3ds max Lighting phần 4 pps

Once the Daylight System is added to your scene, you will see a param - eters rollout that allows you to select the precise location you desire as well as the precise date and time of day. Unfortunately, if you don’t live in the United States, your city will not be listed in the Get Location list. The Daylight System’s purpose is to provide physically accurate daylight models depending on your location on the globe and the time of day. This would likely be very useful if you were creating forensic anima - tions. If you’re an artist working in games or visual effects, though, you probably won’t have much use for the Daylight System. For further details on how to set up and use the Daylight System, please see the manual. Photometric Light Parameters For details on photometric light parameters, please refer to Chapter 12, “General Light Parameters,” where they are covered in detail. ··································· Photometric Lights 113 Figure 9.13: Control Parameters rollout for the Daylight System Photometric Light Presets Here’s one particularly cool feature of photometric lights. There are a number of built-in light type presets. Say, for example, you want a 60-watt lightbulb, a halogen lamp, or a streetlight. You can fiddle around and try to find the right settings or, from the Create>Lights>Photomet - ric Lights>Presets menu, you can simply locate your preset, and bing! It’s in the scene. Different light types come with different icons. All the settings are changeable in the Modify panel. Exposure Control (Environment Control) Exposure control can be accessed through the Environment and Effects panel. This tool allows you to process the exposure of your image, just as though you were opening or closing the aperture on a camera. When using standard lights, you will probably not use this tool very often; however, when using photometric lights, the light energy calculations can be a little unpredictable and you may find the exposure control set - tings to be quite useful. Chapter 9 ······································· 114 Figure 9.14 There are a lot of details in the MAX documentation about how to use this tool, but it’s really quite easy to pick up if you just fiddle with it for a minute. Keep in mind, though, that exposure control doesn’t have any effect over radiosity, so be sure you set your exposure before enabling radiosity in your scene. By now, you should have a basic understanding of the photometric light - ing tools available in MAX. In Part III of the book, we’ll be putting most of these tools through their paces to see what can be done with them. ··································· Photometric Lights 115 Figure 9.15: The Environment and Effects panel Chapter 10 Other Lighting in MAX In addition to standard lights, mental ray lights, and photometric lights, 3ds max is equipped with other lighting tools that help us create physical lighting effects like radiosity and caustics, atmospheric effects like volu- metrics, lens flares, and even materials that emit light energy. Light Tracer and Radiosity (Default Scanline Renderer) Radiosity, also known as Global Illumination in MAX, can be handled in a couple of different ways. Both Light Tracer and Radiosity can be found in the Advanced Lighting tab of the Default Scanline Renderer panel. 116 Figure 10.1: The Default Scanline Renderer panel Advanced Lighting tab The first solution is called Light Tracer. Light Tracer is not a physically accurate radiosity model, but it does pro- vide light bounces and color bleed that simulates radiosity and will often be sufficient. ································· Other Lighting in MAX 117 Figure 10.2: Light Tracer options Figure 10.3: Radiosity options Radiosity, on the other hand, provides a physically accurate model and includes some special tools and settings not available with Light Tracer. For a detailed discussion of both Radiosity and Light Tracer, please refer to Chapter 14. Caustics Caustics in MAX come in two flavors: reflected and refracted. When we use the word “caustics,” we are referring to the redirec - tion of light into a more dense and intensified beam, usually focused on a nearby surface. For example, when light shines through a glass of wine, you see an intensified area of light on the table opposite the light. This is because the glass and its liquid contents are acting like a lens and are refracting and focusing the light. A shiny ball bearing can also result in a caustic lighting effect. While a ball bearing is opaque and will not let light pass through, it is very shiny and reflective; therefore the light will reflect off the shiny surface and onto nearby surfaces. Because the ball bearing is spherical, its surface acts like a focusing mirror, causing the reflected light to intensify on nearby surfaces. A gold ring will also act like this. The interior face of the ring acts like a focusing mirror, also making a caustic reflection appear on nearby surfaces. MAX is capable of both types of caustic effects when using the men- tal ray rendering engine. But the fact is that caustics are rarely, if ever, used in actual production. I’m not going to dedicate space to this lighting effect, but complete tutorials and tool descriptions are available in the MAX documentation. Volume Lights Volume lights simulate particles in the atmosphere. Take a smoky bar, for example. If you are in a smoky bar and the bright stage spotlights come on, you will “see” the smoke in the light beams. In fact, the smoke is everywhere in the room, not just in the light beams. However, to save on rendering time, it is more efficient to only render the smoke where the light beam is located. This is what is meant by a “volume light.” It is a light that includes particulate density or volume within the light beam, without calculating that particulate density in the rest of the environ - ment. Quite clever, if you think about it. Volume lights work with all light types in MAX, including mental ray lights. They are extremely easy to add to your scene. Chapter 10 ······································ 118 To demonstrate, simply add a light, such as a spotlight. I’m going to add a spotlight, a direct light, and an omni light to show the different volumetric effects. In Figure 10.4, you can see the spotlight cone and volumetric shape. This shows where the volumetric effect will render. Note: Different light types will provide differently shaped volumet - rics. For example, the spotlight will create a cone-shaped volumetric, the omni light will create a sphere-shaped volumetric, and a distant light will create a cylinder-shaped volumetric. Open the Atmospheres & Effects rollout on the Light Modify panel. ································· Other Lighting in MAX 119 Figure 10.4 Figure 10.5 Click the Add button. Click on Volume Light and click OK. Now set the near and far attenuation options for each of the lights and render a frame to have a look. Chapter 10 ······································ 120 Figure 10.6 Figure 10.7 The volumetric will adhere to the shape of the light volume, even if it is occluded by geometry, taking on the shape of the shadows. Volume lights can be extremely helpful for creating car headlights, jet blasts, flashlight beams, lasers, and, you guessed it, spotlights in smoky bars. Objects as Lights One of the greatest single uses for radiosity is the ability to use the Advanced Lighting Override material to make self-illuminated objects emit light into the scene. This allows us to build custom lights of any size and shape. If, for example, you need a frosted lightbulb or a neon sign, this is a perfect solution for correctly and beautifully illuminating your scene. Making a self-illuminating object is incredible simple. First, click on the Standard button next to the material name in the Material Editor. ································· Other Lighting in MAX 121 Figure 10.8 This will open up the Material/Map Browser. Chapter 10 ······································ 122 Figure 10.9: The Material Editor Figure 10.10: The Material/Map Browser [...]... rollout Figure 10. 14: The Render Scene panel With Radiosity active, click the Start button on the Radiosity Processing Parameters rollout This will let MAX calculate the lighting solution for the luminous material Once the calculation is finished, render a frame and enjoy your luminous object! 1 24 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Other Lighting in MAX Figure 10.15: A... Other Lighting in MAX Click on Advanced Lighting Override and click OK Figure 10.11 You will get a dialog asking whether you want to discard the existing material or keep it as a sub-material If you want to build a new material, click the discard option If you already have a material that you like but you just want to make it luminous, keep the old material and click OK Now, you will see the Advanced Lighting. .. · · · · · · · · · · · · · · · · · · · · · · · · Figure 10.23: Multi-selecting lens effects parameters Figure 10. 24 shows a render with an omni light that has all the lens effects active 130 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Other Lighting in MAX Figure 10. 24: An omni light with every lens effect That’s a lot of effects, and is definitely over the top, but fun to try out... Advanced Lighting Override Material rollout 123 Chapter 10 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · In the Special Effects section, turn the Luminance Scale up to 1000 Figure 10.13 Now, in the Render Scene panel, make sure you have the Default Scanline Renderer selected, and add the Radiosity plug-in in the Advanced Lighting tab under the Select Advanced Lighting. .. · · · · · · · · · · · · · · · · · · · · · · · Other Lighting in MAX My last bit 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 have a basic understanding of the use and purpose of lens effects, volume lights, objects as lights, and basic radiosity in MAX Remember, it is usually the creative and uncommon... artist 133 Chapter 11 Manipulating Lights This chapter will help springboard new artists and artists inexperienced with MAX into a complete understanding of how to add and manipulate lighting instruments By the time you have finished this chapter, you should know how to create all MAX light types and position them so they will illuminate your scene just the way you’d like This chapter deals mainly with... entire item larger or smaller 140 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Manipulating Lights Figure 11. 14 If, on the other hand, you select one of the outer rectangular shapes on the gizmo, the item will stretch along that plane and stay unchanged in the other planes Figure 11.15: Selecting and dragging the X-Z scale plane squashes the light cone 141 Chapter 11 · · · · · ·... floodlights, etc., have a hotspot Although light designers go to a great deal of trouble to remove hotspots from lighting instruments, they still exist and can serve to add a sense of realism to a light source 145 Chapter 11 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Figure 11. 24 When you adjust the hotspot, you will see a separate light cone or cylinder within the cone angle This... Effects tab When you click on the Lens Effects entry in the Effects list, all the appropriate rollouts will appear below 128 · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · Other Lighting in MAX Figure 10.21: The Environment and Effects panel Figure 10.22: The Lens Effects rollouts You can start adding lens effects in the Lens Effects Parameters rollout If you decide to add all of them,... chapter deals mainly with creating and moving lights For instruction on how to change light settings and properties, please see Chapter 12, “General Light Parameters.” Creating Lights All lights in 3ds max are created from the Command Panel’s Create tab You simply click the Light icon, choose between Standard and Photometric lights in the drop-down, click on the light type you wish to create, and then . panel Chapter 10 Other Lighting in MAX In addition to standard lights, mental ray lights, and photometric lights, 3ds max is equipped with other lighting tools that help us create physical lighting effects. see the Advanced Lighting Override Material rollout in the Material Editor. ································· Other Lighting in MAX 123 Figure 10.11 Figure 10.12: The Advanced Lighting Override. the Advanced Lighting tab under the Select Advanced Lighting rollout. With Radiosity active, click the Start button on the Radiosity Processing Parameters rollout. This will let MAX calculate the lighting