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athena
04-09-2007, 07:27 PM
I'm taking an online class right now from CG Society (http://www.cgsociety.org/) on Low Poly Character Modeling. This kind of 3D modeling is what's used in video games, but also really good if you plan on animating your finished characters on your home computer... since really, it's not likely that you'll have a render farm behind you to create your finished film.

I can't really pass along everything that we're presently learning... it'd be overwhelming... but I thought maybe I could drop in a few key points. Such as...


#1 Good Animation Begins with a Good Model

The two images that I attached to this post are "Marina the Fish Girl" (aka the *bad* model) and "Sir Stumpy" (aka the *better* model)... you'll note that I don't say good model, because if I were to do him again I'd probably make a few changes... but he's a lot better than Marina.

Marina was the first character I ever modelled. She renders reasonably well, but when it came to animate her... let's just say it wasn't pretty. That's because when I modelled her I was modelling for look and not the ability to animate.

Look at her face and then compare it to Stumpy's face... Stumpy's face, although a little hi-poly, has edge-loops around the eyes and mouth... this provides the geometry to spread out evenly when the eyes close and collapse with the right sort of creasing when the eyes open. Now look at Marina's mouth and eyes--no edge loops... I quite literally cannot open her mouth ever, otherwise her face would snap in half.

This is what I mean by modelling with animation in mind... you lay into the model where you want the joints to be... what will stretch, what will bend... it can't just look good, because if you model only for looks the minute the character moves it's likely to have all kinds of problems.


#2 Watch Your Poly Count

Now, I'm going to have to disagree with Great Dragon on subdivisions here... both of these characters I've attached are subdivided once. When you subdivide--to create a smoothed look--you are adding to the poly count and making the computer work much harder to do its renders. This is particularly true when you're animating.

Marina for instance is...
19,000 polys before subdivision
37,000 polys after 1 subdivision

...this is all that is really needed, but if you really drive the poly count up

102,000 polys after 2 subdivisions
368,000 polys after 3 subdivisions

...even the act of subdividing that high causes my computer to slow down.

Another way to think about it is I could have ten characters of Marina's level of detail in the same scene for the same amount of computer rendering oomph as a single super subdivided version of Marina.

You want to keep an eye on that poly count because when you make your animated film, you are bound to want to have more than one character... and a set... and lights... and lots of pretty colours and textures... you need to spread the load around and not bog down the computer on a single character.


Now, when I say that these are good, but definitely not *great* models, I'm largely referring to poly count... Stumpy is 91,000 polys and if I were to do him again, I'd try to drive that poly count WAY down. When I was making my short film with him, it was very time-consuming to rig/weight him and there were times--particularly after sets and everything else were in place--when the computer really started to grind... and this is not a slow computer by any means, this is a fast, dedicated animation machine with $1000 video card, lots of RAM and plenty of hard drive space... but still, you have to spend those polys wisely.


That's all I got for now... I'll add more as my class progresses. :D

The Great Dragon
04-10-2007, 11:00 AM
The reason I subdivide with three iterations is because I tend to model with far too few polygons. For example, I only had 4,000 polys on my dragon before smoothing. And, my film will be live action, so I will only have three or four such subdivided characters.

athena
04-10-2007, 11:46 PM
The reason I subdivide with three iterations is because I tend to model with far too few polygons. For example, I only had 4,000 polys on my dragon before smoothing. And, my film will be live action, so I will only have three or four such subdivided characters.

I still don't think you need to subdivide it three times. 4,000 is a good number of polys--plenty to work with... it's the kind of poly count I would want to drive Stumpy down to if I could.

The problem is that when you subdivide you're adding excess polys to areas that don't need them... areas that are probably already smooth after the first subdivide... if it's taking three subdivisions to get the look you want, it's probably an issue with the wireframe--tweak a couple polys and you wouldn't need to go that high.


Just an idea... post your wireframes--no subdivisions, 1 subdivision, 2 subdivisions, 3 subdivisions... I might be able to give you an idea what I'm talking about.

The Great Dragon
04-11-2007, 09:07 AM
OK. I scratched my old model for the umpteenth time... Okay, I'll post a few WF's. I think two iterations might be enough, now that I see three is incredibly dense. I always had isoline display on.

My dad wants to get us a far faster PC for rendering, a dual core 64 bit processor, and just put Max and Vegas on it. (Sony Vegas is my editing program). If only I had a render farm...

(BTW, this model isn't finished, so it has less than a thousand polys, yet it is higher than it would usually be.)

*edited to add a non-wire frame one with three iterations. I need to get rid of the wrinkles on the neck, though...*

athena
04-11-2007, 10:45 PM
Okay, looking at those wires I can say right off, that that three iteration one is insane... it's practically white because the polygons are so dense... two iterations isn't much better, honestly the only time I'd recommend that density of mesh is if it were a piece being used for cloth animation... eg. something like this (http://sirstumpy.com/lj/skirt_carpet.avi)... there has to be sufficient polygons to bend and flex in a realistic way... if cloth is too low poly it tends to crumble in a very angular way and thus it's much less realistic.

However, your dragon isn't made of cloth, it is made of flesh... and flesh and bone are firm... your dragon moves the muscles shift in predictable ways such as at the joints, but remains much more rigid between the joints. If anything, I think your model suffers from being too "mushy" and that's also a result of too many subdivision iterations.

Trust me... you can achieve the look you're going for in *one* iteration.

Don't believe me? Best modeller I know is a classmate of mine... way better than I am... and just look at her models...

>> body - shaded (http://kristychapman.com/gallery/girl_body_a.jpg) and wireframe (http://kristychapman.com/gallery/girl_wire_a.jpg)
>> legs - shaded (http://kristychapman.com/gallery/girl_legs.jpg) and wireframe (http://kristychapman.com/gallery/girl_wire_d.jpg)

The problem with subdividing is that it increases the polys eveywhere instead of smoothing just where you need it. Look at the toes... to get the wrinkles around the toenails, she models in only what detail she needs... if you look at the lower leg there are fewer polys because she doesn't need them.

Of course there's also nothing that says you have to model in the wrinkles--really fine detail like that can sometimes be handled in the bumpmap... if you look at the attached image, the face on the left is just the shaded version, the one in the right is with the bumpmap. I imagine you used a bumpmap to add scales to your dragon, but you can see I've used mine to add the wrinkles into the forehead and on the bags under the eyes. I can be much more subtle than I could trying to model that sort of detail.


Now, if you're game to learn... zoom in on the areas of the model that you aren't happy with after one iteration... show me what it looks like unsubdivided and then with the one and two iterations applied... I might be able to offer you some suggestions.

The Great Dragon
04-13-2007, 09:42 AM
Yeah, that is quite a daft number of polys. For my 4,000 poly model, 3 iterations is 216,000 polygons (still not as many as Marina with three iterations). My problem was when I did a connect edges, it never turned out right. I shall try again. It's a bit early in the model to post more images.
As for bump mapping, I do use that, except it's kind of hard to get the bump map right on a complex madel like mine, and still have room to make all the other things look natural. I'm going for photo-realism, since it isn't a totally animated feature. Yet, some parts will be all CGI, and I'll have to use crowd control, because I'll have a large number of low-poly dragons all together. I'll probably animate different layers of THOSE separately.
One of the hardest problems I face is lip-syncing. Yep, they can talk. Another difficulty is casting, they have pretty diverse voices, the commanding voice of the Great Dragon (I wonder what my username is referencing...), the thick, deep, gravely voice of Darius, the mid-deep Australian accented voice on Skardek, and Michaelangelo's voice, that only one person I know has, but he refused the job. Darius, Skardek, and Michaelangelo are really the three stars (along with their human "mates", if you will, me and my two best friends)

The Great Dragon
06-29-2007, 07:10 AM
You should see this guy's portfolio-amazing!

http://www.zivcg.com