PDA

View Full Version : Is it taboo to use Catmull Clark while modeling?


Amphitrite
06-17-2008, 05:06 PM
Well, since I'm rookie, I found a lot of problems to try to stick to "quads" while using Subpatch (for example, while trying to "glue" eyelids or mouth to a face), and because I readed that Catmull is able to render from tris to n-gons... Like I want to use it for easyness, or do I must to practice with Subpatch before I jump to Catmull?

I'm having a dylemma because I want to learn, but it is supposed that one must to learn first to add up before learning square roots... And I don't know if I might skip some important learning if I use Catmull directly just because it saves me from quad headaches http://www.spinquad.com/forums/images/smilies/confused.gif

What do you think?

toonafish
06-17-2008, 09:17 PM
forget about sticking to quads if there's no good reason for it. I say: try to focus on the important things first and that is the design and the end result.

If the geometry renders and deforms okay with tri's or ngons and you don't need to export to Zbrush or some other app that has trouble with non quad geometry I think you should not worry about it.

You will notice after a while when it's better to use only quads in certain areas, but stuff like that is easy to fix most of the time.

Personaly the only areas I try to keep free from ngons or tri's is the mouth area and the eye sockets. Simply becuase it's easyer to create morphs or weightmaps.

but you don't have to take my word for it, count the ngon's in Stephen Stahlbergs geometry: http://www.3d.sk/tutorials/Modeling_a_foot_in_Maya.htm
http://forums.cgsociety.org/showthread.php?t=108412

bobakabob
06-18-2008, 12:21 AM
Agree with Toonafish... though just to emphasise the point about ZBrush it's probably a good idea to work in quads to start with as if you incorporate this app into your workflow you can run into problems. Plus LW subdivisions seem so much faster in Modeler than CC.

proton
06-18-2008, 02:15 AM
I would avoid anything but Quads in areas that are going to deform...it's your safest bet IMHO. I shoot for all quads and if I have any tris I limit them to areas that no one will see.

biliousfrog
06-18-2008, 08:40 AM
I would say keep to quads, it will help you with your topology in the long-term. Trying to break a bad habit is difficult and using n-gons for sub-patches is a bad habit and unneccessary...many people started using n-gons when CC was introduced and earlier when Modo was released, not because it has any benefit but just because they could and it's less effort. I won't say "never" use them but I've never needed to use them and haven't known anyone worth their salt using them either.

toonafish
06-18-2008, 10:58 AM
use them but I've never needed to use them and haven't known anyone worth their salt using them either.

Wow, I think you need to make a small adjustment to your statement here. Or are you implying that Steven Stahlberg is not worth his salt?

ThE_JacO
06-18-2008, 11:07 AM
won't say "never" use them but I've never needed to use them and haven't known anyone worth their salt using them either.

I've seen accademy winning and accademy candidate work that used ngons.
The whole quad thing has its reasons and its place, but most people don't even know where it comes from or how it came into being.

I've seen people preaching all quads pimping some techniques, like making a triangle into a quad by just dividing one side and adding an edge loop from there, that are nothing short of extremely retarded. They were even proud and had their own name for such things, and boasted how it was handed to them (as a trick) by this or that famous person.
Go and look up baricentric coordinates (the fundamentl of a lot of things like UV interpolation) and see what a tri shaped quad resolves to.

You're much better off with a triangle or with a convex nGon than with a triangle shaped quad or, even worse, with one that will deform from convex to not.

I'm not saying a good flow isn't important, but the whole subject is grandeously misunderstood and mis-promoted by people who have not the faintest clue about it.
nGons and tris are perfectly fine, especially if you use a subdivision surface algorithm that doesn't suck like Catmull-Clark or Doo-Sabin. You just need to know what you're doing, pretty much like with everything else :)

toonafish
06-18-2008, 12:03 PM
Thats the spirit !!

:beer:

biliousfrog
06-18-2008, 12:41 PM
OK, I admit that I might have been a little hasty but, in general, most of the people using n-gons with sub-patches that I've experienced are doing so because they need them to patch something that a good topology would have avoided.

Of course, other 3d apps have had n-gon support for some time and apparently they work out ok. I'm just talking from personal experience with Lightwave which is a little less forgiving for certain things. Funny thing is, I was discussing this with a client only last week who explained that a freelancer they used came from XSI and used the worst topology they'd ever seen...it was fine in XSI but using CC's in Lightwave caused them a load of problems.

...and that goes back to my previous post that the software shouldn't be used to make up for poor topology. It's a little like taking crappy photo's because you can touch them up in photoshop, it doesn't make you a good photographer.

toonafish
06-18-2008, 02:06 PM
Of course, like I said in the beginning, if the geomety looks crap you have a good reason to make a change. But that does not mean that ngons and tri's should be avoided at all cost.

You're not advising everyone to walk around in a rain coat all the time, just because you know this guy that didn't and got wet, are you ? ;)

Amphitrite
06-18-2008, 05:59 PM
Woah *shivers* I am scared (because I have n-gons on mouth and on eyelids place - but guess I can fix this in a second, or two...).

Thanks for all these inputs. It is always nice to know more about particular techniques and why some things are avoided or not normally used for long-term plans (like planning an animation and such). Personally, the model I'm doing will be rigged and animated, as to full complete my practice with all the tools the program have to offer (now trying to realize for what SpinQuad tool is used to). It is a cartoonish character but I guess it is good as a start.

Will check back if someone have something else to add to the topic from its experience with this program and compatibilities with other tools (such as Z-Brush being unfriendly with N-Gons).

CGTalk Moderation
06-18-2008, 05:59 PM
This thread has been automatically closed as it remained inactive for 12 months. If you wish to continue the discussion, please create a new thread in the appropriate forum.