Poly Smooth Vs. Subd And The Right Way To Work

[aofer]

hi, i'm relatively new to maya though i've tried a few tutorials already.
anyway in all of the tutorials that i've done, i used SubD objects and worked on their polygon mode and then tested the results in their standard form. i tried a few tutorials from digital tutors which seemed excellent.
anyway i started learning maya a month ago in IAC (israeli animation college) and our instructor said that people rarely use nurbs and Subd in maya because they are unpredictable. and instead we should work with poly smooth using the poly smooth proxy method.
the whole thing didn't seem to make any sense because i see alot of tutorials which uses SubD so i asked again and he said that SubDs in maya are not a Production tool and though it seems like a really good way of work, after you reach a certain amount of detail the model becomes really heavy and it really slows the computer, so instead i should stick to the method of working with a proxy.
the two methods seems kindda close to each other. but the proxy method of working on the low poly object while looking at the high-res result which you usually set as reference seems a bit annoying.
anyway i was wondering if i should really try to avoid converting to SubD and try to get along with poly smooth? is this the best way to model high res objects? because in lightwave for example you gotta use SubD because you don't have the poly smooth thingy.
and my second question is whats the main difference between SubD and Poly Smooth? cause i still haven't figured it out.

oh and one last question, i know how to set my units in the settings menu, but the units in maya are general units, so how can i set one square on the grid for example to be 1 meter or one inch, and can i make the grid bigger?

i know its alot of questions, but i would really appreciate it if someone could take the time to set things straight for me.

thanks in advance,

aofer

[fortner_mike]

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i tried a few tutorials from digital tutors which seemed excellent.

Yes indeed
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our instructor said that people rarely use nurbs and Subd in maya because they are unpredictable

That's really weird. People use sub division surfaces and nurbs equally or even more then polygons(well technically you always work with polygons even if you control them using NURBS, but it doesn't really matter)

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they are unpredictable

Hmm, well so is maya if you dont know what you are doing

The idea of working with subdivision is that you can use the features of nurbs and polygons, you can make smooth or hard surfaces using creasing. Also its a good way to add detail to objects and to make your blocky model into smooth surfaces.

I'm not that much into nurbs, but i know that they are great as well, for particular tasks.

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after you reach a certain amount of detail the model becomes really heavy and it really slows the computer

Yeah thats true. But any kind of models eventually will slow down your computer. Thats why you have layers. Subdivision surfaces really are the most "heavy" so i like to either hide them in layers or convert back to polygons when i'm done (sometimes if i need to see exactly how it looks, but i also need to have it in sub-d mode i just create a temporary polygon copy and hide the real sub-d surface). Or, like your instructor said, work in proxy mode.

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anyway i was wondering if i should really try to avoid converting to SubD and try to get along with poly smooth?

Hmm, poly smooth is really much less predictable then subdivision i think. Or at least less controllable.
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is this the best way to model high res objects

There is no best way, you have to find what works best for YOU. If your instructor want's you to work the way HE does, than i think thats not quite right. What you should do is try and understand how maya works and what does what, not to learn working someone elses way. Bu then again, your teacher might show you something that is really good and that you could use in your creative process

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hats the main difference between SubD and Poly Smooth?

In essence I think subdivision has much more control than smooth.

I'm not sure about the grid, i dont really never model something that accurately so usually turn of the grid.

[joojaa]

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hats the main difference between SubD and Poly Smooth?

The subd has a limit surface the poly smooth is still a poly. As such when you dice up the render then the subdiv and nurbs use the real position while the smoother poly uses the position on facet.

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our instructor said that people rarely use nurbs and Subd in maya because they are unpredictable

Well if that would be the case they wouldn't be used. in all actuality smooth normaled polygons are unpredictable, because they represent something that they aren't.... Anyway dont beleve everything your being told.

I dont think many people have given this fact a very deep thought, wich leads to the entire haste with booleans and normal interpolation artifacts. which is also the source of the limitation in both nurbs and subd surfaces.

So in way subdds and nurbs represent what is at the cost of how it looks whereas polygons represent what looks at the expense of what is.

Anyway subidvs aren't necessarily heavier then polys, in fact they are as light its just how you choose to build your history chains thats at question here. So you can get all the benefits of sudivs with the same cost as polys IF you are smart about it