G2 from Worley Labs is a powerful new collection of tools that is set to revolutionize many of the tasks we perform in LightWave every day. This tutorial will touch on some of the tools in G2 and how they relate to lighting design in LightWave
Sadly, this tutorial deals only with lighting design. That means we are going to touch on some of the lighting tools and a couple of the texturing tools. There are many more tools within G2 that fall beyond the scope of this article such as Subsurface Scattering, Art Mode, Photo Mapping and Skin Tools to mention only a few. There are even so many lighting tools that we will only be examining the basic ones here. So lets not waste any more space talking about what tools we wont look at and start talking about the ones we will. Remember, everything we do using G2 in this tutorial can be accomplished in LightWave without G2. The big advantage to G2 is that the work progresses so much more quickly and intuitively that we make much more productive use of our time.
Back in the days before G2 we used to design lights by starting with a script or scene analysis, sketching out our ideas using descriptions and scenic notes regarding time of day, setting, environment, light source and more aesthetic considerations such as the mood of the scene. We might make sketches of the scenic and lighting setup for a lighting TD. We would then either implement the design (or pass it to a lighting T.D. for implementation) then proceed with evaluation and adjustments (tweaking). At some point in the design process, when we felt we might be getting close to our lighting goal, we would hit the F9 key. We would wait for a single frame to render, evaluate the lighting make an adjustment (or a few adjustments) then hit the F9 key again, wait for another frame and so on. For complex scenes, these F9 renders could take quite a while. The artist spent a good deal of time not working on the lighting, waiting for the test render before moving on. Render-and-tweak, render-and-tweak.
Well, we still have to do script analyses. We still have to make decisions about the environment and mood of the scene. But as for the render-and-tweak method, things have changed. Now, with G2, F9-quality renders are nearly instantaneous. But the best part is G2 is so interactive that you can use the F9-quality preview window for real-time placement and adjustment of the lights themselves! No more guessing what its going to look like. No more waiting for long test frames to render. (well, OK, you have to wait for at least ONE test frame to render so LightWave can pass the data to G2). You can experiment so freely that the actual placement and light settings can be at the beginning of the design process in the concept phase instead of near the middle or end during the implementation phase. Imagine rendering a frame with default lighting, then adding more lights and working out their placements and settings live onscreen. Its almost like being on the stage and pointing the hot lights yourself!
Well enough of the preamble. Lets get a look at this baby.
The first thing well do is open a fresh Layout and add the G2 plugin in the usual way. After that, well want to edit our menu and add all the G2 plugins to our lighting menu.
Next, well load up a couple of objects. It doesnt matter what objects, were just going to fool around with some of G2s tools. Lets see, I have this funky dune buggy Ive been playing around with. Well put it on a ground plane. Lets use a nice bumpy desert.
The easiest way (and best way in my opinion) to add G2 to the object surfaces is to use the G2 Add to All plugin which is now conveniently located somewhere in your LightWave menus. Click that G2 Add to All button and the G2 surface shader will be added to every surface on every object in the scene. The most obvious advantage to this is that every surface will be visible and adjustable within the G2 preview. If you dont add the G2 shader to some surfaces you will not be able to adjust them in G2 and that would be very, very sad. On the other hand, you can add G2 only to specific surfaces if you really want to in the usual way within the Surface Editor. When you click the shader interface in LightWaves Surface Editor panel under the Shaders Sub-Tab, the G2:Surface panel will pop up. Well look at this panel shortly.
OK, now that we have added G2 to everything, lets check three settings.
Interactive Dynamic Update ensures that important information (like moving lights around in your scene) is passed to G2. Having Autokey on makes sure Lightwave records any positional or rotational changes you make to your lights, otherwise you have to make a keyframe every time you move or rotate a light.
Next Add a G2: Preview window by hitting the Add G2 Preview button on your G2 Layout menu.
You will probably want to turn on ray tracing in your render options too (or shadow mapping if youre using a shadow-mapped spotlight). Because you are designing a lighting setup for this scene, you need to see your shadows. G2 wont update the position of the shadows in the G2 preview, but will update surface illumination including light direction and position and specular highlights. If you change light positions and rotations a lot, youll want to do another F9 later to update the shadows.
Now that youre all set up hit the F9 key. Once the render is done, youll be able to see your render in the G2 preview window. Sometimes I like to keep the LightWave preview around minimized so I can see my starting point and compare it with the G2 changes Im making. Otherwise, the LightWave preview can be closed to save screen real estate and memory.
Thats all there is to getting G2 started. Now the real fun begins.
This render was done with default LightWave lighting. That means a distant
light at 100% and ambient intensity at 25%, both white.
Many artists will approach a lighting environment like this intending to use a standard (and very cliché) three-point lighting. That means the artists provides a key light from one side, a fill light from the other and a hot rim light from the top or back relative to the camera to add a specular highlight around the edges of the object. This artist gives very little thought to shadow types. Three-point lighting like this is what makes a lot of CG work look badly computer-generated. Three point lighting is a TV studio trick to make the news anchor stand out from the background. It has no place in a naturally lit exterior. After all, we are trying to create photo-real lighting, not studio lighting. Three-Point lighting also creates multiple hard shadows. I challenge anyone to go outside on this planet on a sunny day and demonstrate multiple shadows from a single sun.
In this image, the dune buggy object looks rather nicely lit, but there are too many shadows on the desert floor. This is a dead giveaway. Granted, it seems a very obvious example, but its more common a mistake than you might think. However many light sources you have, thats how many shadows you should have. In this case, there are exactly two light sources (not including radiosity), the sun and the sky. There should be a fairly hard shadow for the sun and a very soft shadow for the sky.
One of the keys to good lighting, whether using G2 or not, lies in understanding that the hardness (or sharpness) of a shadow is directly linked to the size of the light. Very tiny light sources like LEDs result in very hard-edged shadows while very large light sources such as the sky or a large fluorescent sign result in very soft-edged shadows. Think about this; All lights in the real world are area lights. Stew on that for a while. If you have it figured out, then youll know how to properly identify light sources.
Now, back to that first image we rendered. The first thing I notice in the render is that the default light is the wrong intensity and color for sunlight. I also notice that the shadows from the distant light are not quite right. Since I am using a ray-traced distant light for sunlight, I know that the shadows are hard-edged all the way around. This is not exactly how real sunlight shadows work, but the shadows lie close enough to the dune buggy for us to get away with it. If the shadows were very long, we would have to find a way to make our shadows soften with distance. There are a number of techniques for dealing with this, but wed prefer to use a distant light if we can get away with it because ray-traced distant lights render very quickly. So lets not worry about the fine details of this particular shadow. Instead well open up the Master Panel and have a look at improving the sunlights intensity.
The Master Panel provides us with tools for making global alterations to the scene. For direct control over individual surfaces, there is also a Surfaces Panel. We will look at Surfaces later.
One of the first things youll pick up about G2 is that there are usually a number of different ways to achieve a given effect. In this case, were going to look at four different methods of brightening our sunlight.
First, click Surface Boosts on the Master Panel. We know that when we light an object in LightWave, the light intensity is multiplied by the surface diffuse value. Therefore, if we increase the scenes global diffuse value, the overall scenic lighting intensity should increase. Lets try a Diffuse boost of 150%.
That looks a little better. Remember that when we boost a value to 150%, the boost value is multiplied by the original diffuse value of the surface, in this case 100%. If a surface has a diffuse value of 50%, for example, and you multiply it with a boost of 150%, the resultant diffuse value will be 50% X 150% = 75%. This holds true for all of G2s surface boosts in both the Master and Surface panels.
For a second method of brightening the sunlight, well reset our Diffuse surface boost to 100% (by clicking the reset button on the Surface Boosts page) and switch to the Image Process page which is the second button in the list on the left side of the G2 Master Panel.
On this page, there are two ways of adding simple brightness. You can increase the white gamma, which is sort of like increasing the image contrast. But for a more realistic intensity increase, crank the white Gamma Brightness up to 150%. Youll see a result identical to the diffuse boost method.
You can also achieve similar results in the Master Lighting page by increasing the Global Light Intensity, in other words, you just turn up every light in the scene. Or you can use the Light Groups page to assign any light or lights to a group and boost their intensity individually.
One of my favorite things about G2 that really speeds up lighting design is the ability to add, move rotate and change settings of lights in Layouts Light Properties panel. Most lighting values remain interactive in the G2 Preview. Say, for example, I dont like the direction of my sunlight. I simply select the light in Layout, move it, rotate it, change intensity or color and all those changes updates real-time in the preview.
You can see that the angle, color and intensity of the distant sunlight has changed. I made all the adjustments to my satisfaction in less than a minute. The shadow has not updated, of course, since ray-tracing needs to be recalculated, so well run a quick F9 right now to fix that.
Thats better. But now our imaginary director has come along and said the scene has changed to night-time. Normally, this would require a redesign and re-implementation of the lighting. Instead well adjust a few values in G2 and we will have our proverbial day-for-night shot. Lets look.
I just flipped through a few pages in the Master Panel and had the alteration finished in about a minute. Specifically, I made the following changes:
Surface Boosts: Diffuse: 50%
Distance Desaturation: 84.7%
This last setting, distance desaturation, is acting sort of like LightWaves fog in this shot. Its a simple tool. You set where you want it to begin (clip distance) and end (falloff distance). G2 desaturates the image over that range. Since fog often has the effect of color desaturation, this works quite well here. Its a subtle effect, but a worthy addition, since cold nights often have some amount of ground fog around.
Lets reset our scene and imagine we suddenly need to put the dune buggy on Mars instead. Also, this time well open up the surface panel first and deal with some object surfaces directly.
Since lighting design is about surface textures just as much as it is about lights, it is important to understand the relationship between surface textures and lighting in LightWave. The final pixel value you see is a computation of values from both light and texture settings. It is, therefore, appropriate to fiddle with a few of the surface tools in this tutorial.
OK, Mars. We know its much more orange than earth. Mars has orange skylight and orange sand. Lets look at the sand first. A very handy feature in G2 is the ability to select a surface just by clicking on it in the G2 preview. Ill click on the sand and now Im able to alter its values through the G2 interface.
All Ive done here is opened up the processing page of the Surfaces Panel and shifted the hue by -14.3 degrees and increased the color saturation to 140.7%. Color is often illustrated using a color wheel. The degrees shift is indicated by how many degrees from one color to the next you are shifting
That looks pretty good for the sand. But there are 137 surfaces on the dune buggy object. Id rather not go through each one and alter the surface parameters. So Im going to reset the desert color and make some global changes to the lighting. The first thing Im going to do is turn off LightWaves ambient intensity and add a large area light over the top of the dune buggy to act like a skylight. This is a cheap way of faking Global Illumination in Background Only mode. Granted, it takes a little time to render, but it takes less time than real G.I. This sky-light technique will also work well for our desert scene here on Earth, although, of course, the sky-light color on Earth will be blue, not orange. Lets do an F9 to update the new shadows from the new area light.
That took about four and a half minutes to render. In this side-by-side image you can see the LightWave preview on the left and the G2 on the right. The soft shadows beneath the buggy are starting to look good but we still need to make a few more changes.
There, thats more like Mars, in my imagination, anyway. I simply boosted my sky-fill area light to 50%, turned ambient off, adjusted my Red Gamma to 1.396 and dropped the global light intensity to 90%. These are all subtle changes and I just paged through the Master Panel until I had it looking the way I like.
You will find after using G2 for a few hours that youll really start to get fluent with the controls and adjustments. You will quickly discover how fun and easy it is to make changes that were previously tedious and time-consuming.
I have only touched on a few of G2s tools in this tutorial. There are many more tools in there, each just as easy to grasp and use. If you think of G2 not as a single tool but as an artisans toolkit then you will realize that you can learn the tools one at a time as you need them and that each tool is essentially pretty simple to use.
Ive decided to stick our dune buggy back on earth and throw in that nice large area light for a blue sky fill. Area light shadows are so beautiful! Im going to go and play with G2 for a while, maybe add a little HV sand for the fun of it Ill let you know what I come up with
Nicholas Boughen spent most of his career as a scenic and lighting designer for the stage. In the mid 1990s he started using 3D applications to previsualize his scenic and lighting designs. As a Lighting Designer, Boughen has found new freedoms with LightWave and is now able to create CG lighting that was impractical or technically impossible on the stage. Boughen is in the final stages of writing the book LightWave 3D 7.5 Lighting due to be published in April 2003, ISBN 1-55622-354-4.