Essential LightWave 3D- P16 pot

When you first load ShadowCatch_Raw.lwo, it has a default surface on it, with its Trans-parency bumped up to 80%, so it will receive shadows and still show the back-ground image throug

• Random Streaks are

the fine, numerous “spiky

streaks” that help give the

impression of something

being painfully bright

• The Reflections tab

offers access to a multitude

of settings to recreate the

sun dogs that appear when

light catches within the

mul-tiple layers of camera optics

(I’d suggest using this

set-ting sparingly, creaset-ting your

own custom combinations of

elements instead so this effect doesn’t look

canned.)

Let’s go back to the fake volumetric light

scene we were working on in the previous

section of this chapter, as shown in Figure

17-29

1 Set the light’s Parent to your “shaft of

light” object, and move it numerically

to X=0, Y=0, Z=0 (I’ve changed my

light from a distant light to a point light,

but this doesn’t really matter.)

2 Activate Lens Flare for the light, and

open the Lens Flare Options window

Deactivate Central Ring and Red Outer

Glow Activate Anamorphic

Distor-tion and Anamorphic Streaks.

(Leave everything else as is.)

3 An <F9> gives you something you

might see hovering over a rural

land-scape on The X-Files (See Figure

17-29.)

One of the best ways to use lens flares is to

work them into your scene in such a way

that the viewer isn’t even aware that a lens

flare is being used (Huh?) That’s right!

When you have a flare that is just a Central

Glow with a high Intensity and a fairly high

Flare Dissolve, the flare serves more to add

a bit of “light bloom” to the entire scene,giving the same feel that lights do when

“catching” in a faint hint of haze This fainthinting is indicative of the elusive quality ofsubtlety that runs through all I try to con-vey to an up-and-coming artist Anyone cantell the difference when shown a render

“with” and a render “without,” but on itsown, it doesn’t jump out at the viewerbecause it just looks good

Figure 17-27: Random Streaks.

Figure 17-28: The Reflections tab.

Lens flares aren’t just for “realistic” works.

The addition of two lens flares in the center

of the work in Figure 17-30 makes the

ver-sion on the right much more intense, all

over! I had to use two flares because I

wanted a soft, “all-over” glow and another,

much more pinpoint focus for the sciousness seed” at the center of the work.Flares render very quickly, so don’t beafraid to use as many flares as it takes to getthe exact look you’re trying to create

“con-Figure 17-29

Figure 17-30: The Formation of Consciousness.

LightWave lets you composite CG elements

right into live-action plates without having

to open up another piece of software It’s

quick, it’s easy, and it opens up a whole newworld of possibilities to a filmmaker Let’stake a look at an example

CG Elements onto a “Live-Action Plate”

1 Load iting_01_Setup.lws — the layout of

Scenes\Chapter_17\Compos-the three ’droids — and we’re ready togo!

Figure 17-31: A deserted country road — the

perfect place for a trio of alien probe ’droids!

(Insert maniacal laughter here.)

Figure 17-32

2 The first step to getting these guys

composited onto a live-action plate is to

load that plate into Effects |

Compos-iting | Background Image (Either

select the plate, if CountryRoad.png

is already in the list, or choose (load

image) and select

Images\Chap-ter17\CountryRoad.PNG if it isn’t

in the list.) You can get a really goodfeel for how this composite will look by

choosing Background Image in the

Display Options | Camera View ground — your camera viewports willshow your objects over your back-ground image

Back-Figure 17-33

Note

The ’droids use the FI’s_PatchyR procedural

texture.

PC crowd: You’ll have to make sure you add

the fisptxtrs.p plug-in (More info on FI’s

pro-cedural textures can be found in Appendix A.)

Mac crowd: Using Surface Baker (see the

LW manual for more information on this très

cool shader that is currently hard-coded as a

part of LightWave — it can’t be used over

ScreamerNet just yet), I’ve created a Mac

version of the probe ’droid for these next

exer-cises Be sure to work with the _Mac versions

of the ’droid and his scenes.

If you’re wondering how to “bake” a

procedural bump channel when Surface Baker doesn’t have this as one of its options, see the

LW manual to get up to speed on the “whos” and “whats” of Surface Baker You copy the texture layer(s) you’re using for the bump channel to replace all layers of your color channel and with 100% Luminosity, 100% Dif- fuse, 0% Specular, 0% Transparency, and 0% Bump, render a frame with the Surface Baker shader active and set to create an appropriate

UV texture map The image the Surface Baker shader generates can be used as a bump map for machines that don’t have access to your procedural shaders!

3 Let’s change our light to an area light

so it will cast realistic shadows In its

Motion Options window, set Target

Item to ProbeDroid (1) (the middle

’droid in our scene), so when we move

our light, we don’t have to worry about

aiming it as well Move it to where the

sun would be relative to our ’droids,

based on what we’re able to surmise

from our live-action plate (I found X=1.63,Y=15.88, Z=–240 mm to work well) Set

Light Intensity to 125% (I always have a

value of over 100% for sunlight; it givesharsher lights and darks — chiaroscuro —

and feels more like outdoor lighting.) Make

sure Shadow Type is set to Ray Trace, activate Trace Shadows under Rendering Options, and do an <F9>.

Figure 17-34: Doing an <F9> shows us what

we’ve got so far It’s not bad and could probably

pass as okay in some lower-end productions But

something is amiss: The lighting on the ’droids is

coming from a completely different angle than

where the sun obviously is in our plate!

Figure 17-35

Note

One of the first things you learn as a painter

is that no matter how many visible or implied

lights there are in an image, there is only one primary light source Unless you have a

darn good reason for breaking this tion, all things in a scene should show the

conven-effect of the primary light source; all other

light sources should be handled with such subtlety that they go almost unnoticed to the untrained observer (When in doubt about complex lighting, or when you have a lim-

ited time to ray-trace, shadows are cast only

from the primary light source.) These conventions have worked for hun- dreds of years But even so, you still don’t have to take it as “law,” just as an idea to

help make your own work better, faster!

4 Under Effects | Backdrop, choose

Image World from the Add

Environ-ment pop-up menu, and then choose

our backdrop image,

Country-Road.PNG, in the Light Probe Image

box Then, on the Global Illumination

panel, select Enable Radiosity, select

Backdrop Only as the radiosity type,

and activate Shading Noise

Reduc-tion Change Intensity to 169%, and

do an <F9> to see what we’ve got.

What’s the big thing that stands out asbeing “wrong” when you look at Figure

17-38? The ’droids aren’t casting any

shad-ows! Compositing shadows onto things

seen in photographic plates is a bit of amulti-part process with the tools that are apart of LightWave’s basic toolset (Otherplug-ins exist that streamline shadow

Figure 17-36: Hmm… Well, the light is coming

from the correct direction, but the scene is dark.

We could spend a lot of time “hanging” other

lights to mimic the light reflecting off the ground,

pavement, sky, and all that, or we could use our

live-action plate to light our scene!

Figure 17-37

Figure 17-38: Hey! Not bad! Not bad at all! As a matter of fact, pretty darn passable! But something I’d like to see is to have the lens flare effect in the live-action plate carry onto our ’droids just a touch.

5 As shown in Figure 17-39,add a point light, naming it

Flare Set its Position to X=890 mm, Y=7.269 m, Z=–69 mm Set Light Intensity to 0%, and activate Lens Flare Set Flare Intensity to 200%, deacti- vate Fade Off Screen, set Flare Dissolve to 69%, and set it so that only Central Glow is active Set Star Fil- ter to 4 Point and the star

filter’s Rotation Angle to

45º (You can do an <F9> if

you like; I’ve already tested it andknow the effect is what I’m looking for,

but it is so subtle as to not really merit a

figure of its own.)

compositing — most notably Worley Labs’

G2, which does many other things for your

rendering as well, including letting you see

changes to your render in real time.)

But here, we’re going to show you how

to composite shadows using the basics of

LightWave right out of the box, without

having to own a separate compositing gram or buy additional software oranything!

pro-First, we’ve got to have something that

“catches” the shadows cast by the ’droids.This “shadow-catcher” is just a simple bit

of geometry that mimics the general shape

Figure 17-39

Figure 17-40

and position of the things seen in your

plate (You’d be surprised at how general

this “shadow-catcher” can be and still look

good.)

6 Load in

Objects\Chapter17\Shadow-Catch_Raw.lwo This object has been

presized and positioned to simulate the

curvature of the road where the ’droids

may cast their shadows Under its

Object Properties | Lights tab,

check to exclude Radiosity, Caustics,

and the light named Flare from being

calculated for that object; it’ll save lots

of time when rendering (The only light

that needs to interact with our

shadow-catcher is our primary light:

Light You may find it easier to match

your shadow-catching objects to their

respective landmarks on the plate

when they’re viewed as wireframes

and not as opaque, solid objects This

can be set through the Scene Editor.)

When you first load ShadowCatch_Raw.lwo,

it has a default surface on it, with its

Trans-parency bumped up to 80%, so it will

receive shadows and still show the

back-ground image through it This lets me tune the positioning of both the shadow-catcher and the objects that are casting theshadows When everything is as it should

fine-be (and everything should fine-be fine in ourscene with our prepositioned objects),move on to the next step where we’ll geteverything ready for a final render

Figure 17-41

Figure 17-42

7 As shown in Figure 17-42, set the

ShadowCatch surface Color to 0, 0, 0

(black) and its Transparency to 0% On

the Advanced tab, set the Alpha

Chan-nel to Shadow Density (which is what

will let us composite the black of the

object’s surface color onto our plate)

As final preparation for generating an

image that can be composited onto the

plate, we need a completely black

back-ground (“Premultiplying” our

fore-ground image with black helps the

computer deal with the rather touchy

process of seamlessly blending the

edges of our foreground image into that

of our background.) Replace your

Effects | Compositing |

Back-ground Image with

Images\Black-Square.iff.

8 Figure 17-43 shows our completed

foreground plate, ready for compositing

onto our background plate To work

with a single frame, as we are here,

once you have hit <F9>, under the

Render Display’s File menu, choose

Save RGBA | LW_PNG32 (.png).

Portable Network Graphics files are

the most compact file type that holds

both the image channel (24 bits) and itsalpha channel (another 8 bits), making

a total of 32 bits per channel in a single

file If you wanted to save a series of frames, perhaps if you were doing this

for a movie, you would set Save RGB

to a 32-bit file format under RenderingOptions (and possibly even save outthe alpha separately, just in case yourcompositing application needs the alpha

as a separate file)

Looking at Figure 17-43, you may be dering where the shadows are They’rethere, but they’re 0, 0, 0 (black), the same

won-Figure 17-43: The completed foreground plate, ready for compositing onto our

background plate.

Figure 17-44: The alpha channel for our plate.

color as our background image When we

take a look at our alpha channel, which is

what is used to “cut out” our foreground

elements, we see that the shadows are

there — but they’re white! (See Figure

17-44.) In a LightWave alpha channel, what

is white is opaque and what is black is

trans-parent (some programs have this reversed).

So, the white shadows on the alpha channelwill make the black of the foregroundplate’s image channel opaque where theshadows are!

9 Now, to piece the background and ground together, save your scene, andthen clear your scene (or start anotherprocess of LightWave), so we can have

fore-a completely “virgin” spfore-ace in which towork our “magic.” In that empty

scene’s Image Editor, load Images\ Chapter17\CountryRoad.PNG Also,

load the render of the foreground

ele-ments that you saved in Figure 17-43

(you can use mine, if you wish: ders\Chapter17\CompRaw_F.png).

Ren-With your foreground “plate” selected,

choose Clone | Instance to create a

“referential copy” of the image (SeeFigure 17-45.)

10 Then, with the instance selected,

choose Alpha Only for Alpha Channel.

(This “splits” the 32-bit image into one

Figure 17-45

Figure 17-46

image that has the colors of the

fore-ground elements and another image

that has their alpha “mask.”) Then,

under Effects | Compositing, choose

CountryRoad.PNG for Background

Image, choose your (original)

fore-ground image for Forefore-ground Image,

and choose your instanced image that

has been set to Alpha Only for

Fore-ground Alpha

Note

It’s times like this, when you’re compositing your render onto something shot on film, that you’ll want to render your foreground elements with the camera’s “filmic” soft fil- ter You may also want to add some “film grain” to the foreground elements using either the Wave Filter or Virtual Darkroom image filters (found under Effects | Pro- cessing | Add Image Filter).

Virtual Darkroom is an amazing piece of software It does much more than add film

grain It actually simulates the ways that

cer-tain films, processing techniques, and photographic papers would record the image that LightWave renders I’ve found that because Virtual Darkroom offers such a plethora of presets, it’s best to use this filter

on a prerendered series of frames (saved using an image format like Flexible Format, Radiance, SGI 64-bit RGBA, SGI 48-bit GRB,

or Cineon formats that support LightWave’s ability to create images in IEEE floating-point accuracy, higher-than-film-color-depth qual- ity, rather than in 24-bits-per-channel, television-color-depth images).

Virtual Darkroom can even be used (to a degree) to “color grade” your footage, giv-

ing it the unearthly feeling of Minority Report

or the look of footage shot in rural America

in the ’70s (the Kodak Gold 100 preset gives this look quite nicely) It even has settings for black-and-white film, letting you make your work look like it was unearthed from some esoteric, archive film vault.

Figure 17-47: It takes but a moment to render the

pieces together When you do, you’ll see the probe

’droids hovering over and casting shadows onto a

deserted country road, a freak incident that a

hapless traveler managed to catch on film!

Figure 17-48: Summer Vacation (undisclosed location), 1953.

Basic Explosions

What do you do if you want to make things

go “boom”? There are just as many ways of

doing this as there are ways of doing

any-thing else in 3D The “trick” of mapping an

image sequence of an explosion onto a

poly-gon that sits between the object that goes

“boom” and the camera is ancient (in

com-puter terms at least) But, ancient though it

may be, it still works beautifully and is used

today in productions big and small

The first thing we need when

compositing an explosion this way is an

image sequence of an explosion The very

best explosions are the ones that are

actu-ally filmed with the camera going faster

than its usual 24 FPS to give the

impres-sion that what you’ve got is a gigantic

fireball, not a smallish “pop.”

Seriously Important Note

Filming (or “taping” — see the following

note) explosions requires a lot of experience,

expertise, and training! No matter how

much of a “fire nut” you may fancy yourself,

don’t shoot your own explosions until you can

get someone who honestly knows what

they’re doing to train you properly!

Note

Filming refers to when you’re shooting on

film; taping refers to when you’re shooting

on videotape As nitpicky as this may seem,

using these terms correctly shows other

industry folks that you know what you’re

talking about Besides, it’s always best to

mean what you say, and to say what you

But remember, as with lens flares, popular and/or easy often means that your viewers

will be able to identify the umpteen ent places they’ve seen that particularexplosion (A solution to this is to use sev-eral explosion polys in front of one another

differ-to make something that looks slightly ferent from the stock footage.)

dif-However, with LightWave, you can make asimple explosion in a matter of minutes.(You don’t believe me? Just take a peekthrough the first bit of the next chapter —the explosion we’ll be using is the result ofthe HyperVoxel explosion exercise It’s notthe best explosion in the world, but forsomething that can be done, start to finish,

in about ten minutes, it’s decent enough.)

Figure 17-49

The one thing to really watch for when

choosing (and making) an explosion to put

onto a polygon is that the explosion doesn’t

touch the edges of its frame (How cool

would it be to have a beautiful “Death

Star-like” explosion with a hard line cutting

it off where the filmed explosion hit the edge

of its frame?)

The next thing we need to composite an

explosion is a scene in which to put our

“blazing blossom.” I’ve taken the liberty of

putting our little probe ’droid adrift in

space, with just enough resources to trigger

its self-destruct mechanism (Hey,

filmmaking is a dirty job; get used to it.)

1 Load

Scenes\Chapter_17\Compos-iting_02_Setup.lws, and you’ll see

something like what is shown in Figure

17-50

MacNote

If you’re a Mac user, remember to load in

the Mac version of the scene

2 Next, load plosionPoly_Raw.lwo Open the

Objects\Chapter17\Ex-object’s Object Properties window, and

deactivate Self Shadow, Cast Shadow, and Receive Shadow (it’s a

rare thing for a ball of fire to either cast

or receive shadows)

3 Then, using the Scene Editor, set the

explosion poly to be viewed as a

Wireframe or Bounding Box This

Figure 17-50

Figure 17-51

will help you considerably when you’re

positioning and scaling it, centering it

directly in front of the derelict ’droid

An <F9> reveals that I’ve left all the

wonderful work of applying the

explo-sion for you (Hey! How else are you

gonna learn?)

4 Next, enter the Image Editor, and load

the first image in the Images\HV_

Explosion sequence Then, set Image

Type to Sequence (Most explosion

sequences you’ll buy will come with analpha channel so you can “cut” theexplosion onto a transparent poly I’mnot a big fan of this because it leavesthe explosion looking flat So, set Alpha

Channel to Disabled.) Instead of the

explosion sequence starting right atframe 0, I want the audience to havesome time to register what’s going on

Figure 17-52

Figure 17-53

in the scene, so set Start Frame to 34.

(This just pushes the whole thing

ahead to start at frame 34 Don’t mess

with the In or Out points; they will

“trim” (shorten) the footage.)

Note

In the Image Editor, you can use the slider

directly below the image window to scrub

through the frames of an image sequence.

Or you can check Use Layout Time to link

the image displayed in the window to your

scene’s current frame.

5 In the Surface Editor for the explosion

poly, enter the Texture Editor for its

Color channel For the Layer Type,

choose Image Map Set Projection to

Planar, Image to the

HV_Explo-sion_(sequence) we just loaded, and

Texture Axis to Z Click on the

Auto-matic Sizing button to have

LightWave calculate the correct scale

and position for the image to perfectly

fill the poly Close the Texture Editor

window

6 In the Surface Editor’s Advanced tab,

set the Additive Transparency for the

surface to 100% This means that it

will add the value of whatever its

sur-face is to whatever is behind it If the

surface is black, then 0, 0, 0 gets added

to the pixels behind it (meaning there

is no change) If the surface is white at

a certain point, then 255, 255, 255 gets

added to the pixels behind it (and

think-ing in terms of 255, 255, 255 bethink-ing the

highest values a pixel can have, white

is the highest value a pixel can have; in

short, it’s like having a layer set to

Screen in Photoshop) The end result

of this is that the black background ofthe explosion will be completely trans-parent, and the lighter the explosiongets, the more opaque it’ll be

Figure 17-54

Figure 17-55: Doing a quick <F9> (around frame 50) shows something that doesn’t look half-bad But an explosion is light, not just color Let’s add a lens flare to simulate a lot of light flooding our camera’s exposure chamber and to give us something to hide our removal of the ’droid.