Essential LightWave 3D- P18 potx

Navigate to Scenes\Chap-ter_19 on the CD and load the Skirt scene.The object in this scene is a simple tube.The points at the center of the tube wereextended out to form the skirt and Ba

the object Click on the Save Motion

button and save the object’s motion to

a location on your hard drive

16 Once you’ve saved the motion file, you

gain the ability to adjust the speed of

the simulation Change Playback Speed

to 30% The animation will now play at

one-third of its regular speed In order

to see most of the effect, we need to

change our end frame

from 60 to 90 Once

you’ve done this,

cre-ate another preview

animation

The bricks now look great

at 30 frames per second,

but the ball no longer

moves with them That’s

because we’ve only

changed the playback rate

for the brick wall Let’s

adjust the timing of the ball

to match

17 The motion of the ball is controlled by

the Ball Hinge null object Select this

object from the Current Item pop-upmenu (just below the timeline) and

press <Ctrl> + <F2> to bring up

the Graph Editor Select the first

chan-nel on the left, then hold the <Shift>

key down and select the last channel sothat all of the channels in between are

selected Using your right mouse

but-ton, drag a bounding box around all of

the keys in the main Graph Editor

win-dow to select them Then, from the

Keys pop-up menu, select the

Numeric Scale option The Scale

Keys window will appear Change Time

Scale factor to 3 and press OK The

motion of the ball now matches up with

our brick wall

At this point, you can continue tweaking

with the animation to make it truly

excep-tional Try adding Colin Cohen’s Vibrate

plug-in (available on the CD) to the camera

for realistic camera shake as the ball

impacts the wall Play with the tools in the

EditFX tab to alter the motion path for

errant bricks (look closely and you’ll see

them) Allow this introduction to HardFX to

serve as a launching pad as you continue to

explore LightWave Dynamics

ClothFX

ClothFX is a personal dynamic that gives

your object elastic qualities You should

apply ClothFX to objects that you want to

deform naturally and organically For ple, ClothFX can be used to simulateclothing that stretches and folds over acharacter’s body But ClothFX isn’t just forclothing It can be used to leave footprints

exam-on the ground where a character walks Itcan be used on the surface of a pond to cre-ate ripples and waves It can even be used

to simulate the motion of hair ClothFX is

an extremely powerful tool that can yield animpressive array of results

In this section, I’ll show you how youcan use ClothFX to simulate clothing foryour characters Navigate to Scenes\Chap-ter_19 on the CD and load the Skirt scene.The object in this scene is a simple tube.The points at the center of the tube wereextended out to form the skirt and Band-Saw was used to slice it into smallersegments The points at the top and bottom

of the tube, along with those at the pointwhere the skirt connects to the tube, wereplaced into a selection set called Fixed.Finally, the skirt itself was converted into asub-patch object It may not look like much,but that’s the beauty of it ClothFX can turn

a ho-hum object such as this into something

great

Before we begin ing the settings forClothFX, let’s talk brieflyabout the scene The tubeobject already has threekeyframes, which give it aslight spin to its right Youshould make it a rule to set

tweak-up and refine your motions

first, then apply ClothFX

for the soft-body tion The order here isimportant If you set upyour dynamics first, thentweak the motion of your

simula-Figure 19-28: Our simulated Skirt object.

object, you will have to rework the

simula-tion all over again

Note

It’s important to understand that ClothFX is

not designed to be a “one sim for every

occasion” dynamic In other words, you

can-not assign it to your character’s clothes and

expect the same settings to work flawlessly

in every situation ClothFX is only a

simula-tor and its results will vary depending on

what you’re asking it to do.

You’ll notice that the tube is the only object

in the scene Technically speaking, this

vio-lates the principal law of the Dynamics

Community, as there are no opposing

dynamics to which this object is

account-able Under normal circumstances, we

would correct this by adding a social

dynamic such as Gravity But in this

situa-tion, we can avoid the extra trouble of

setting up an independent Gravity object

and simply use the Gravity setting available

in ClothFX

1 Bring up the Object Properties panel

for the Skirt Click on the Dynamics

tab and choose Cloth from the Add

Dynamic pop-up Then click on

ClothFX in the Dynamics list to bring

up its settings

NoteThere is a bug in LightWave (confirmed in versions up to 8.0.1) that causes ClothFX to calculate parameters improperly if they’re entered in the “wrong” order, but it will cal- culate them correctly if the scene is saved, reloaded, and calculated again Hopefully this bug will be fixed in the next revision of the software But for now, be aware that this problem exists If you change a setting and calculate, but are unhappy with the results and revert back to the original settings only

to find that the object no longer deforms like

it did before, you’re experiencing this bug Save your scene, clear Layout, and reload the scene to work around the problem.

Due to a bug in ClothFX, I cannot walk you

through the individual application of each

setting, but I can walk you through the

group application of specific settings And

again, keep in mind that these settings aredescribed in detail in the manual and onlinehelp system

2 In the Basic tab of the ClothFX

prop-erties, select the Fix pop-up menu and

choose the Fixed/

pointset option The

Fix option allows you tochoose the points thatwillnot be affected by

ClothFX All of thepoints in the object

except those in the skirt

were added to the Fixedselection set By choos-ing that selection sethere, we are tellingClothFX to ignore therest of the object andfocus solely on theskirt

500

Figure 19-29: The default ClothFX settings.

3 Change the Spring and Sub Structure

settings to 750 Spring deals with the

ability of a point to move closer to or

farther away from those directly in line

with it Sub Structure deals with the

ability of a point to move closer to or

farther from those directly across from

it (See Figure 19-31.) Increasing these

settings makes it more difficult for the

points of our object to move from their

original positions and will help simulate

a more sturdy cloth like cotton rather

than a more flimsy one like silk

NoteThe settings used to get the “right” look for each Dynamic object are greatly dependent upon the size, shape, and number of poly- gons in the object The settings we’re using

in this tutorial will work well for this object, but they may not work for a different object It’s important, then, to pay close attention to what each setting does Learning the role of each setting will help you troubleshoot prob- lems in the simulation and enable you to make intelligent decisions about what changes need to be made when those prob- lems arise.

4 With Spring and Sub Structure set,switch to the Etc tab and change Grav-

ity to –9.8 m Changing gravity here

eliminates our need for an independentsocial dynamic in our DynamicsCommunity

5 Press Calculate and take a look at the

results

Figure 19-30: Change the Spring and Sub Structure settings to 750.

Figure 19-31: Spring and Sub Structure as they

affect quad polygons.

6 The object now has a sense of weight

(having activated Gravity) and is

begin-ning to look more like cloth; however,

it’s colliding with the tube object Let’s

fix this Switch to the Collision tab and

set Collision Detect to <all> This

opens up a variety of options We can

leave most of these at their default, but

change Collision

Off-set to 30 mm.

Adjusting the offset

helps keep the skirt

from penetrating the

surface of the tube by

creating a 30 mm

invisible barrier

between the two

Finally, set Self

Colli-sion and Double Side

to <all> This will

ensure that the skirt

can interact with

itself

7 Press Calculate and

check the results

again

502

Figure 19-32: Set Gravity to –9.8 m.

Figure 19-33: Adding Collision detection helps keep the skirt from passing through itself and other objects.

Adding collision detection certainly helped,but it didn’t completely solve the problem

We can increase Collision Offset to sate, but there’s a larger issue here Theskirt is stretching in ways that pull the poly-

compen-gons into the tube We need to resolve the

stretching

8 Click on the Advance tab Increase

Compress Stretch to 15000% and

reduce Stretch Limit to 0.25%

Com-press Stretch limits an object’s ability

to stretch How far it is allowed to

stretch is determined by Stretch Limit

9 Press Calculate and check the results.

These changes helped constrain the skirt

and are keeping it from

penetrating the tube

sur-face, but the cloth now

looks like it’s suffering

from a bad case of static

cling There are several

reasons for this One is

that the cloth is too

heavy When it swings

around, it hits itself and

gets caught in its own

self-collision routines

Another is that the cloth

is a little too responsive

to the object’s motion

We could increase the

Spring and Sub Structure

settings to make it stiffer,

but there’s another setting we can use toresolve this

10 Switch back to the Basic tab Decrease Weight to 0.1 This will make the cloth

lighter and a little less responsive tothe skirt object’s motion Then

increase Viscosity to 3 Viscosity

oper-ates as a dampening effect, making the

Figure 19-34: Boost Compress Stretch and reduce Stretch Limit.

Figure 19-35: Change the Weight, Viscosity, and Resistance settings.

motion of the cloth less severe Finally

change the Resistance setting to 0.5.

This will make the cloth less resistant

to wind and help its overall motion

11 Press Calculate and check the results.

Making these last few changes really

helped, and our skirt is now looking much

better But it seems to be puffing out at the

point where it connects to the tube object

To fix this, we can tell the Sub Structure

setting to only pay attention to the Skirt

surface

12 From the Fx pop-up menu to the left of

Sub Structure, select the

Skirt/sur-face option Calculate and check your

results

That did it! We now have a great-looking

skirt that responds well to the motion

we’ve set up in our animation ClothFX is

an incredible tool and can produce amazing

results From here, you should continue to

experiment and play with the settings The

more you work with ClothFX and become

familiar with it, the more it will reward youwith outstanding results that would beimpossible to create by hand

504

Figure 19-36: Limiting the Sub Structure to just the skirt gives us just the

look we want.

In this final section, we’ll be looking at

several of the options available in SoftFX

1 Bring up Layout and load the

Bendy.lwo object from the Objects\

Chapter 19 directory The Bendy object

is a simple tube that was sectioned off

with BandSaw It was then converted

into a sub-patch object It has two

weight maps One is a gradient from

0% at the bottom to 100% at the top

The other is localized to the blue

sur-face around the tube’s blue center

2 Let’s set a few keyframes to give this

object some motion At frame 10, move

Bendy –200 mm to the left At frame

20, move him 200 mm to the right.

And at frame 30, move him back to 0.

3 Play back the animation and take note

of the motion

4 Now bring up the Object Properties

panel and from the Dynamics tab, add

SoftFX from the Add Dynamic pop-up

menu There are a number of options

here, but before we change any of

them, click Calculate to see what the

default settings do to our object.You can see that the original motion hasbeen exaggerated and the object appears to

be bound by a large rubber band Evenwhen the object reaches the final keyframe,

it continues to move back and forth, itsmotion dampening over time

As a personal dynamic, SoftFX is subject

to the laws of the Dynamics Community.And in the Dynamics Community, everypersonal dynamic must be accountable to asocial dynamic However at this point, weonly have one personal dynamic in ourscene There are no social dynamics Only abit of motion Ah, but there it is You see,

motion is a social dynamic It’s a

user-defined social dynamic that every personaldynamic will respond to SoftFX stillresponds to collisions, gravity, and wind, butit’s uniquely designed to respond to motion.Let’s take a look at the SoftFX options

Figure 19-37: Set your keyframes, then calculate SoftFX with the default

settings.

5 Click on the Input tab of the SoftFX

properties Change the Motion Force

setting to 500% and recalculate.

6 You can see that the object is now

much more responsive to its motion

Return Motion Force to 100% and click on the Operator tab The Opera-

tor tab fine-tunes the effect of motion(or optionally wind) on the object.There are two Operator maps At thispoint, the top one is set to <all>,meaning that the motion will affect theentire object

7 The wave graphic to the left is a visualindicator of the falloff that will beapplied to your object’s motion Change

the EffectSize to 0% and recalculate.

The residual motion has been severelyreduced and it now looks as if SoftFXhas not been applied The EffectSizesetting works hand in hand with theMotion Force setting to determine theextent of the object’s reaction tomotion Change EffectSize back to

100% and change WaveCycle to 1.

Calculate and check the results Thenumber of times the object moves after

it reaches its final keyframe has beenreduced Change WaveSize(s) from 0.5

to 3 and calculate again to see the

results The time it takes to completethe motion after the object reaches itsfinal keyframe has been extended

8 This motion isn’t very realistic so let’schange the settings to something more

“natural.” Keep EffectSize at 100% and change WaveCycle to 5 This will

create more motion after the lastkeyframe has been reached Change

WaveSize(s) to 0.1 This will shorten

the time needed to complete the

resid-ual motion Press Calculate and check

the results

The object now appears to have come to ahard stop As you can see, the Operator set-tings greatly affect your object’s response

to motion Up to this point, we’ve onlyaffected our object’s position in response to

506

Figure 19-39: The Operator tab allows you to

fine-tune the effects of motion on your object.

Figure 19-38: Change Motion Force to 500%.

its motion However, by using an influence

map (such as a weight map, selection set, or

even a surface), we can alter our object’s

shape as well

9 Click on the Operator1 Map pop-up

menu and choose the Influence/

weightmap option The Influence

weight map (described at the beginning

of this section) is a graduated weightmap with 0% influence at the bottomand 100% at the top Leave EffectSize

at 100%, but change WaveCycle to 3 and WaveSize(s) to 0.3 Then calculate

to see the results

10 You can see that the object sways backand forth as if made of rubber But ifyou look closely, the deformation iscompletely linear and the objectappears to slant, giving it a slightlyunnatural quality What if we want thedeformation to be a little more natural?

We can affect the application of thedeformation by applying a mode Fromthe Mode pop-up menu, choose

Square and recalculate.

Square does not refer to the shape of themotion (as in square, rectangle, or triangle).Rather, it describes the application of thedeformation Square here is a mathematicalterm, as in E=mc² It amplifies the defor-mation of our object by multiplying the

Figure 19-41: Assigning an Operator map allows us to deform our object

based on its motion.

Figure 19-40: Creating a “hard stop” type of

motion.

Weight percentage by itself This causes

the top to receive significantly more

defor-mation than the bottom You can change the

Mode setting and get immediate feedback

on the results without having to recalculate

Feel free to try out the different modes to

see how they affect the model When you’re

finished, set Mode back to Square.

11 The deformation of our object now

looks good Let’s make one last

adjust-ment to this animation Click on the

Bump tab The Wave settings at the

bottom half of this tab allow you to

define cyclical deformation When

restricted by an influence map, it opens

the door for a variety of effects We’ll

use it to make our Bendy object

breathe

12 Change the Make Wave By option to

<all> This applies the Wave

deforma-tion to the entire object We can then

use the Fx pop-up menu to specify the

strength of the deformation Choose

the Chest/weightmap option The

Chest weight map is localized to theblue section (or chest) of the Bendyobject The wave effect will have astrength of 0 outside that area and willgradually increase toward the center of

the chest Change WaveSize(s) to 0.01.

This affects the size of the deformation.You can leave LoopCycle at its default

of 5 LoopCycle determines the

num-ber of wave deformations, but sincewe’ve restricted the deformation by aweight map, this setting does not applyhere You can also leave LoopSpeed at

its default of 2 LoopSpeed determines

the speed of the deformation Thedefault of 2 will produce a “rapidbreathing” effect on this model Youcan reduce this setting for a more natu-ral motion or increase it for hyperventi-

lation Press Calculate and check out

the results

508

Figure 19-42: The modes affect how the deformation is applied.

Our Bendy object now responds frenetically

to his motion and breathes hard from the

rapid pace It’s worth noting that the

set-tings for WaveSpeed and WaveSize can be

keyframed with an envelope by pressing

the E button This will enable you toincrease or decrease these effects overtime, causing the breathing to start slowand pick up after the basic motion iscomplete

.

As usual, we’ve covered a lot of ground in

this chapter, but in reality, we’ve only

scratched the surface Dynamics are

incred-ibly powerful tools They are also a lot of

fun to work with Now that you’ve been

introduced to the characters in the ics Community, I encourage you to spendtime becoming well acquainted with them.It’s a relationship that will reward yougreatly for the investment

Dynam-Figure 19-43: Automated breathing, complements of SoftFX.

Simulations 3:

Fur and Hair

In this chapter, we’ll take a detailed look at

the tools needed to simulate hair and fur

through the use of LightWave’s SasLite

plug-in SasLite is the younger brother to

Sasquatch, a comprehensive hair and fur

simulator developed by Worley Labs The

focus of this chapter will be on the

capabili-ties of SasLite, but we will also examine the

differences between it and the full version

of this amazing utility

An Introduction to SasLite

SasLite is a wonderful tool that allows you

to add fur and hair to your objects It works

as both a displacement plug-in and a pixel

filter As such, you need to enable it in two

different places in LightWave in order to

see the effect

Let’s jump right in and see how it works

1 Make a 1 meter sphere in Modeler, and

bring it into Layout (or simply load

objects\Chapter20\1MeterBall.lwo

from the CD)

2 Open the Object Properties panel by

tapping <p>, and click on the Deform

tab, where the displacement plug-ins

are stored Click on Add

Displace-ment, and choose SasLite from the

list (See Figure 20-1.)

3 Double-click on SasLite to open the

Sasquatch Lite options panel For now,

just change Fiber Color to something

you like, and leave everything else atthe default values (See Figure 20-2.)

4 Tap <Ctrl> + <F8> (or go to

Win-dow | Image Processing…) and

open the Processing tab of the Effectswindow You’ll see places to add twokinds of filters to your rendered image:pixel filters and image filters SinceSasLite is a pixel filter, that’s the one

you want Click on Add Pixel Filter and choose SasLite from the list (See

Figure 20-3.)

510

NoteRobin Wood is the artist who wrote the doc- umentation on SasLite for the LightWave [8] manual She is an expert on SasLite and has been kind enough to share her knowledge with us by authoring this chapter.

Note

I won’t be going into great detail about what each of the SasLite options does, because I’ve already covered that in the LightWave 8 documentation If you don’t yet have LightWave 8, you can find that portion

of the documentation on the companion CD

in the Sas Settings folder.

Figure 20-1: SasLite in the Add Displacement menu.

Figure 20-2: The Sasquatch Lite panel.

5 Double-click on the filter name to open

its options Click Self Shadowing to

enable it, and close the panel by

click-ing OK.

6 Tap <F9> to render a single frame.

Congratulations! You’ve used SasLite

and made your first fur ball!

7 But we’re not going to stop here,because I want to show you something

else Tap <L>, then <p> (or click on

Lights and then Properties) to open

the Light Properties panel Change

512

Figure 20-3: SasLite in the Add Pixel Filter list.

Figure 20-4: Enable Self Shadowing in the

Sasquatch Lite panel.

Figure 20-5: A lovely fur ball!