LightWave 3D [8] 1001 Tips & Tricks phần 6 pot

Versions: 6.5-8 668 Dave Jerrard | General Tips | All Levels More on Shading Noise Reduction Shading Noise Reduction can also be used to subtly soften ray-traced ows cast by distant, spo

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659 Policarpo | General Tips | Beginner

Train Your Eye

It helps to train one’s eye by studying paintings by the great masters likeCaravaggio, Vermeer, Rembrandt, and others Any book on art history will pro-vide you with ample examples of how painters have learned to depict reality viathe play of light and shadow This is another good reason to use the GoogleImage Search function to build up your library of reference material When youfind an image that inspires you, go about recreating it in 3D so that you come to

a better understanding of what it takes to achieve a particular look

Versions: 6-8

661 Lee Stranahan | General Tips | All Levels

Turn Ambient to Zero; Except When Radiosity Is On

It’s a pretty common hint to turn ambient intensity down I say turn it tozero, period Why? Because it’s evil, that’s why It’s nondirectional, additivelight — that means it makes all your objects slightly brighter This is useless It’slike a brightness control, and it adjusts your black point higher As I said — evil

If you want ambient light, toss in a distant light at a low level

Except … when radiosity is turned on, ambient intensity becomes a differentthing Now, it adjusts the level of radiosity bounce and it’s a good thing, indeed

In fact, it’s often useful to crank it up to 20, 40, 60% — levels nobody in theirright mind would use with regular ambient light

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663 Eki Halkka | General Tips | Intermediate

Recreating the Sun

Even though the sun is a huge luminous gas ball, it’s also very far away and

it only covers a small portion of the sky So it can be considered a small lightsource in relation to your scene As the sun is extremely far away, it also has aunique property not often seen in other, worldly light sources: Light rays comingfrom the sun are, in practice, parallel Shadows cast by the sun grow very littleover distance

LightWave’s distant light mimics these properties It can be thought of as aninfinitely small light source, infinitely far away For many scenes, this is a goodenough approximation for a sun

But if you wish to take your render a step further, you should take intoaccount the fact that the sun is not a pinpoint light source A distant light’s shad-ows are always hard Even though the sun’s shadows don’t grow much bigger

over distance, they do get a bit softer The soft edges, called penumbra, appear

where the shadow-casting object blocks the light source, the sun, only partially.You can try using a shadow-mapped spotlight, shining from very far away Thiswill give you softer shadows, but their softness is constant regardless of the dis-tance from the shadow-casting object

There are a few ways to do more realistic shadows Maybe the most accurateway is to use an area light, moved very far away and scaled so that its size isapproximately the same as the real sun’s perceived size, relative to the scene.Another way is to use multiple distant lights, each with their rotation slightlyoffset from each other and casting their shadows in slightly different directions.When you have enough of these lights, their shadows will blend together intoone soft-looking shadow You can use the spinning light trick to multiply theapparent number of these lights by the number of antialiasing passes, or evencreate the same result with a single distant light

Versions: 6-8

664 Policarpo, Eki Halkka | General Tips | Intermediate

Spinning Light Trick

Use the spinning light trick to simulate GI To get smoother shadows, justuse a higher AA setting

LightWave calculates motion blur by rendering a different time step at eachantialiasing pass and combining these to a single image If the Antialiasing set-ting is low and there’s fast motion in the frame, a series of ghost images can beseen The spinning light trick uses this phenomena to multiply the apparentnumber of lights in the scene When a high enough Antialiasing setting is used,the shadows from the lights blend together, giving the appearance of a singlesoft shadow

With a basic spinning light setup, the goal is to make the light rotate a fullrevolution, 360º, during the antialiasing passes LightWave’s default motion blurlength is 50%, so to get 360º of rotation, the light has to turn 720º each frame.One way to create spinning light rigs is by using Overcaster from Eki’s PlugPak

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When the user runs an Overcaster script, the script first reads some parametersfrom the scene The most important is the motion blur length of the current cam-era If the user has set the motion blur to, for example, 5%, the amount ofspinning must be increased to 7200º to get a full revolution during the

antialiasing passes, as the desired 360º is 5% of 7200

With high antialiasing and normal motion blur, a single spinning light willshine from 17 different positions There’s no difference in render time compared

to a regular light

Follow these steps to create a global illumination rig with spinning lights:

1 Create a hemisphere object and hit “f” to flip the polygons

2 Create a Luxigon object via Setup>Layout Tools

3 Select the Light Type and set the Color and Intensity options

(You can use any type of light you wish, but I prefer

ray-traced shadowed distant lights.)

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4 Send the scene to Layout and select your Hemisphere object.

5 Select the Convert Luxigons item from the Items>Lights drop-down (useUtilities>Additional in LW 7.5), and name your light rig set accordingly.Your light rig is created

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6 Select the Hemisphere polygon object In the Object Properties panel, selectthe Render tab and check the following: Unseen by Rays, Unseen by Cam-era, and Unaffected by Fog This will ensure that it does not appear in thefinal render.

7 In LightWave 8, use the Scene Editor to multiselect your lights (This is onlyavailable in LW 8.)

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8 Right-click and choose Select in view ports from the drop-down.

9 Adjust any settings you want to alter in the Light Properties panel, changinglight and shadow types and doing a series of render tests until you achievethe look you want

10 Select the parent object for your light rig Go to frame 1 and set the Headingfield to 60º (720/12, the number of sides in the hemisphere)

11 Open the Graph Editor and select the Heading channel Select Repeat fromthe Post Behavior drop-down

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12 Set Antialiasing to Enhanced Low or higher and activate Dithered in theMotion Blur drop-down.

13 Activate Ray Trace Shadows in the Render Options panel

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Notes on optimizing a scene:

n Reduce the number of luxigons you use by using less geometry during setup

n To smooth your ground plane shadows, increase your AA settings

n Use multiple colored lights in your scene to enrich the color space of thefinal render

n Use one key light to drive your primary shadow in your scene

Versions: 7.5-8

665 Eki Halkka | General Tips | Intermediate

Creating a Sun

Here’s how to create a basic spinning distant light sun

1 Start with a new, empty scene Take the default distant light and rename it

“Sun.” Reset its motion and rotation

2 Add two nulls to the scene and name them “Sun_handle” and “Sun_spinner.”Parent (“m,” parent item drop-down) the spinner null to the handle and thedistant light to the spinner

3 Go to frame one and rotate the spinner null’s bank 720º Create a keyframe(Enter) Open Graph Editor (Ctrl+F2) and select the bank rotation channel.Set Pre and Post Behavior to Repeat

4 The more you rotate the sun light, the bigger the light source’s simulateddiameter and softer the shadows Rotate the sun light by 0.5º at frame zero

on heading or pitch to roughly match the sun’s diameter, as perceived here

on earth

5 You can now rotate the handle null to aim your sun, treat the null as if itwere the distant light itself The spinning light trick is done, but there’s onemore thing to do As the spinning light trick relies on LightWave’s internalmotion blur calculations, you will need to turn it on in the Camera Optionspanel (Shift+C, p) Usually a sun will look good enough with low

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Spinning spotlights with shadow-mapped shadows and four distinct

light colors.

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antialiasing and normal motion blur, but if you make the spinning lightsofter, you will need to use higher settings.

For more information on spinning lights, see:

http://members.shaw.ca/phroggrafix/tutorials/spinning/spinning.htmlhttp://www.kolumbus.fi/erkki.halkka/plugpak/Tut/OC_Behind.html

http://members.shaw.ca/lightwavetutorials/lighting.htm

I have created a collection of LScripts that automate the creation of a variety

of spinning light rigs ranging from a basic sun similar to the above to a fullglobal illumination setup Have a look; you can use the scripts for free, as long

as you don’t mind a few nagging requesters!

(http://www.kolumbus.fi/erkki.halkka/plugpak/index.html)

Versions: 6-8

666 Dave Jerrard | General Tips | All Levels

Project a Procedural through a Spotlight

You can project a procedural texture through a spotlight using the ProjectedImage feature The trick is to open an image in the Image Editor and then applythe Textured Filter plug-in This will allow you to texture the image as though itwere a surface By applying a procedural like Ripples or Underwater, you canhave an animated procedural texture applied to the image, which would also ani-mate when it’s projected through a spotlight It’s a good idea to use a largeimage since the procedural texture will be bitmapped when it’s projected, andthe resolution will be the same as the image you’re using Use a large image thatonly has one bit plane (two colors) to get the largest resolution without eating up

a lot of RAM

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The following is a large 2000 x 2000 pixel image that has an Underwaterprocedural applied.

When this image is projected through a spotlight, it creates an animatedunderwater effect

Versions: 6.5-8

Shading Noise Reduction

If you’re using linear or area lights (or even shadow maps), radiosity, orcaustics, you might want to turn on the Shading Noise Reduction option in theGlobal Illumination panel This was added to help reduce the grain that fre-quently appears in images using these features On a typical frame it will add 5

to 10 seconds of render time to the end of each render pass What it really does

is perform a small blur to the shading buffer (which you can view separatelyusing the Render Buffer View image plug-in and the Image Viewer)

However, this can blur out small texture details, such as those caused by finebump maps, so you’ll have to determine whether to use it on a scene-by-scenebasis

Versions: 6.5-8

More on Shading Noise Reduction

Shading Noise Reduction can also be used to subtly soften ray-traced ows cast by distant, spot, or point light sources Again, this may have

shad-detrimental effects to fine textures, so you’ll have to test this for each scene

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Area Lights

When using area lights, a quality level of 3 will give you good results and isall you really need, especially if you’re using antialiasing This will save a fairamount of render time with little, if any, reduction in image quality

Versions: 6.5-8

Distance from Light vs Light Size

A good rule of thumb when using area lights is to make sure that the tance from the light to the smallest object is not less than the size of the light If

dis-a ldis-arge dis-aredis-a light is pldis-aced too close to dis-a smdis-all object, it will render with dis-a ldis-argeamount of grain and the lighting will look terrible, even at the highest qualitysetting When any surface is too close to an area light, it risks falling into a smallshadow area that surrounds the light for a short distance This is caused by theacute angles between the surface and the surface of the light At these angles, thearea light is mostly seen nearly edge on, and thus very little of its surface affectsobjects that are so close If you need to create a large soft light effect, considerusing an array of smaller area lights, or possibly even radiosity

Versions: All

Lens Reflections and Glow Behind Object

Reflections take place whenever a bright light enters a camera lens and, asthe name implies, reflects back and forth between the different lens elements Infact, they are artifacts that happen in the camera, and since they’re closer to thefilm plane than anything else that’s outside the camera, they will always appearsuperimposed on top of everything else in the scene An object could neverblock out part of a reflection like this* It would have to be inside the camera to

do so If you want to have a light glow behind an object and have it cause lensreflections, use two lights — one with Glow Behind Objects turned on and theother to cast the reflections This second light should also have Fade BehindObjects turned on

ÜNote: This is also true for the Random Streaks option, which are caused by smudges and scratches onthe camera lens

*Technically, an object can partially block lens reflections in a real camera, butnot the way it happens in LightWave In a real camera, each reflection wouldhave a silhouette of the object cutting into it For example, if a man stood on ahill in the distance, with the sun behind him, he would be a black shape againstthe sun The shape of the remaining visible part of the sun would be the shapethat’s reflected in each lens

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The following image is wrong The only way this could happen is if thespace station were floating in front of an image that had this lens flare.

The unobstructed lens reflections correctly obscure the station

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Here, a shadow map with the size set to 200 looks very chunky and

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way the direction of the key light, fill light, or back light can quickly be

changed Also, use Load From Scene to load this rig into any new scenes andthen use the Master Light Kit null to scale the rig to fit that scene

Versions: 7-8

674 Rob Powers, Steve Warner | General Tips | Intermediate

Changing Color Display on Lights

I prefer to change the color display settings on my lights to clearly identifythe type of light in Layout That way I can easily find my key light, fill light, andback light in any viewport at a glance I typically use red for the key light, lightblue for my fill light, and orange for the back lights The specific color choicesare not important but you should try to maintain consistency in your light kits.Developing a “color coding” system like this for your lights will save time whenreusing light kits and working with larger projects where you must work withnumerous scenes

Versions: 7-8

ÜNote: You can change the color display settings for objects, lights, cameras, etc., from the Scene Editor

675 Rob Powers | General Tips | Intermediate

View Lighting Effects One at a Time

When doing the initial lighting on your scenes it is often helpful to view theeffect of the lights one at a time This will allow you to easily see the influencethat each light has on the overall “mood” of the scene and will help you under-stand what adjustments are needed Worley’s G2 lighting plug-in will do thiseasily with the click of a button in the G2 preview window However, you caneasily do this in LightWave by just turning down the intensity of all other lights

or by unchecking Affect Diffuse and Affect Specular in the Light Propertiespanel

Versions: 7-8

The Size of an Area Light Will Influence How Fast the Scene Will Render

You can simply select the area light and then use the transform and scaletools in Layout to resize it Often smaller area lights positioned closer to theobjects will work well and will render much faster Also, larger area lights canincrease the amount of “shading noise” or speckles in the renders In that case,checking Shading Noise Reduction in the Light Properties Global Illuminationpanel will help reduce this

Versions: 7-8

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Adjust Shadow Colors

When trying to set up realistic lighting, don’t forget to adjust the light’sshadow color in the Light Properties panel to a more appropriate color for yourenvironment If you are doing a shot on the moon, the default solid black colormight work well For most other environments, the shadows should usually beadjusted to match the ambient and bounce lights in the scene For example, theshadows in many exterior day shots would have a slight blue tone because of thelarge blue sky ambient light present

it It’s important to give the light falloff so it doesn’t affect any other surfaces orexclude it This will help darken the inside of the mouth This is also a great way

to darken parts of a room in corners, for example If a spotlight is used as a ative light, the dark area it creates can be “sculpted” or shaped by projecting animage through the spotlight

spotlights with only specularity turned on You can also have the lights only

affect the eyes These eye lights can also project images onto the eyes Be sure

to parent the lights to the character’s head bone so they follow the characteraround

Versions: 5-8

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680 Patrik Beck | General Tips | All Levels

Never Use Several Pure White Lights to Light a Scene

Changing the color value of the lights in the scene by just a few notchesmakes it much more natural and pleasing to the eye

Versions: All

Using Negative Lights

Lights can have negative values; this means they will actually suck light out

of an area It is a common problem that many computer-generated images areoverlit Using a negative light with falloff is really handy for darkening corners

of a room or the underside of things If the negative light is tinted, say forinstance a blue light with an intensity value of –50%, it will suck the blue com-ponent out of the surrounding lights

Versions: All

Understanding How Linear and Area Lights Can Cast Soft Shadows

You know that linear and area lights can be used to generate soft-edgedshadows, but in practice the shadows can be tricky to control It helps if youimagine a linear light as having a point light at each end, and an area light hav-ing points at the four corners The shadows those points cast show the angles ofthe shadows The bigger the lights, the wider apart the shadows will spread

Versions: All

Working with Caustics

Caustics are the specks of light that bounce off of a reflective surface Oftenthe lights illuminating the scene do not throw the caustic specs where you wantthem To give you more control, clone the light that is generating the causticsand have it affect only caustics Reposition the light to give it a more desirablecaustic angle

Versions: All

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Faking Radiosity Effects

You can fake radiosity effects by using settings in the Light Properties panel.Using either point or spot lights, go to areas where there is a strong color onwhich you would expect to see some bounced illumination, say a red wall Add

a light with enough falloff so that the light does not reach very far Set the lightcolor to match the wall Use Affect Diffuse, and turn off Affect Specular, AffectCaustics, and shadows for that light If possible, exclude the red wall from thatlight’s influence These settings are necessarily subtle but can achieve pleasingvisual effects

Versions: All

Caustics

Caustics are caused by refraction in transparent surfaces and reflection, but it

is not necessary to activate Trace Reflection or Trace Refraction for there to becaustics

Versions: All

Watch Out When Using Distant Lights That Cast Shadows

Beginners will often grab the default scene light (which by default is a tant light) and place it inside an object like a house This leads to the oddsituation where it will cause the house to cast a shadow from the outside whenray-traced shadows are turned on Distant lights start at an infinite point behindthem and go to an infinite point in front of them, following a path parallel withthe angle of the light item, which means the location of the light itself is incon-sequential as far as lumination and shadows are concerned, only the rotationalangle of the light For lighting enclosed spaces, it is better to use any type oflight setting other than distant

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Use Light Exclusion, Often Often Often

Many people don’t take advantage of this hugely useful feature Excludinglights let you handpick which objects are affected by a light and which aren’t.This gives you pinpoint control over your lighting setups and allows you to havelights serve very specific purposes in a scene

Versions: All

Point Lights and Distance Falloff

It’s almost always a good idea to turn on distance falloff of some kind whenyou’re using a point light Otherwise, the light beams often end up hitting poly-gons that you may not have wanted them to

Versions: All

Don’t Think About What a Light IS — Think About What It Does

It’s easy to think about a light in LightWave for the type of light it is — as adistant, point, spot, and so on In fact, that’s sort of the only way most peopledescribe or think about lights Clear your mind, though, and expand your light-ing consciousness

Look at every light in your scene and ask yourself What does this light do?What is its purpose? Use that as your starting point, and you’re approachinglighting in an artistic (as opposed to technical) way It also keeps you from try-ing to have a light do too much in a scene If the purpose of the light is to, forexample, bring out the detail in the shadows of a spaceship — well, maybe that’senough Maybe it’s a mistake to make the light try to illuminate the planet in theshot, too

Find the purpose of the light — what it does — and what kind of light itshould be, how bright, what color, shadows or not, and so on … all those ques-tions answer themselves

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Study Good Lighting for the Result, Not the Technique

Lighting in LightWave and lighting in the real world have almost nothing incommon Lights in LightWave aren’t realistic at all Things that gaffers and cin-ematographers and photographers use — like diffusions, spot metering,

exposure controls, flags, C stands — have no counterparts in LightWave So,lighting in LightWave isn’t like lighting in the real world — but reality is reallyoverrated

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That doesn’t mean you shouldn’t study good lighting by watching movies orlooking at photos These reference sources are crucial to give you ideas — aboutthe results Achieving those results in 3D, however, is a totally different process.

A popular method of rendering models to exploit all the details is to use amethod commonly known as “clay rendering,” whereby you create a very evenlighting situation that creates soft shadows on your model It is referred to asclay rendering because the final look is very soft and devoid of specular high-lights and looks very much like a clay sculpture

To create this kind of lighting environment you need to go to the Global mination panel in Layout First you should change the Global Light Intensityvalue to 0% This means that the lights in the scene will no longer affect thescene in any way, as the renderer will completely ignore them Then you need toswitch on Radiosity, using preferably Monte Carlo or Interpolated as the

Illu-radiosity type Choose an appropriate Intensity setting, depending on howbrightly lit you want your scene to be

Using radiosity will instead light the scene using bounced light within it, and

to help this along you need to add an environment to your scene You can do thiseither by setting your Backdrop Color to white in the Effects panel or by using

an HDR (high dynamic range) image in Image World

Using a white image in the backdrop will light the scene evenly with a whitelight, while using an HDR image (commonly known as “light probes”) lights the

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scene subtly with the colors that are within the image You can load HDRimages into Image World under the Backdrop tab in the Effects panel.

Creating an environment like this for the scene ensures that the radiosity willhave a great effect on the model, creating a nice, even lighting in the scene thatshows off all the details of your models

Versions: 6-8

8 Newbie Note (Robin Wood): Image World will only work with pre-loaded images, so if you don’tsee the image you want in the list, load it using the Image Editor in the top-left corner of the screen It willthen appear in the list so you can choose it

693 Patrik Beck | Global Illumination/Radiosity | All Levels

Radiosity, Diffusion, and Luminosity

Radiosity only works with the surface attributes of diffusion and luminosity.Specularity has nothing to do with it The higher the level of diffusion, the morelight will bounce off of it and illuminate the surrounding area Making a surfaceluminous will make it a very soft light source when radiosity is turned on Theluminous object can be set to Unseen by Camera and still illuminate the screen

It is sometimes necessary to crank the luminosity level up to several hundredpercent in order to get visible results from the luminous radiosity illumination

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694 Eki Halkka | Global Illumination/Radiosity | Beginner

Recreating the Sky

Practically all the natural light you see outdoors is either direct, reflected, ordiffuse sunlight (I’m discounting stars and fireflies, as their contribution is quitesmall.) Even moonlight comes from the sun Even though direct sunlight is verydominant when present, it’s just as important to take the diffuse light intoaccount In most cases, the reflected light is much less important

The sky is a very big, hemispherical diffuse light source So, what would bethe best ways to reproduce this?

Let’s examine a few options from quick and ugly to slow and beautiful…LightWave’s internal ambient light (Shift+L, p, Global Illumination) is avery quick but not too nice-looking option We are so used to watching thingsunder outdoor lighting that we expect diffuse lighting to come from above.LightWave’s ambient light has no direction whatsoever; it just adds even lumi-nosity to all surfaces in the scene

A simple and fast way to improve things is to add two distant lights to plement LightWave’s default 25% ambient lighting Turn shadows off for bothlights Rotate the first light so that it points directly down (H0, P90, B0), and setits intensity to 25% This light mimicks the light from the sky, so you may wish

com-to give it a slight blue tint Rotate the next light com-to point up (H0, P–90, B0), andset its intensity to –25% This negative light will suck away ambient light fromthe bottom of the items in the scene That’s it — the result is a lot more convinc-ing than the default LightWave ambient lighting The polygons pointing up willreceive 50% ambient light and the polygons pointing down will receive 0% Youcan tweak the settings to get a different ambient solution If you need soft ambi-ent shadows, you can try replacing the sky distant light with a shadow mapspotlight placed very far above the scene The shadows won’t be accurate, butthey are often good enough to sell the scene And this setup is very fast torender

The next way to create overall ambient solution is to use a hemisphericalarray of lights surrounding your scene When you have enough of these lights,their shadows will blend together and give a rather believeable radiosity-likeillumination to your scene A similar lighting rig can be created using distantlights with varying rotations And yes, the spinning light trick can be used tomultiply the apparent number of these lights A variation of this technique isoften the best bet when comparing quality vs speed

Area lights can also be used as skylights Make the area light big, rotate it90º on pitch, and place it low, just over the items in your scene The results lookvery nice but it is slower than the previous methods The bigger the light is, thebetter, slower, and grainier the results You can reduce the grain by turning onShading Noise Reduction in the Global Illumination panel and using motionblur; this helps reduce grain with radiosity and soft shadow maps too

Finally, you can use radiosity for the ambient light in your scene The resultsare beautiful, but there’s often a hefty punishment at the rendering stage; theaccurate calculations take a lot of time Most of the time using Backdrop Only

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radiosity is the best option if speed is an issue but you still need to use “real”radiosity.

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696 Eki Halkka | Global Illumination/Radiosity | Beginner

To HDRI or Not to HDRI

Even though you can use radiosity to fully light your scene, it is at its bestwhen it’s used to simulate diffuse and relected “ambient” light Many HDRimages have small high-intensity areas, which will cause the radiosity solution

to look rather grainy unless extremely high-quality radiosity settings are used Iusually use a blurred normal dynamic range version of the environment forradiosity, giving the overall ambient light, and use regular lights for the more

“tight” light sources This combined with HDRI environment for the reflectionsgives excellent results

back-of how every point on the object is easy to “access” for a light ray

You may consider this “accessibility” map as an “object diffuse map,” which

is independent from the environment since it’s a property of the geometrytopology

Using Surface Baker you can bake this map either on a texture or on points

if you have enough

You can then reapply the baked accessibility map on the diffuse channel ofyour object, or, if you already have diffuse textures applied, you can multiplythem together in the Texture Editor using layers

To create this map you need simply to set a flat white background color(255, 255, 255), apply Surface Baker with only Bake Illumination on, and turnRadiosity on, using the Backdrop Only radiosity type

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Also, remember to deactivate any other light in the scene and set AmbientIntensity to 0% to avoid overbrightening and falsing the results.

Here’s an example of an accessibility map applied to an object:

ÜNote: Silhouette edges have been added just so the object’s shape is recognizable

You can modulate the brightness of the map before baking it by settingRadiosity Intensity higher or lower than 100%

With standard lighting and the accessibility map applied, your objects willalways keep that “solid” look without using radiosity every time

Versions: 6-8

698 Dave Jerrard | Global Illumination/Radiosity | All Levels

HDRI Rendering with Radiosity

Instead of mapping an image on a skyball object for HDRI rendering withradiosity, map the image on the Textured Environment instead This will allowyou to use the Backdrop Only radiosity method, which will render much faster.Even if you use Monte Carlo or Interpolated radiosity, this will speed renderingbecause there’s no longer a skyball object to figure into the radiosity

calculations

Versions: 6.5-8

Backdrop Only Radiosity

For most scenes using Backdrop Only radiosity, you can lower the Rays PerEvaluation to 3 x 9 and get very good results as well as good render times.Higher values will increase the render times significantly, while lower valueswill create very grainy images

Versions: 6.5-8

Keep Detailed Textures to a Minimum

When working with Monte Carlo or Interpolated radiosity, try to keepdetailed textures to a minimum Every time light bounces from a surface, thetexture for that surface needs to be calculated to find out what color that ray will

be Remember that every ray that comes from the camera to a surface must firstfind out the color of the surface at that point It will also be split into severalevaluation rays, and each of these will be traced out in random directions When

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these hit a surface, the texture at that point must also be calculated If the pointwhere one of these rays hits is significantly brighter or darker than the others, itcan cause a bright pixel on the originating surface (the one that fired the evalua-tion rays) Textures with lots of detail will return a lot of these brighter or darkerrays, and this is what causes the grain in radiosity renders In addition to thegrainy appearance, the extra surface calculation will add a lot of time to the ren-der Try comparing the quality and render times of the same object with texturesand without The simpler surfaces will render faster and tend to look better.

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701 Gerald Abraham | Global Illumination/Radiosity | Intermediate

Realistic Shadows with HDRI

Using HDRI or radiosity does not automatically exclude the use of otherlights in a scene Often when recreating a scene with a bright key light such asthe sun, you’ll need to use an area or spot light along with radiosity/HDRI tosimulate a realistically cast shadow Although HDRI can provide nice, diffuselighting and reflections, the shadows are not always accurate

Versions: All

702 Policarpo | Global Illumination/Radiosity | Beginner

Preview Global Illumination Renders

Preview Global Illumination renders at low sampling settings to get a feel ofwhat the final piece will look like Turn on Shading Noise Reduction in theGlobal Illumination panel to smooth out the preview renders

Versions: 7-8

703 Gerald Abraham | Global Illumination/Radiosity | Beginner

Exclude Transparent or Reflective Objects from Radiosity Hit

On occasion, it’s a good idea to exclude transparent or reflective objectsfrom a radiosity hit For example, when creating headlights for a car, neither thecovers nor reflectors rely on diffuse shading to sell the surface Excluding theseobjects might save you quite a bit of render time

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704 Policarpo | Global Illumination/Radiosity | Beginner to Intermediate

Shading Noise Reduction

Use Shading Noise Reduction in the Global Illumination panel to reduce thegraininess of GI renders This in combination with various AA settings helps tode-grain your final render Use higher AA settings to reduce the need for highersampling rates Render scenes in passes to ensure the ability to tweak your finalrenders in post

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ÜNote (Robin Wood): You may want to test this in your scene first to see which is more efficient andthen use that one (higher AA or higher sampling).

To create a field of fake flares:

1 Create a quadrangle on the XZ plane and make its normal facing +Z

2 Send the object to Layout and map the flare image on it

3 Set the desired color, set Luminosity to 100% or more on the surface, and setDiffuse to 0%

4 In the Advanced Options tab, set Additive Transparency to 50% (you cantune this with some quick test renders)

5 In Motion Options, set Target Item to Camera

6 Clone the plane as many times as you want (50 would be a good number toshow off)

7 Keeping all clones selected, add the first plane to the current selection (orsimply reselect all the fake flares again using the Scene Editor)

8 Start the Keyframer generic plug-in (Scene>Generics>Keyframer)

9 In the Standard tab, select Randomize/Jitter Keys

10 Just click “OK” on this panel (select range and objects)

11 In the next requester, check Object Position on and set a Max Value (10 ifyour plane is 1 square meter)

Now you can navigate through all those light glows always facing the era If you want them to fade in distance, just turn on the Distance Dissolvecheck box in the Object Properties>Render tab and set a maximum distancebefore cloning the rest of the planes

cam-Version: 7

706 Kevin Phillips | Flares | Beginner

Quick Blinking Fairy Lights

Say you have a simple logo project with an array of lens flares that you need

to blink on and off continuously, all at the same time Easy, right? You could just

create one light, edit the flare intensity with the Graph Editor, and then clone it afew hundred times

However, then your client asks you to change the timing of the lights, maybeadd in a couple of extra blinks, etc.! Sure, they may all be doing it at the sametime, but you’re going to have to update hundreds of lights

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Instead of editing all those lights, why not control the overall blinking usingthe Global Illumination panel, found by clicking on the Global Illumination but-

ton at the top of the Light Properties panel? You can quickly edit one graph for

the Global Lens Flare Intensity value and update all lens flares at the same time!

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708 Kevin Phillips | Flares | Beginner

Shrink and Grow

Lens flares in general tend to maintain their size, which in some cases may

be fine However, what if you planned to use a flare to represent that giganticglowing meteor at the front of a smoke trail, or perhaps those blinking lights ofthe space freighter that flies past the camera?

If the lens flares stayed their same size no matter where they were, the effectmay not work for your audience

Luckily, you can adjust the size of the lens flare over distance by setting theLens Flare option Fade with Distance in the Lens Flare Options panel You alsoneed to set the Nominal Size This value represents the distance from the camera

at which the lens flare will be at 100% its normal size The lens flare will thenshrink as it gets farther away from this position and enlarge as it gets closer.But how can you be sure that this effect is going to work without producing

a lot of test renders to check? Activating OpenGL Lens Flares in the DisplaySettings panel will allow you to visually check your fade settings in the Cameraviewport in real time

Versions: 5-8

709 Patrik Beck | Flares | All Levels

Using Lens Flares in Place of Volumetric Lighting

Lens flares can be used in place of volumetric lighting In the Lens FlareOptions panel, turn off all the options except Central Glow Set the Flare Dis-solve level between 25 and 75% This creates a big, soft, glowing area aroundthe light, very similar to a street lamp on a foggy night As opposed to volumet-ric lighting, it renders really really fast

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Creating a Shock Wave Effect

For a really fast shock wave effect, use the Central Ring function in the LensFlare Options panel Create an envelope for Ring Size that starts at 0.0% andexpands to 150% or until it expands completely off the screen To tilt the shockwave, turn on the Anamorphic distort function Increase the level to flatten theshock wave

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Lens Flare Colors

To change the color of a lens flare, you must change the color of the light

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Matching Flare Intensity

Although the light color will affect the color of the lens flare, the light sity is completely independent of the intensity of the lens flare A simple way tohave the intensity of the flare match a changing light is to copy the light inten-sity envelope and paste it to the flare intensity graph Open the Light Propertiespanel, go to the Light Intensity setting, and click on the “E” button to open theGraph Editor for the light intensity Right-click on the Light Intensity channellisting and select Copy Once you have added your keyframes for the light inten-sity, close the Graph Editor, click on the Lens Flare Options button, click on the

inten-“E” for Flare Intensity to open the Graph Editor, and paste the Light Intensityenvelope onto the Flare Intensity envelope

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Creating Different Effects with Lens Flares

To create a ghostly ectoplasmic type light, change the light color to solidgreen In the Lens Flare Options panel, use only Central Glow, and turn off Cen-tral Ring and Red Outer Glow Activate Random Streaks and in the RandomStreaks section enter these settings: Intensity 150%, Streak Density 5%, andStreak sharpness 0.5% Keyframe the flare to move across the screen When it isrendered, you will see the green streaky glow twist and evolve

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Saving Flare Settings

It is not currently possible to load and save lens flare settings, but you cansave the light with the settings to load into another scene Under the Save func-tion you have the option to Save Current Light This actually saves a scene filethat contains only the currently selected light To load that light with the lens

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flare settings, select the Load Items From Scene option and click Yes to theLoad Lights? requester All the lens flares, properties, and keyframed motions ofthe original light will be loaded.

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Intensity Setting

The Intensity setting controls the size of the lens flare along with its

inten-sity To get a very intense but small lens flare, duplicate the initial flare andparent it in place to the first light You may want to set the Light Intensity for theduplicate flare to 0 so it has no effect on the lighting

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Adding Sparkle

Using the Lens Flare Star Filter with rotation is a great way to add a

“sparkle” to a scene Use the 6+6 setting and set an envelope for the RotationAngle with an offset repeat so it will be constantly spinning Use an envelope onthe Intensity setting to bring the sparkle in and out

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Fading Lens Flare

For lens flares to behave in a realistic manner, they need to fade with tance Unfortunately, the balance between Nominal Distance and Intensity is not

dis-a very intuitive setting The best wdis-ay to figure out the best Nomindis-al is to use theOpenGL Lens Flare option in the Display Options panel Although the OpenGLlens flares are not always displayed accurately in Layout, it does give a goodsense of scale and intensity of the lens flare If the plan is to use multiple lensflares, like streetlights or headlights going over a bridge, find the approximatesetting for the first flare and clone it

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Glow Behind

When lens flare lights go behind an object, and Fade Behind Objects is vated, the lens flare instantly blinks out For a more natural light spill around theedge, clone the original flare, dial down the intensity, increase the dissolve, anduse Glow Behind Objects Now when the lens flare moves out from behind theobject, a softer glow will precede the full intensity of the full flare

acti-Versions: All

Most Important Lens Flare Tip Ever

Never use the default Lens Flare settings It increases rendering speed

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Volumetrics

721 Geoffrey Kater, William “Proton” Vaughan | Volumetrics | Beginner

The Volumetric Spotlight Cheat

The volumetric spotlight cheat is probably the oldest trick in the book, butit’s still worth mentioning Create a cone in Modeler and parent it to a spotlight

in Layout Match the spotlight’s cone angle to that of your cone model Texturemap a black to white gradient in the transparency channel on that cone Thereyou have it — a great cheat that saves on render time and adds a dynamic light-ing effect

Versions: 5-8

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722 Kevin Phillips | Volumetrics | Beginner

Fast Light Beams

If you need quick light beams, such as streetlights, consider using the SpriteMode option in the light’s Volumetrics Options panel It’s fast, but there aresome caveats: It doesn’t work well with textured volumetrics or volumetricshadows

However, it’s great for simple beams and basic volumetric lighting

Versions: 7-8

723 Leigh van der Byl | Volumetrics | Intermediate

Speeding up Volumetric Lighting

We all love volumetric lights But they sure can take ages to render, as youwill have discovered if you have used them much One way to make them ren-der a lot faster is to render them separately Rendering them separately alsogives you more control over their appearance

What you do is make a duplicate of the scene that you want to add ric lighting to Save all the objects as duplicates as well, because we will bechanging their appearance and you don’t want to overwrite your precious tex-tured characters and objects I usually save the scene and objects with a suffixsuch as “volumetric_pass” or something to that effect (sensible file naming is sovery important, especially in a crazy production environment!)

volumet-The first thing you need to do is change all the surfaces in your scene so thatthey are all totally black Matte black That means no specularity, no glossiness,

no reflection, nothing You can do this quickly by simply selecting all the faces in your scene, taking the levels in all channels to 0, and Shift-clicking onthe “T” to remove all textures You don’t want these surfaces to do anythingwith the light

sur-Once you have your totally black scene, set up your volumetric lighting asyou want it Remove all other lighting from the scene, so that the only lights thatare active are the volumetric ones Render the sequence/image out You’ll noticethat it renders much faster this way

Once you have your sequence or still rendered image, all you need to do istake it into a compositing package (such as Discreet Combustion, Adobe AfterEffects, etc.) or into a painting application like Adobe Photoshop (if it is just astill render), and place the volumetric render on top of the render without thevolumetric lights Simply use a blending mode like Screen or Dodge to blend thevolumetric lighting with the rendered scene below it Any blending mode thatwill ignore the black in the scene will work This way you have much greatercontrol over the volumetric beams because you can play with their intensity sep-arately (as they are on a different layer than the rest of the scene) and you canalso color them as you wish

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724 Kevin Phillips | Volumetrics | Beginner

Soft Smoky Lights

If you need a fairly convincing smoke effect for your light volumetrics, sider using one of the Smoky procedurals After applying the procedural, set itsTurbulence value to something other than 0 to animate the smoke effect

con-Don’t forget that you can use VIPER and create a preview to test the effectquickly without the need to render a test

Versions: 7-8

Shadows

725 Leigh van der Byl | Shadows | Beginner

Gobo Lighting

A very effective way of creating the sense of an environment in a render is to

use a technique known as gobo lighting This technique, used a lot in theater,

involves placing a plate, called a gobo, in front of a spotlight This plate, which

is usually made of metal, is cut to a specific shape, so that when light is castthrough it, it casts those shapes onto the stage By placing a plate cut into theshape of trees and leaves, you will get an effect of light shining down through acanopy of trees on the stage, which gives viewers the impression that the scene

is surrounded by trees without having to actually place trees around the stage

Doing this in LightWave is very simple (as seen in the previous image), asspotlights have the ability to project images All you need to do is create a spot-light, go to its properties panel, and load an image (preferably a high-contrastblack-and-white image) next to the Projection Image label

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This is an extremely useful method of creating the sense of environment rounding your characters and objects in renders, as the shape of shadows canadd a lot of information to viewers about the scene, even if those items castingthe shadows are not actually visible in the picture themselves.

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Tiêu đề	General Tips
Tác giả	Policarpo, Lee Stranahan, Geoffrey Kater, Eki Halkka
Trường học	Not Available
Chuyên ngành	LightWave 3D
Thể loại	not available
Năm xuất bản	not available
Thành phố	not available

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Số trang	65
Dung lượng	1,23 MB