Essential LightWave 3D- P11 pptx

I don’t because I like to get the numeric info of just how many points were nated when I merge points manually.Because our spline cage was created bymirroring, our patches should fit per

16 Now, working with the curves that

define the rubberized bumper and the

opening on top of the kayak, select the

curves in the order shown in Figure

13-16 Fill in the Make Spline Patch

window with Perpendicular set to 10

segments distributed WRT Length

(for a nice, soft feel to its silhouette)

and Parallel set to 5 segments

distrib-uted WRT Knots (so the bumper’s

segments will line up perfectly with the

segments of our kayak’s opening)

17 The resultant patch may look pretty

angular as it skirts the rim of the

kayak’s opening, but I’m planning on

using this as a sub-patch model, so it’ll

be fine (Notice how the segments of

the bumper and the opening line up

perfectly.) Assign these polys a surface

appropriate for a rubberized bumper,and copy and paste the bumper ontoyour assembly layer

Note

Wouldn’t it be nice to be so brilliant that you know exactly what every setting does at every turn? I’m pretty far away from that myself To get the above settings correct to match the bumper up with the kayak’s opening, just like anyone else, I had to play around with it a bit until I found the right

settings Still, I didn’t trust it just looking

right I tested it, copying both patches to a

“junk” layer and using Merge Points to see if

it fused the two sections together.

No one’s perfect Don’t bust your chops if you’re not.

Figure 13-16

18 Selecting a few polys from the nose

sections of our kayak and using Select

Connected quickly selects all the polys

we’ll need to mirror to become its tail

Mirror those polys across X=0 (You

may merge points if you like I don’t

because I like to get the numeric info

of just how many points were nated when I merge points manually.)Because our spline cage was created bymirroring, our patches should fit per-fectly by mirroring as well

elimi-289

Figure 13-17

Figure 13-18

19 Mirror the entire kayak across Z=0,

and then merge points

Figure 13-19

Figure 13-20: Our completed kayak, surfaced and viewed as sub-patches!

.

That wasn’t so hard, was it? There are

many applications where using spline

patches can be pretty nifty

The hardest part about spline modeling

in LightWave is juggling the settings in

your mind so your patches end up seaming

properly (It’s a little like that children’s

game of memory — but it’s not cheating if

you want to use pencil and paper.) Just

know that it may take a couple of tries to

get things to line up

Also, remember that you’ve got to watch

the distribution of your knots You can do

some pretty fancy tricks through creative

placement of those little things Be sure to

weld all your endpoints (This is a simplething, but it still slips by me from time totime.)

There you go To quote Obi Wan Kenobi,

“You’ve taken your first step into a largerworld.” At the time of publication, only anestimated 4% of LightWave users said thatthey understood spline patch modeling Youcan take pride in knowing that you’re actu-

ally ahead of the pack! And to solidify your

position there, we’re going to exercise yourknowledge of splines by using them tomodel a human head Flip the page and let’sbegin!

291

Spline Modeling

Exercise 2: Modeling

a Human Head

Splines are a wonderful tool and I hope

you’re beginning to see just how powerful

they can be Splines are most often used to

model objects with large complex surface

areas, such as vehicles and aircraft In this

chapter, we’ll be looking at a more esoteric

use of splines, namely for the creation of a

realistic human head model

This chapter will provide a detailed

explanation of the process It is a long

chap-ter, but don’t let that intimidate you Each

step is broken down and discussed in detail,making it easy to follow, even for newusers That said, however, I expect you tohave already worked through the previousmodeling chapters and to have a basicunderstanding of the spline modeling rulesoutlined in Chapter 12

We’ll get into the actual modelingshortly, but first let’s talk about the thingsthat make a good head model

Figure 14-1: The head model built in this chapter with textures applied.

Poly Count and Flow

I’ve seen hundreds of head models and

doz-ens of tutorials showing how to build them

There are as many techniques for building a

head as there are people building them But

regardless of how the head is constructed,

there are two inherent qualities it must

pos-sess in order for it to be “successful.”

Contrary to what you might think, looking

good is not one of them Rather, the most

successful head models are those with a

reasonably low polygon count and an ideal

polygon flow

Poly Count

The best modelers are always striving to

create their objects with the fewest number

of polygons possible This isn’t just an

obsessive-compulsive drive It’s a practical

quest The more polygons an object has,

the longer it will take to render Even with

the most modern processors, a high-poly

sub-patch object will hit the render engine

harder than a low-poly object But the questfor minimal polygons isn’t just about rendertime It’s much more practical than that.You see, when you sub-patch an object, youare actually interpolating geometrybetween each point in your object Take alook at Figure 14-2, which shows twosub-patched objects

The object on the left is a simple boxwith a single cut running down the center.Moving the points at the center of this boxcreates a smooth arc from one end of theobject to the other This arc is caused by theinterpolation of geometry that occurs when

an object is sub-patched Now take a look atthe object on the right It is the same box,but in this case, there are six more cutsrunning through it Moving the middlepoints on this object still results in an inter-polation of geometry; however, since thepoints on either side of those being movedare now closer together, the arc is tighterand more pronounced Understanding this

293

Figure 14-2: Low poly count enables broader changes to your model.

simple truth is the key to effective subpatch

modeling The more polygons you have in a

given area, the more pronounced the effect

on the movement of points in that area

Take a look at Figure 14-3 Keeping in

mind what you saw in Figure 14-2, you can

imagine what would happen if you moved

the points on either of these objects

Undoubtedly, the object on the left would

enable you to make broad changes (similar

to the object on the left in Figure 14-2)

Small movements to the points on this

object would not have a drastic impact on

its overall shape That’s not true for the

object on the right Even minor

adjust-ments to this object’s points would result in

a noticeable change to its form

Learning to control the poly count and

understanding where and when it’s

appro-priate to add more geometry is a skill that

takes time to develop But suffice it to say

that as you model, you should strive to keep

your poly count as low as possible

Poly Flow

The other quality that makes a good headmodel is proper polygon flow Flow is a diffi-cult concept to grasp, especially for

beginners In essence, it is the deliberatelayout of polygons into overlapping bands orloops that, when fully realized, mimic thenatural flow of muscles under the skin.Keep in mind that as you model, you aresimulating reality Whether it’s a wineglass,

a sports car, or a human being, you arebuilding a simulation of a real-world object

In the case of organic models such as mals and people, you are simulating thefeatures that make up their outward appear-ance, typically muscle and bone It isimportant, then, to study in great detail theforms you are attempting to simulate.Amazing character models aren’t created byaccident The best character modelers arethose who have a solid grasp of humananatomy

ani-Figure 14-3

Figure 14-4: Basic muscle flow of the human head.

Figure 14-5: Bad polygon flow (left) compared with good flow (right).

Unfortunately, an introduction to anatomy is

beyond the scope of this chapter, but I

would encourage you to pick up an anatomy

book or attend a figure drawing class if you

intend to pursue character modeling And I

would strongly encourage you to visit

http://www.fineart.sk and http://www.3d.sk

These two sites offer the most

comprehen-sive set of resources for character modelers

that you can find

The need for ideal polygon flow doesn’t

stem from a purist compulsion Like

poly-gon count, it is a practical requirement

Consider this: Character models are rarely

built to hold a single pose or a solitary facial

expression (like Michelangelo’s sculpture of

David) On the contrary, they are built to be

animated and posed in a variety of fashions

A real face can make expressions (e.g.,

smiling or frowning) because of the layout

of muscles in the face Therefore, if your 3D

model’s polygons do not mimic the flow of

muscles in a real face, it will be difficult to create realistic expressions in a simulated

face You will find yourself fighting themodel to get so much as a smirk Itbecomes imperative, then, to build a modelwith great flow

In Chapter 10, we built a head modelusing the detail-out approach The advan-tage to the detail-out approach is that it is aWYSIWYG process You have immediatefeedback on the model at each stage ofdevelopment The problem with thedetail-out approach is that poly-by-poly con-struction makes it frustratingly difficult todevelop good flow (especially for beginners)and it often yields objects with a high polycount Spline modeling, however, avoidsthese pitfalls, allowing you to visualize theflow of your polygons and to selectivelyadjust the resolution of each patch for opti-mal poly count

Spline Modeling Pitfalls

Spline modeling, while elegant and efficient,

is not without its problems As we’ve seen

in previous chapters, there are rules that

need to be followed And even when the

rules are followed, the occasional “Curves

Do Not Cross” error will appear (seemingly

for no reason at all) Moreover, spline

mod-eling’s greatest strength can also be its

biggest weakness, especially when dealing

with organic models While splines make it

easy to visualize the flow of your polys, you

must have a solid understanding of flow in

the first place to build them correctly You

also have to be extremely careful when

specifying your Perpendicular and Parallelpatch settings to avoid creating polygonsthat do not line up properly from patch topatch And as if all of that weren’t enough,the cold hard truth is that some objects arenot well-suited for spline modeling Thesedrawbacks cause many modelers to steerclear of splines altogether But you’re inluck — I’m going to show you severaltricks to work around these peskyproblems

Spline Modeling Tips and Tricks

The major pitfalls of spline modeling can be

avoided by following these simple tips and

tricks

• Tip 1: Use splines for their strengths,

not their weaknesses It sounds obvious,

but you’d be surprised at how many people

don’t get this Splines work best as a

visual-ization tool, allowing you to establish the

overall form of your object quickly and

eas-ily They do not work well for creating

intricate details, but I see people attempting

this all the time They build spline cages

with an incredible amount of detail and

expect to simply patch it and be done It

sounds great in theory, but it rarely works

out in practice So rather than using splines

as a be-all and end-all, use them for what

they’re good for — namely building the

overall form of your object Then use the

other tools at your disposal to model in the

details

• Tip 2: Build quad cages It’s best to

build your cage so that every region is

bounded by four splines I call this a quad

cage It consists of splines for the top,

bot-tom, left, and right for each area in your

cage, both large and small Building a quad

cage is perhaps the most critical component

of spline modeling, and I’ll be teaching you

more about it as we proceed

• Tip 3: Use simple patches One of the

most time-consuming aspects of spline

modeling is determining the proper Parallel

and Perpendicular patch settings Figuring

this out is like some sort of twisted game

You have to remember which spline youselected first in order to establish how theperpendicular and parallel patches are con-structed And then you have to ensure thatthe patches line up properly to those aroundthem It’s a hassle, but here’s a simple solu-tion: Use the same patch settings for thewhole object If you construct your splinesproperly (by making sure your patchedareas are roughly the same size), you canuse the same patch settings for your wholeobject This can save you loads of time andfrustration down the line

Keep these simple tricks in your backpocket and they will make your spline mod-eling job much easier

Now that we’ve covered the basics,we’re ready to start modeling Here’s anoutline of what we’ll be doing:

1 First we’ll build the spline cage I’mgoing to show you how to construct acage with great flow using the tricksoutlined above Once built, this cagecan be saved and used over and overagain to quickly knock out other headmodels

2 Next, we’ll patch the splines, add a fewdetails, and learn how to reduce thenumber of polygons to obtain an opti-mal poly count

3 Lastly, we’ll construct the remainingdetails using tools you’re already famil-iar with

Fire up Modeler and let’s get started!

297

Creating the Cage

As was the case with the detail-out

approach, it’s helpful (and often necessary)

to use a reference image when building

your spline cage You can find the images

for this chapter on the companion CD under

Images\Chapter14 In the Setup\Chapter 14

folder, there is a Backdrop config file Bring

up the Display Options window (<d>) and

click on the Backdrop tab From the

Pre-sets pop-up menu, select Load Backdrop

and load the Spline_Head_Backdrop.cfg

file

Once your images are loaded, zoom in on

the eye on the right (which is the

charac-ter’s left eye) Oftentimes, finding the best

place to start a spline cage can be difficult I

chose the eye as a starting point because it

can easily be divided into four sections (top,bottom, left, and right), and that provides agood starting point for building a quad cage(see Tip #2 above)

1 Begin by laying down three points overthe top of the eye in the Back viewport.Then, with the points still selected, use

the Create | Curves | Make Curve

| Make Open Curve tool (or press

<Ctrl> + <p>) to generate your first

spline Finally, use the Drag tool (or asimilar tool for moving points) to adjustthe spline in the Right view Keep inmind that the eye bulges out in thecenter, so your middle point shouldstick out farther than the points oneither side

Figure 14-6: Load the Spline_Head_Backdrop file that we’ll use as a reference for

building the spline cage.

Don’t feel that you have to adhere to my

particular workflow I find that laying down

points and then converting them into splines

gives me the control that I want, but if

you’re more comfortable using the Sketch,

Bezier, or Spline Draw tools, go right ahead.

It’s not important how you arrive at the end

result so long as you are comfortable with

the process used to get there.

Note

The most basic curve consists of a starting

point, an ending point, and a control point

somewhere in between You can build your

splines with as many points as you like, but

keep in mind that the more points you have,

the more difficult it will be to adjust the

overall shape of the spline.

Note

As we build our splines, many of them will

jut up against each another, creating harsh

angles between them This is nothing to

worry about There’s no need to rebuild your

splines We’ll be fixing these harsh angles

after we’ve completely built our cage.

Note

You’ll notice as we proceed that the splines I lay down don’t strictly adhere to the refer-

ence image Remember Tip #1! At this

stage, we’re only interested in getting the basic form We’ll be doing plenty of fine-tuning to the model after we patch it.

So do yourself a favor: Don’t waste time ing to precisely match the reference image Focus on the overall form Getting it close is

try-good enough for now The actual refining

stage comes later.

Notice that this spline does not extend overthe top of the entire eye Rather, it coversabout 70 to 80% of the total area This isdone to ensure that the splines on eitherside of the eye are roughly the same size asthose on the top and bottom RememberTip #3 We want to create patches that areroughly the same size If they are signifi-cantly smaller, the polys created bypatching this area will get crammedtogether, resulting in an unpleasant pinch-ing effect that’s difficult to remove in thefinal object

299

Figure 14-7: Create the first spline over the top of the eye.

2 Create three more points in the Back

viewport along the bottom of the eye

and press <Ctrl> + <p> to convert

them into a spline Then shape the

spline in the Right viewport as you did

in Step 1 The middle point on thisspline should stick out farther than theendpoints but not as much as the mid-dle point for the top of the eye

Figure 14-8: Create the second spline along the bottom of the eye.

Figure 14-9: The third spline is created by using the two existing points from our

Shaping the spline in at least two of the

three viewports is something you will always

need to do From here on out, I’m going to

describe the creation of each spline, but I

will expect you to make the adjustments

necessary in each viewport.

3 Create a single point at the outside

cor-ner of the eye Then deselect it Now

select the outside point on the top

spline, followed by the point you just

created, and finally the outside point on

the bottom spline Press <Ctrl> +

<p> to create a new spline.

4 Create a single point at the inside

cor-ner of the eye Then deselect it We’re

going to repeat the procedure in Step 3

for the left (inside) part of the eye

Select the point on the inside top

spline, the point you just created, and

then the point on the inside bottomspline Then create a new spline by

Inspecting your splines like this is a habityou should get into Check it from multipleangles and don’t be afraid to move pointsthat seem out of place Oftentimes you’llfind that the Perspective view will revealproblems that would be difficult to identify

in the orthographic views alone

Now that we’ve got an initial outline, it’stime to branch out

5 Create three more points over the top

of the eyebrow and convert them into aspline

301

Figure 14-10: The fourth spline is created in the same manner as the third by

using two existing points and a third new point at the inside corner of the eye.

6 Create three points under the eye

(about the same distance below as the

eyebrow spline is above) Then convert

these into a spline The inside point for

this spline should rest at the base of

the nose and the outside point should

rest on the cheek bone

7 Add a new point where the top of thenose and the eyebrow meet Move itback slightly on the Z axis, then dese-lect it Select the inside point from theeyebrow spline, the point you just cre-ated, and the inside point from the

spline below the eye Press <Ctrl> +

Figure 14-11: Create a new spline over the eyebrow.