would be easier for a newbie to start with, but Rhino might be a tough bird to swallow as it has a gazillion buttons and written commands you need to learn and all that could scare away even the most experienced of modelers, just think about them poor newbies.. however, here's where Moi3D yet again slips in on a bananapeel as it's ALOT easier for newbies to get started with when you're going to be introduced to nurbs and solidsmodeling, you'll get started with it within 10 minutes. The step from Moi up to Rhino will be a smaller one for them.

And you have full fileformat compability between Moi and Rhino, this also helps users in their workflow and learning process.

As you probably already know that when you work with polys you have to try to keep in mind edgeflows and all that stuff. Mess those things up and your model might be ruined just like your workday. And stuff like that is not really easy for new users to learn, it takes quite some time until you learnt everything there is to know about polygonalmodeling.

About speed of modeling once you master both nurbs and polys, hmm.. i have to say nurbs is faster, you can quickly rough out the shapes you need, slap on a few fillets and chamfers, measure it up, tweak it, drill some here and there and then you're done. Try doing all that in a polygonal modeler at the same speed as you can do it with nurbs.. good luck! you gotta be a bloody fast modeler to pull that off with polys.

In the end i would have to say it still comes down to what the models will be used for, how they will be used, how fast they need to be produced, the skill and will to learn new things of the staff at the office, the budget, if there's gonna be compability with SolidWorks which i assume they want, if they will be animating their models and much much more.

What type of models are these people gonna build ? will they be manufactured from those models created ?

/ Max

[yanada]

And yes max did put things into perspective once again.

[yanada]

[Leonardo]

where is el nurbaitor-dim0 when we need him...

[knurrebusk]

I´ve tested most of the software out there, just for the single goal of putting a free-form/curved sketch on a bended nurb´s surface, then translate this to solids.

I´m perhaps stupid, but the software that can do this is stupid too!
Very limited in acces for young people.