LightWave 3D 8 Lighting Wordware game and graphics library phần 5 docx

When using this technique, the lens flare takes on the color of the light. In this case I used point lights with a color of 255, 0, 0. One of the great things is that the lens flare intensity is independent of the light intensity. So you can turn the light intensity off and still have a great lens flare. It is a very versatile little technique that can be used in innumerable ways. Picture street lamps as viewed from a helicopter. Or imagine how useful this effect might have been in the days of Blade Runner when a night- time cityscape was composed mainly of bright point source lights just like this. This technique is by far the best use I have found for lens flares in LightWave. But you may very well find a place where you need a real lens-reflection type lens flare. Go ahead and use it. But remember, as with all effects and techniques, subtlety is usually the key to success. Recently I set up a scene with 15 lens flares interacting with five render passes of particles to create a magical effect. The lens flares were nothing more than drifting light sources floating around in space. One of the double-edged swords in LightWave is that the light sources them - selves are not visible. This is good because it means you can place a light anywhere on the set, including directly in front of the camera, and not worry about seeing it. On the other hand, when you want to see the light source, you’re out of luck. This is where lens flares come in handy. If you turn off all the rings, streaks, and whatnot, you are left with a sin - gle intense point where the light’s pivot point is. This is a great visible light source that is useful for all sorts of effects and situations. Chapter 15 ······································ 192 Figure 15.4: Using lens flares. (See color image.) My last piece of advice about lens flares is to use them sparingly and wisely. Overuse of this effect is a dead giveaway that the work is CG. You should now understand the use and purpose of lens flares in LightWave. Remember, it is usually the creative and uncommon uses of these tools that get you noticed as an artist. ······································· Lens Flares 193 Chapter 16 Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters This chapter discusses a few of the more popular tools used in Light- Wave for lighting and shading. There are many more out there. Some are expensive, some are cheap, and some are even free. If the tool you need isn’t listed here, it is almost certainly out there somewhere. Do a web search, but first check www.Flay.com. Because of LightWave’s open architecture, there seems to be an endless stream of new plug-ins and LScripts for artists to explore and employ in their work. Of course, these new features go far beyond light - ing, but the mere possibilities in lighting alone are mind-boggling. Usually a discussion starts on one of the mailing lists between a few art - ists experiencing the same problem under similar circumstances. Next thing you know, some pr ogramming brainiac has come up with some solution. Nine times out of ten it’s a freebie too! That community spirit is one of the things that makes LightWave great and guarantees its con - tinued presence in the world market of prime animation softwar e packages. There are a number of tools available — some are commercial, some come with LightWave, and some are freely available on the web. I’ll go through a few of the most common and best-known ones here. Don’t let that stop you from discovering others. If there’s one thing I’ve 194 learned about LightWave it’s that there’s always something new and dif - ferent to learn just around the corner. I do not go into detail on the use of most of these plug-ins but I do provide brief descriptions and example renders where I can. These tools can all be researched on the web at www.Flay.com and elsewhere, and in the LightWave manual and on the LightWave web site, www.newtek.com. It’s also worth your while to keep an eye on Worley Labs at www.wor - ley.com. Worley always seems to be coming up with handy, rather mind- blowing lighting tools these days. It is worth your time to check out all these sites and any others you can find; they may save your bacon. Bear in mind that most lighting plug-ins are post-process filters that alter the rendered image. After you’ve done your lighting, set positions, intensities, colors, and whatnot, you can still work on your image. Because the final render is just a two-dimensional image made out of pixels, you have all the tools of a painter and many, many more. Learn them, love them, use them. These are some of the details that separate good artists from great ones. Also, some of the tools mentioned here are free and available on the web. Others have a commercial cost, sometimes too great for hobbyists, freelancers, or small houses. All I can say about the expensive ones is that if you’re doing a job where you really need this tool, you should be able to justify it within your budget. If your client isn’t paying you enough to comfortably acquire the tools you need for the job and still make a profit, then your client isn’t paying you enough. Shadow Designer 2 Shadow Designer 2 by evasion 3D (www.evasion3d.com) was designed to simulate soft real-world type shadows that are difficult or even impos - sible to simulate using simple ray-traced lighting instruments like spotlights, point lights, and distant lights. Evasion states in its documen - tation that this plug-in is intended to be used for subtle, soft lighting effects, although it can produce hard shadows if necessary. One of the greatest advantages to Shadow Designer is that you can apply it on a surface-by-surface basis so that unlike radiosity or area lights, the soft shadows are only calculated in areas specified by the artist. SD also pro - vides the capability of applying multiple shadow layers from multiple lights, allowing you to “paint” with your shadows and making it possible for you to achieve very custom lighting and shadows not possible within LightWave alone. While the first version of Shadow Designer did, in fact, produce very nice soft shadows, it was often slower than a beautiful soft shadow created using an area light. Evasion boasts a speed increase in ·················· Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters 195 the current version (2) of 300% to 2000%, which would make it faster than area lights and much faster than radiosity. For a soft shadow solu - tion, this software is worth a look. It doesn’t come cheap, though, especially if you are a small operation. Figure 16.1 was rendered from the Shadow Designer 2 tutorial files sup- plied with the plug-in. The render using Shadow Designer took 18 minutes and 18 seconds. Figure 16.2 is the same scene using an area light and ray tracing instead of Shadow Designer. While the final results are comparable, the LightWave-only render took 31 minutes and 53 sec- onds. That’s 74% longer. Shadow Designer takes a little time to tweak, but the render time savings are significant enough to make the front-end time investment well worth it for a long render. Chapter 16 ······································ 196 Figure 16.1: An image created using Shadow Designer. (See color image.) Figure 16.2: An image created using area light and ray tracing in LightWave. (See color image.) G2 G2 from Worley Labs is a tool that will change your lighting process. With its interactive preview, you will be tweaking lighting and texture settings on the fly and watching them update near real time in the pre - view window — sort of like V iper on steroids. If you haven’t already heard of G2, you must be dead. If you haven’t tried it, you really, really should, if you can afford it. As with other Worley Labs plug-ins, it comes at a high price for small houses or freelancers. But the logic is, if you really need it for a project, you should budget for it. It’s worth it and will pay for itself in time saved on your first project. G2 features the following: • Sub-surface scattering • Optimized human skin shader • Interactive compositing • Output gamut and color adjustment • Light grouping • Noiseless area light shading • Radiosity adjustment • Proper glass refraction without duplicated backside polygons • Edge effect tools • Anisotropy • Photo “shading de-baking” for mapping ·················· Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters 197 Figure 16.3 Figure 16.4 According to the web site, all of these features show their exact pixel-accurate effects in real time using the new G2 preview system. (Sounds like what Viper was supposed to be.) Steven Worley of Worley Labs describes G2 this way: “G2 is a different beast. It’s not a shader like Gaffer; it’s a system of plug-ins that kind of interlock into LightWave to become symbiotic with it. There are Master class plug-ins to ‘run’ everything, Generics for commands, a shader for flagging surfaces, and a pixel filter for applying effects and post-processing. The goal of G2 was beyond Gaffer; it was more of ‘LightWave needs an improved inter - face for lighting, and it needs to do things totally differently. Can we make it happen?’ As an experiment I experimented with a texturing preview system in ‘Disgust’ a year ago, and that worked well. So I spent months and months planning a whole system for replacing LW’s system. And that’s what became G2. The name ‘G2’ is unfor- tunate in many ways; it’s more of my laziness since I didn’t know what to call it. :-) “But the cool thing about G2 is that it’s a whole FRAMEWORK for dealing with rendering, lighting, and shading effects, and one that’s turned out REALLY well. This is cool because now, starting with this framework which is powerful and accurate, I can add more and more capabilities into it, like new light types, new shading mod- els, new processing effects, new rendering methods, and so on. The current lighting and shading tools are just sort of the default obvious extensions and what I do with G2 UPDATES will be very interest- ing. “I’m especially eager to merge G2’s system with Sasquatch, allowing for a Big Change in how users interact with fur and hair. I haven’t even started that yet, but I’m looking forward to that.” After using G2 for feature work I can attest to the fact that this tool has completely changed how I work. The “old” way of achieving final looks for the render was to approximate your settings, hit F9 to render out a test render, examine it, make some adjustments, hit F9 to render out another test render, and so on. If your frames take any significant amount of time, you can imagine how the artists’ time soon becomes spent mostly waiting for frames to render so they can make a quick adjustment, then sit there waiting for the next render. With G2, you ren - der out your frame once, and then make all your tweaks and adjustments in G2. As you are making the adjustments, they are interactively updat - ing in the G2 preview window. Chapter 16 ······································ 198 One of my favorite features of G2 is its area light shadows. G2 uses its own rendering engine to calculate area light shadows, and you have complete control over the shadow quality. G2 area light shadows are much cleaner than those from LightWave alone, although they take slightly longer to render at higher quality settings. Check out the Worley web site at www.worley.com if you haven’t already, and take a look at the session videos — they will blow your mind. Overcaster Note: At the time of publication, Eki’s PlugPak for LightWave 8.0 was still under construction. The most current version of Eki’s PlugPak can be downloaded from www.kolumbus.fi/erkki.halk - ka.plugpak. We decided not to put the PlugPak on the CD this time since Eki will have added new, amazing features by the time you read this, and the one on the CD would then be out of date. So why waste the space? Please download Eki’s PlugPak if you wish to follow along with the tutorial. Overcaster originated when a LightWave artist named Eki Halkka decided to automate the “spinning light trick” by writing an LScript. It is now a sophisticated set of LScripts that you can use to simulate global illumination. The results of Overcaster are often of sufficient quality to replace Background Only global illumination while rendering many times faster. For those unfamiliar with the spinning light trick, the idea was born out of the inadequacy of distant lights’ ray-traced shadows, which are much too hard-edged to be realistic. A number of artists have been cred - ited with inventing this technique. The principle is that if you spin a light one whole rotation per frame with motion blur on, then the light will behave like many lights from many directions. Here’s the LightWave manual’s description of how it handles motion blur: “LightWave simulates motion blur by producing a number of semi-dissolved images of a moving object. In the Normal mode, the number of images is determined by the number of antialiasing passes. In fact, you must have some level of antialiasing in order to use motion blur. The Dithered mode greatly enhances the quality of the effect by doubling the number of images.” To fully understand how motion blur works, please see the LightWave manual. For more on Overcaster, I turn over the quill to Eki himself, ·················· Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters 199 who was kind enough to take time out of his schedule to write a descrip - tion of his great tool as well as a short tutorial on its use. Overcaster and Spinning Lights Overcaster scripts, which are a part of Eki’s PlugPak, r ely on three light - ing tricks that are rather well known by experienced LightWave users. First and most important is the spinning light trick. The others are the use of morph mixer and channel follower for controlling light proper - ties with sliders and the use of duplicated lights with different properties for semitransparent shadows. Each scene that’s created with Overcaster or any other script from Eki’s PlugPak could have been just as well made manually by the user. The scripts only automate the setup. LightWave calculates motion blur by rendering a different time step at each antialiasing pass and combining these to a single image. If the antialiasing setting is low and there’s fast motion in the frame, a series of ghost images can be seen. The spinning light trick uses this phenom- enon to multiply the apparent number of lights in the scene. When a high enough antialiasing setting is used, the shadows from the lights are blended together, giving the appearance of a single soft shadow. With a basic spinning light setup, the goal is to make the light rotate a full revolution, 360 degrees, during the antialiasing passes. LightWave’s default motion blur length is 50%, so to get 360 degrees of rotation the light has to turn 720 degrees each frame. When the user runs an Chapter 16 ······································ 200 Figure 16.5: Chastity model lit with Overcaster spot. Medium antialiasing with dithered motion blur. Overcaster script, the script first reads some parameters from the scene. The most impor - tant is the motion blur length of the current cam - era. If the user has set the motion blur to 5%, for example, the amount of spinning must be increased to 7200 degrees to get a full revolution during the antialiasing passes, as the desired 360 degrees is 5% of 7200. Overcaster automati- cally creates the spinners according to the current frames per second rate and motion blur amount. If the user changes these after applying Overcaster, nasty flickering errors may occur. To enable field rendering, Overcaster actually creates the spinning keyframes at frame 0.5, which causes both fields to get an equal amount of motion. However, with field rendering enabled, the Overcaster lights will by default rotate only half a circle. This phenomenon can be fixed by halving the motion blur length temporarily before applying the Overcaster lights when field rendering is used. Most Overcaster setups come in multiple resolutions. The Overcaster EZ rigs are the most basic form of spinning lights. The script adds the necessary spinner nulls with correct settings to a single light, and all the light’s properties are set up as if the light was a regular, non-spinning light. There’s usually only one slider control, for the soft - ness of the light. The normal resolution Overcaster setups are exactly the same as the EZ versions as far as the spinning light trick is con - cerned, but they incorporate the other Overcaster niceties, such as semitransparent, colored shadows. The dual and quad rigs multiply the number of lights, giving better results especially at lower antialiasing settings. The drawback is a hit in the render times. ·················· Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters 201 Figure 16.6: With high antialiasing and normal motion blur, a single spinning light will shine from 17 different positions. There’s no difference in render time compared to a regular light. [...]... Layout Figure 16.29 As a LightWave artist, you command LightWave to do things all the time You tell it to load an object, and you position the object and maybe rotate it You add a light and change the position, rotation, intensity, and color of that light You are executing a series of commands in LightWave But what if you are a lighting technical director with a series of favorite lighting techniques or... the commands you have executed since you started your LScript Commander session You can add any command or any sequence of commands from that list simply by selecting (or multiselecting) the command(s) and right-clicking That will copy the selected commands to the upper half Figure 16.30: LScript Commander Events tab Figure 16.31: LScript Commander Command Sequence tab The second tab, Command Sequence,... will alter the face of 3D, you can save the session and execute it from the LScript Commander interface whenever you want To be really cool, you can convert it into an LScript, give it a name like 3D Revolution,” stick it in your LScripts directory, and make it a button on your LightWave interface 2 18 · · · · · · · · · · · · · · · · · · Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters Creating... alphabetically lists all the commands you can use in an LScript so that you can manually add in whatever commands you like After you use LScript Commander for a while, you will start to understand the syntax and usage of many commands Who knows? Eventually you may become an LScript guru just by osmosis Once the commands are added, from either the Events tab or the Command Sequence tab, you can manually... your lighting setups in special scenes and then load the scenes, or you could create an LScript to recreate your special lighting setups The LScript Commander interface is simple and obvious The upper half of the LScript Commander interface is a simple text editor where you add all the commands you wish to use in your LScript In the lower half you have two resources from which you can draw commands... opened up the LScript Commander and pushed it to the side The purpose of having the Commander open is to make a recording of all the actions you take Once you have done everything you want to do, you can go back, look at the history list, and selectively copy commands into the text editor to make a nice, clean script Why select some commands and not others? Not all of the commands you execute will be... basement and come up with a dazzling new plug-in or LScript that will change the face of 3D On the other hand, if you are like most LightWave artists, you spent all your time learning your art and never bothered with programming Now there’s a solution for artists who want to automate procedures or techniques that they use often The solution is called LScript Commander What Is an LScript? An LScript is a LightWave. .. Go out door 216 · · · · · · · · · · · · · · · · · · Lighting Plug-ins, LScripts, Pixel Filters, and Image Filters Turn right Walk forward seven paces Turn left Enter kitchen Open cupboard Remove cereal Pour cereal into bowl } An LScript works just like this but commands LightWave to do things instead of commanding me LScript Commander LScript Commander is a Master Class plug-in found under the Scene... Layout, and assign the desired lighting properties to all the luxigon lights Perhaps one of the coolest lighting tools to come along in a while is luxigons I generally assign greatness by a ratio of power vs simplicity Luxigons are a perfect example of ridiculous simplicity with terrific power This tool was added to LightWave in version 7 .5 From instantly creating global lighting arrays to building lighting. .. light color to a light blue, then moved and rotated it into the position I wanted I then cloned that light, moved the clone to a new position and rotation, and changed its color to a light amber I then cloned that light, moved it to a new position and rotation, and changed its color to white After that, I turned on Low Antialiasing, turned off Adaptive Sampling, and hit F9 to render a sample frame After . do provide brief descriptions and example renders where I can. These tools can all be researched on the web at www.Flay.com and elsewhere, and in the LightWave manual and on the LightWave web site, www.newtek.com. It’s. Designer took 18 minutes and 18 seconds. Figure 16.2 is the same scene using an area light and ray tracing instead of Shadow Designer. While the final results are comparable, the LightWave- only. light and ray tracing in LightWave. (See color image.) G2 G2 from Worley Labs is a tool that will change your lighting process. With its interactive preview, you will be tweaking lighting and texture