SUBDIVISION DISCUSSION

[rage]

OKOKOK, i will start a thread that may interest a lot of u guys....subdivision modelling, this technique has a lot of tips & tricks of the trade, and as i saw in these forums it is used by many of the people here....so maybe it starts a nice and neat discussion about this way of modelling things...

"the way in which a subdivision surface is derived from a low-resolution control cage"

this could be a definition of subdivision....although it may be a bit short...hehe

Subdivision is a way of modelling in wich u define a low resolution control cage wich is later subdivided by a smoothing algorithm based on, or similar to Catmull-Clark subdivision surfaces.

I want to start a deep discussion here so lets start...

What is sub-d?
what are its rules? can we break them?
where do i start?
Cani use sub-d to model ANYTHING?

etc...etc...etc...

Lets start with a good ol trick wich i learned a few weeks ago and i will give some examples....

My balrog axe.... I wanted all on the axe to look beveled, so i cranked my head and went nuts....but i ALMOST get it...i added so many segments that now that i look upon the mesh topology i laugh...hehe, have a look:


almost.....looks like crap aint it...there are places where some edges are missing and some where they are to many...can u spot them?

BUt when i did that, i didnt knew of this little trick....hehe

imagine u want to do a beveled box using sub-d....
how would u make it????
lets seee...."I would make a box, chamfer all the corner edges and voila!"
well that would be a good way...but imagine u want to make an L shaped part with that box later extruding one of the sides....it would be a mess once u apply meshsmooth...hehe

So i got my hands on this awesome yet simple technique....have a look at the images...they are self explaining:
[NOTE: on the last two images , the wireframes are unsmoothed]







WOOOOOW!! jajaja... machanical beveled objects on demand!!!
Just by adding one edges on each side of the one u want to get beveled and its done!!
Here:



Of course this isnt mention to teach how to do beveled edges is a way of comprehending how sub-d´s work, hope it helped....

well, this is just one of the techs there is...i´ll post some more later...and of course this is a forum so i expect someone posts theyre own and also make commenst and such...

Lest start the debate, and please share your secrets!!

cheers!

[Kit]

Cool thread!
I might be getting a bit ahead, but I want to post my favorit sub div tip before anyone else does!
(Since I use Max, I´ll write it in Max terminology but I´m certain that the same can be achived on any self respecting 3d program)

While working with the low poly version create a reference of the object and apply a meshsmooth modifier to the reference. Now you can work on the low poly version and you can see the end result at the same time! It´s a lot cleaner than working with "show end result" activated on the low poly versionand if you hide the objects you are not working with it might also take less CPU resources.

Happy modelling!

[pkbanana]

nice thread thanks.
do the above methods work in this situation?see picture
this is my problem, trying to attach the head to the body.

[rage]

Use the pattern shown in the attachment for local detail termination...

BUT...such a mesh topology will bring u problems once u animate, because the neck isnt a good part to break edgeloops...hehe
try and subdivide the neck down and terminate the detil after the neck finishes...this way when the neck bends it will look correctly...
oH and by the way for the next char u make, some advice...try and have conggruency whan u mopdel separate parts that are to be attached later!...hehe so u dont have to do this again....

[pkbanana]

great tip rage thanks!!!

Excellent walk through the basics:
http://www.erikasorson.com/tutorials...bdivision.html

Tamas Varga's excellent sub-d page:
http://maxrovat.sns.hu/subdiv/

Advanced discussion of edge loops & tecniques (by Bay Raitt,):
http://www.izware.com/news/indexa446.html

Sub-d modelling deity, Bay Raitt's site:
http://cube.phlatt.net/home/spiraloid/
His sub-d forum - lots of good topology discussions etc here(if you are going to join, PLEASE read the rules or you will be thrown off.):
http://cube.phlatt.net/forums/spiraloid/index.php

Wiro's site - excellent modeller & best box modelling head tut on the web imo:
http://www.secondreality.ch/

Sub-d modeller Martin Krol's site (also some video tuts here):
http://ambient-whisper.cgcommunity.com/
Face modelling & setup by Martin:
http://ambient-whisper.cgcommunity.c...al/Page-1.html

Head edge loop layout tut for lightwave, (but everyone could apply it in their software):
http://www3.sympatico.ca/tayse/style.htm

Head topology discussion on cgtalk:
http://www.cgtalk.com/showthread.php?s=&threadid=38469

Free sub-d modelling package, wings 3d. More powerful than it looks:
http://www.wings3d.com/

Meshtools for max. The original & still the best. Max 5 incorporates a lot of the originals but there is still version 2.5 for max 5 that has some stuff that was missed. For max 4 it's absolutely necessary. The meshtools site is down at the moment but you can find the scripts here:
http://www.scriptspot.com/start.htm

MJ polytools for maya & max:
http://www.maya3d.dk/Scripts/MJPolyTools/

CS polytools for max:
http://www.3dluvr.com/subagio/cspolytools.html

Nice thread Rage- gonna make this thread sticky. If someone else wants to start a similar one for nurbs or splines etc, go ahead & I'll sticky that one too.
Have fun...

Animated gif - worth a look:
http://www.bunk.cistron.nl/plaatjes/buildup.gif

Discussion on what does & doesn't constitute sub-d's. Interesting stuff:
http://www.scifi-meshes.com/forums/s...=&threadid=320

[rage]

hehey! a sticky threaad! cool thanks mike! I absolutely knew that i was counting with your support! hehe

i gathered some other links following some of the on eu posted.... here they are:

FAcial sculpting and setup

articulation of mehes for animation
this one is ay cool and i suggest that u link it on the front pages

will be back later...cheers!!!

[rob_beddall]

hey!!
pretty much the same tip as kit but, .... if you use maya, download the connect polyshape plug-in. you can then have 1 half of the model with 0 sub-divisions and the other half with a smoothed version. this is how i work and it's quite good and fast.
connect polyshape also has lots of other cool features.
cheers!

[Incitatus]

Here's another little problem which I'm sure we've all encountered. How to add edges while maintaning curvature?

(Without moving every single vert, hmm a sphere would have been a better example)

(sorry for low qual jpeg hope you get the idea )

[rage]

i guess u must relocate the segments in order to get the closest possible to the original curvature....like this

[kuman]

there are certain ideas about poly modeling that a lot of artist think are rules written in stone which i tend to disagree with. you have the idea about keeping quad, preserving edgeloops, and modeling with as few poles as possible.

poles well poles are will happen, if you extrude you'll have poles, i don't think there's more to discuss than that really.

the idea of keeping quad is based on the fact that quads smooth better (this is a hazy point to me, i've seen plenty of examples where quads smooth no better than tris, this smoothing issue seems (imho) to be more based on planar angles than necessarily the shape of polys) and that they set up a regular division for animation.

in modeling a lot of cloth recently i find that keeping quads was something that really wasn't an option. its easy to keep mostly quad and complete edgeloops in a more regular form like a forearm or even a face, however i've found when you try to model a more chaotic system like cloth where shapes change dramatically in fairly small distances then keeping quad and full edgeloops becomes really a luxury. sure you could do it but you'd probably spend as long just fixing your polys as you would laying down the fundamental shapes themselves. in this instance i would say flow lines are the most important things. as a matter of fact in my own work i've found that the idea of a flow line seems to dominate my list of important things to keep in mind when modeling, so much so that keeping quad and full edgeloops have become secondary to having good flow lines.

the flow lines are basically edgeloops in discussions by bay raitt and martin krol, i just hesitate to call them that because to me that term carries some baggage with it, ie running in length as far as possible or returning all the way around to form a full loop.

anyhow i took some of wip shots of wireframes and outlined what i saw as my flow lines during modeling. some people have written to me and told me that my wires for cloth seem crazy or completely without order. well it really isn't crazy or chaotic in my eyes, there's actually a method to the madness and its in the fact that i don't really see the edges but the flow lines. here's a few pics of what i mean:



i guess what i'm saying in the end. my tips is to not get too caught up in the "rules". not every surface can be described the same way. imho, the key to modeling a surface accurately is to get a feeling for how it moves and how it flows not how you can form it with all quad polys.

happy modeling

-k

[goat]

Great point you got there Kuman. I myself tend to stick stricktly with quads but found more recently that as long as things are"flowing" it's ok to bend the "rules". Grewat models by the way.

I'll try and get some tips this weekend if I get some time.

Mike nice sites.

Rage great idea for a thread

[Zytrex]

Hi Kuman, nice work there. I'll keep that in mind when modeling.

Hey Rage, sorry I haven't had a chance to give you a visual demonstration of the problems I was talking about in the other thread, as far as mesh banding and stuff like that, but I've been very busy. In fact, I'm stll busy, so I guess you'll just have to keep waiting!

[pencil_head]

can anyone explain when and why it is usful to use the "keep faces convex" button in max.