{1} 3DSMAX light distribution principle and matters needing attention

{2} max5 radiosity workflow

{3} 3DSMAX lighting considerations

{4} 3dsmax Lighting Technology Foundation

{5} Overview of main light setting effect in 3ds Max

{6} Example of standard lighting

{1} 3DSMAX light distribution principle and turning points for attention.

The process of setting lights is simply called "lighting". Although a complex scene is illuminated by 100 lighting technicians, there will be 100 different schemes and effects, but everyone will abide by several principles of lighting. For indoor renderings and indoor photography, there is a famous and classic lighting theory, which is "three-point lighting". The author briefly describes here:

Three-point lighting, also known as area lighting, is generally used for small-scale scene lighting. If the scene is large, it can be divided into several smaller areas for lighting. Generally, three light zones can be used, including main light, auxiliary light and background light.

Main light: it is usually used to illuminate the main object and its surrounding area in the scene and play the role of projecting the main object. The main relationship between light and shade is determined by the main light, including the direction of projection. The task of the main lamp can also be completed with several lamps as needed. If the main light is in the position of 1.5 degrees to 30 degrees, it is said to be smooth; At the position of 45 degrees to 90 degrees, it is called sidelight; It becomes a side backlight at the position of 90 degrees to 120 degrees. The main light is usually made of spotlights. I like to set the brightness of the main light around 2 40.

Auxiliary light: also known as auxiliary light. The fan-shaped reflector is illuminated by spotlight to form a uniform and indirect soft light source, which can fill the shadow area and scene area missed by the main light, reconcile the contrast between light and dark areas, and form a sense of depth of field and layering. In addition, this wide and uniform light distribution makes it lay the background color for the scene and define the tone of the scene. In order to achieve the effect of soft lighting, the brightness of auxiliary light is usually only 5 0%-80% of that of main light.

Background light: its function is to increase the brightness of the background, thus setting off the subject and separating the subject and object from the background. Generally, floodlights are used, and the brightness should be dark but not too bright.

The following figure is a simple schematic diagram of the lighting settings in this area.

The light distribution sequence is: 1) First, determine the position and intensity of the main light; 2) determining the intensity and angle of the auxiliary light; 3) Equipped with background lights and decorative lights. The light distribution effect produced in this way should be clear in priority and complement each other.

There are several places that need special attention when lighting:

1) The lighting should be exquisite but not excessive. Too many lights make the work process messy and difficult to handle, and the display and rendering speed will also be seriously affected. Only the necessary lights can be kept. In addition, we should pay attention to the use of light projection, shadow mapping and material mapping, and it is best to use mapping where light can be replaced by mapping. For example, it is much more convenient and effective to show the light in the window when you look at it from the outside at night than to simulate it with lights. Don't distribute light casually, otherwise the success rate will be very low. For unnecessary lights, we must resolutely not keep them.

2) The lighting should reflect the light and shade distribution of the scene, and it should be hierarchical, and all lighting should not be treated equally. Choose different kinds of lights as needed, such as spotlights or floodlights; Decide whether to project the density of light and shadow as needed; Determine the brightness and contrast of the light as needed. If we want to achieve a more realistic effect, we must make some efforts in light attenuation. You can temporarily turn off some lights to eliminate interference and set other lights better.

3) You should know that the lights in max can be surreal. We should learn to use the "exclusion" and "inclusion" functions of light to see whether absolute lighting can illuminate or project an object. For example, in order to simulate the lighting and projection effect of candlelight, we usually place a floodlight at the wick of the candle. If this lamp doesn't project the candle body, the big shadow produced by the candle body on the desktop may give us a headache for half a day. In architectural renderings, the method of "exclusion" is often used to make lights not produce lighting or projection effects on some objects.

4) Lighting should follow the process from theme to part and from simple to complex. For the formation of lighting effect, we should first adjust the angle to set the main style, and then adjust the characteristics of lighting attenuation to enhance the sense of reality. Finally, adjust the color of the light and change the details. If you really want to simulate the effect of natural light, you must also have a deep understanding of natural light sources. Reading more books and doing more experiments will help. The lighting used in different occasions is also different. In the production of indoor renderings, in order to show a gorgeous effect, some main lights are often set to light orange, which can achieve the effect that materials are not easy to achieve.

In short, it is only a matter of time before you practice more and dare to practice and master the essence of running out of light.

{2} max5 radiosity workflow

Physical-based workflow

When using radiosity to simulate a real lighting scene, please pay attention to the following points:

* Scene size: Make sure your scene has the correct size and consistent units (the lighting in a room with a height of 120m is very different from that in a room with a height of 120cm).

* Lighting: You must use photometric lights and ensure that the brightness of these lights is within the correct range.

* Natural light: To simulate natural light, please make sure to use IES Sun and IES Sky. They can give the correct lighting information according to the specific location, date and time.

* Material reflectivity: You must ensure that the reflectivity value of the secondary material in the scene is consistent with the reality. For example, the reflectivity of a wall with white paint is about 80%; However, the reflectivity of pure white material (RGB: 255,255,255) is 100%. In this case, you must manually adjust the reflectivity.

* exposure control: exposure control is equivalent to the aperture of the camera. You can use it to control the final rendering result and optimize the rendered image.

Physics-based radiosity workflow using photo photometric lighting;

* Check and adjust the size of objects in the scene to match their physical size, and adjust the reflectivity of materials to match their physical properties.

* Put photometric lights into the scene. You can place virtual lights just like the real world places lights. For relevant information, please refer to the light brightness table attached to the help.

* Select the Rendering Menu Environment dialog box. Select the exposure type you want to use.

* Render the scene to preview the lighting effect. In this step, the light energy transfer is not handled, but you can quickly determine the position and intensity of the direct light and adjust the position and intensity of the direct light.

* Select the Rendering Menu Advanced Lighting dialog box. Select radiosity in the advanced lighting options. (Make sure that the small box in front of Active is checked)

* In the Radiosity Parameters rollout, click Start to calculate radiosity. After calculation, you can see the effect in the view. The lighting effect is displayed directly on the geometry, so the adjustment can be easily observed in the view without recalculation.

* Click to render the scene again. The renderer calculates direct light and shadows to complete the rendering work.

Based on physical properties, you can create a scene without using lights, but you must pay attention to the following points:

Lighting: Because the calculation of light energy transfer is based on physical properties, standard lighting is interpreted as photometric lighting in the calculation. For example, a spotlight with a multiplier of1.0 will be converted into a light with a brightness of 1500 candle. The light attenuation of standard lighting, no matter how you set it, will be carried out according to the internal algorithm of light energy transfer, regardless of your setting.

Natural lighting: If you don't want to use physics-based lighting types to simulate natural light, you can use direct light to simulate sunlight and skylight to simulate skylight.

Exposure control: Because standard lighting is not based on precise physics, you only need to adjust the result of light energy transfer without affecting direct lighting. Using logarithmic exposure control, only turning on the indirect lighting function can control the result of light transmission by using the brightness contrast function of exposure control.

Radiometric workflow of standard lighting:

* Make sure that the size of the geometry in the scene conforms to the actual size.

* Place standard lights in the scene.

* Render scene preview lights. In this step, the light energy transfer is not handled, but you can quickly determine the position and intensity of the direct light and adjust the position and intensity of the direct light.

* Select the Rendering Menu Advanced Lighting dialog box. Select radiosity in the advanced lighting options. (Make sure that the small box in front of Active is checked)

* In the Radiosity Parameters rollout, click Start to calculate radiosity. After calculation, you can see the effect in the view. The lighting effect is displayed directly on the geometry, so the adjustment can be easily observed in the view without recalculation.

* Select the Rendering Menu Environment dialog box. Select the exposure type you want to use.

* When using standard light in optical energy transmission, please ensure that logarithmic exposure control is used and only the correct direct exposure is selected. This makes the exposure control only affect the effect of light energy transfer. In this way, you can use brightness and contrast control to adjust the indirect light effect without affecting the direct light, so that the light energy transfer effect can be controlled in the correct range.

* Click to render the scene again. The renderer calculates direct light and shadows to complete the rendering work.

By default, radiosity calculates the current frame. If there are animated objects in the scene, or you need to transmit light to calculate each frame of the animation, please select the option of Calculate Radioactivity in the Render Scene dialog box.

In the process of animation calculation, when the object moves or the light changes, it is necessary to recalculate the ray tracing calculation in each frame. If there is no change between two frames, the rendering engine will not perform radiosity calculation.

Keep in mind that flicker may occur between animation frames because the rendering engine uses random statistical sampling.

Tip: Before radiosity calculates a long animation, you should manually calculate a frame and ensure that the final effect is correct.

Tip: If your animation is just camera motion (such as an architectural tour effect map), you don't need to calculate the light energy transfer every frame, you just need to calculate one frame.

According to the table below, you will get better results.

Workflow based on physical attributes Workflow based on non-physical attributes

Photogrammetry photometric light standard light

Daylight IES sun and IES sky parallel light and texture sky

Exposure controls any logarithm to turn on the correct direct unique option.

unit

Determine the size of the geometry in the scene Determine the size of the geometry in the scene.

Fit to the real size, fit to the real size.

{3} The lighting principle of 3ds Max and the order of lighting attention points are as follows:

1) first determine the position and intensity of the main light;

2) determining the intensity and angle of the auxiliary light;

3) Equipped with background lights and decorative lights. The light distribution effect produced in this way should be clear in priority and complement each other.

There are several places that need special attention when lighting:

1) The lighting should be exquisite but not excessive. Too many lights make the work process messy and difficult to handle, and the display and rendering speed will also be seriously affected. Only the necessary lights can be kept. In addition, we should pay attention to the use of light projection, shadow mapping and material mapping, and it is best to use mapping where light can be replaced by mapping. For example, it is much more convenient and effective to show the light in the window when you look at it from the outside at night than to simulate it with lights. Don't distribute light casually, otherwise the success rate will be very low. For unnecessary lights, we must resolutely not keep them.

2) The lighting should reflect the light and shade distribution of the scene, and it should be hierarchical, and all lighting should not be treated equally. Choose different kinds of lights as needed, such as spotlights or floodlights; Decide whether to project the density of light and shadow as needed; Determine the brightness and contrast of the light as needed. If we want to achieve a more realistic effect, we must make some efforts in light attenuation. Some lights can be temporarily turned off to eliminate interference, and other lights can be set better.

3) You should know that the lights in MAX can be surreal. We should learn to use the "exclusion" and "inclusion" functions of light to see whether absolute lighting can illuminate or project an object. For example, in order to simulate the lighting and projection effect of candlelight, we usually place a floodlight at the wick of the candle. If this lamp doesn't project the candle body, the big shadow produced by the candle body on the desktop may give us a headache for half a day. In architectural renderings, the method of "exclusion" is often used to make lights not produce lighting or projection effects on some objects.

4) Lighting should follow the process from theme to part and from simple to complex. For the formation of lighting effect, we should first adjust the angle to set the main style, and then adjust the characteristics of lighting attenuation to enhance the sense of reality. Finally, adjust the color of the light and change the details. In order to simulate the effect of natural light realistically, we must have a deep understanding of natural light sources. Reading more books and doing more experiments will help. The lighting used in different occasions is also different. In the production of indoor renderings, in order to show a gorgeous effect, some main lights are often set to light orange, which can achieve the effect that materials are not easy to achieve.

In short, it's only a matter of time before you practice more and dare to practice and master the essence of running out.

Illumination is the most important means to simulate natural lighting effects in 3DS MAX, and it can be called the soul of MAX scene. However, complicated lighting settings and changeable application effects are a big problem that puzzles many novices. How to obtain satisfactory lighting effect makes many friends feel headache and helpless. The main purpose of this tutorial is to lead you to deeply understand the lighting settings in 3DS MAX, completely dispel the confusion of friends, and thus create a more realistic and desirable MAX scene.

I. Overview of MAX Scene Lighting

To understand the lighting technology of MAX, we must first understand the working principle of lighting in MAX. In MAX, in order to improve the rendering speed, the light is not radiated. This is because the calculation speed of light transmitted by light energy is very slow. Friends who have never felt it will understand the calculation speed of light tracing materials. In other words, the working principle of light in MAX is different from that in nature. If you want to simulate the special properties of nature, such as light reflection (such as water reflection effect), diffuse reflection, radiation, light energy transmission, light transmission effect, etc., you must use various means (not only lighting means, but also materials such as light tracing materials. ) to simulate. Some people complain why KINITEX company doesn't use similar LIGHTSCAPE software to simulate similar natural lighting system. The reason is not that KINITEX does not master this technology, but that MAX's main task is animation. As we all know, the lighting operation speed in LIGHTSCAPE is very slow, and it often takes a long time to render a picture (so this software is positioned for photo-level still picture rendering). In animation, one-second animation needs to render more than 20 pictures (NTSC 30 frames/second, PAL 25 frames/second, movie 24 frames/second, smooth motion at least 15 frames/second), and one minute needs to render more than 1000 pictures, so your waiting will be endless. Fortunately, there are many plug-ins developed by third parties in MAX, among which the light transmission and MENTAL RAY (large plug-ins of "lighting effect+special hidden weapon+high quality rendering") are excellent and can be selected by users. However, the operation speed is a bit unsatisfactory. Of course, if you just render a static picture instead of animation (such as architectural renderings, etc. ), in order to get better results and more convenient lighting settings, it is ok to wait for an hour. The biggest advantage of lighting in MAX is the calculation speed, and the lighting quality is actually good. As long as it is set properly, it can also produce authentic lighting effects.

In MAX, not all lighting effects are accomplished by lighting. For the light source, it may also be the simulation of materials, post-video special effects and even atmospheric environment. It is probably the most suitable to simulate the luminous effect of firefly tail with self-luminous material, and it is also good to simulate the luminous effect of tail with combustion device in atmospheric environment when rocket is launched, but it is a good idea to simulate the neon effect at night with the luminous stunt in video post-processing. As the messenger in MAX's three-dimensional scene, lighting is the most important means for MAX to show the lighting effect. As a special object in MAX, lighting often does not simulate natural light sources. Spying? What's the trick? As a special object, the light in the T-shaped building is invisible, but the lighting effect is visible. If there are no lights in the scene (including hidden lights), then all objects are invisible. However, there are two default lights in the MAX scene, which are generally invisible, but still play a role in illuminating the scene. Once a new light source is created in the scene, the default light will be automatically turned off. If the lighting position and brightness in the scene are not ideal at this time, it will not catch up with the effect of the default lighting. If all the lights in the scene are deleted, the default lights will be turned on automatically. One of the default lights is located in the upper left corner of the scene and the other is located in the lower right corner of the scene.

There are five basic types of lights in MAX, which are OMNI, target spotlight, free spotlight, target direct and free direct. In addition, under the system in the creation panel, there is also a daylight lighting system, which is actually a variant of parallel light, and generally simulates sunlight when making outdoor architectural renderings. There is actually an "ambient light" (which can be set in the "Rendering/Environment Settings" dialog box). Ambient light has no direction and no light source, and is generally used to simulate the diffuse reflection of light. Ambient light should not be too bright, otherwise it will dilute the scene, causing the contrast to go up and make the scene eclipsed. Experienced people usually set the brightness value of ambient light to 0 first, and then set other lights for fine-tuning, which can often achieve better lighting effect.

By default, the lights in MAX are not projected, but they can be set to be projected or not. The quality, intensity and even color of shadows can be adjusted. If you want to correctly represent the shadow of a transparent or translucent object, please use the ray tracing shadow method. In the absence of projection, the light in MAX is penetrating, and the light on the fifth floor of a building can illuminate the first floor even if it is blocked by the floor. Interestingly, if the value of the "multiplier" of light is set to a negative number, it can also produce the effect of absorbing light or negative light, and it can produce the complementary color effect of a certain color (black represents white). In indoor architectural renderings, it is usually used to simulate the phenomenon of uneven light distribution, or artificially "blacken" the surface of bright objects. If you dynamically change the brightness of the light and the value of the multiplier, you can even simulate the instantaneous lighting effect of lightning. Another important function of lighting in MAX is that you can specify which objects (lighting and projection) lighting will affect or not through the "exclusion" function, so as to optimize the rendering speed or create special effects, which learners must not ignore.

Please remember two lighting principles in MAX. First, the farther away the light is from the object, the greater the illumination range, and vice versa. For an object, the smaller the angle between light and its surface (actually the incident angle), the darker its surface appears; The larger the included angle, the brighter the surface. This is similar to the relationship between sunlight and the ground. If the light is far away from a plane (such as the ground) and shines at right angles to this plane, the lighting effect is very uniform. However, if the same light is put too close, a "light pool" (light gathering area) will be produced, because the angle of light contacting the surface will change greatly. If you want a lamp to illuminate as many objects as possible, please widen the distance between the object and the lamp. In order to make the light shine brightly on the surface of the object, the angle between the light and the surface of the object should be adjusted to be larger. Many friends have difficulty in creating lights. It doesn't matter if you don't build your own lighting effect. Once you set up your own lighting, you will find that all the objects in the scene are dim. This is the reason why the distance and included angle between the light and the object are not set well. Many friends don't know the secret. See a light is not bright enough, build another one to see. In this way, after more than 10 lights are built, the lights in simple scenes are even more strange. In fact, MAX's scene lighting theory is very similar to photographic lighting in reality. For small areas, the so-called "three-point lighting" (main light+backlight+auxiliary light) can be used to solve the lighting problem. For large scenes, such as the interior renderings of the auditorium, the large scene can be divided into smaller areas and the lighting problem can be solved by the method of "three-point lighting". Of course, flexible handling of different situations can sometimes produce dramatic results. Also remember, don't try to create or move lights in transparent pictures or cameras.

In MAX, lights have attenuation properties, but by default, lights are not attenuated. In order to better simulate the reality (the light in the real world is attenuated, that is, the farther the distance, the smaller the brightness until it finally disappears), it is usually necessary to manually turn on the attenuation attribute of light. On the one hand, you can specify the influence range of lighting, on the other hand, the lighting effect created is very realistic. For floodlights, attenuation only affects the lighting distance; For spotlight or directional light, you can specify not only how far the light can shine, but also the attenuation effect of the aperture edge.

The default light has no color. By changing the color of light, various lighting effects can be simulated. For example, to simulate colored lights or sunlight at sunrise, you should adjust the color of the lights. In addition, lighting combined with environmental special effects can produce special effects. For example, using volume light in the environment can simulate the effect of stage spotlight, and using floodlight with glow in special effects can simulate the sun shining on the earth. With FOG effect, you can even make the projection effect of light passing through fog.

{4} 3dsmax Lighting Technology Foundation [repost]

Fundamentals of 3dsmax Lighting Technology

You may rarely consider how light sources work in the real world. However, when you create lights in the computer graphics world, you usually spend a lot of energy and try to achieve the desired effect. Three-dimensional software can create free PPP of any kind of lighting at will, which sometimes makes it difficult for you to create a realistic appearance in exquisite images. When it is difficult for you to achieve lighting effects in a specific scene, it is usually helpful to know some traditional lighting basics.

□ When you are ready to light up a scene, you should pay attention to the following questions:

-What was the scene like?

Scene lighting is usually divided into three types: natural light, artificial light and their combinations.

The natural light representing PPP is sunlight. When using natural light, there are several other questions to consider: what time of day is it now; Is it clear or cloudy in Wan Li? Besides, how much light is reflected in the environment?

Artificial light can be in almost any form. Any environment illuminated by electric lights, fire or both can be considered man-made. Artificial light is probably the most common of the three light sources. You also need to consider where the light comes from and its quality. If there are several light sources, which one is the main light source? It is also important to determine whether to use colored light. Almost all light sources are colored, not pure white.

The last kind of lighting is a combination of natural light and artificial light. When shooting PPP outdoors in bright light, photographers and lighting engineers sometimes use mirrors or auxiliary lights to alleviate harsh shadows.

-What is the purpose of lighting?

In other words, what is the tone and atmosphere of the scene? It is very important to express a hue in light for the appearance of the whole image. In some cases, the only goal is to see one or several objects clearly, but this is usually not the case, and the actual goal is quite complicated.

Lighting helps to express an emotion or guide the audience's eyes to a specific position. It can provide more depth for the scene and display rich layers. So, when creating lights for a scene, you can ask yourself, what is the keynote to express? Did the lighting you set enhance the story?

Are there any special lighting effects in the scene? If so, should it be created by lighting or other means?

In addition to the usual lighting types, many 3D animation softwares also provide many special effects, such as incandescent lamps, stereoscopic light sources and special materials belonging to PPP. Although strictly speaking, some are not light types, they are usually added to the appearance of visible light effects in scenes. A simple example is the flicker or luminescence of a visible light source. Since these effects cannot be generated automatically in 3D, you need to include them in the rendering and consider their appearance and advantages.

-Did you mention the source of creativity?

When creating realistic scenes, we should get into the habit of drawing materials from actual photos and PPP. Good reference materials can provide you with some clues to know what specific objects and environments look like at different times of the day or under specific conditions.

By carefully analyzing the positions of highlights and shadows in a photo, it is usually possible to reconstruct the basic position and intensity of light that affects the image. You can also learn a lot by using the existing original materials to reconstruct the lighting layout.

-After considering the above problems, it's time to press your lips for Huanyan and forgive him for playing neon? Jun [6] travel bald and closed? However, there are three basic types of light sources: key light, auxiliary light and background light, which work together harmoniously.

-Key light

In a scene, its main light source is usually called the main light. The key light is not necessarily just the light source, but it must be the main light source for lighting. Similarly, a highlight light may not be fixed in one place like a point light source.

Although the point light source is usually placed at three-quarters of the position (rotated 45 degrees from the front of the object and 45 degrees upward from the center line, which is often used as a fixed position), it can also come from below or behind the object or any other position according to the needs of specific scenes. The main light is usually the first light placed to create a preliminary lighting effect in the scene.

Although the initial placement provides a good way to illuminate the object, the result is indeed a monotonous image. Shadows are usually rough and obvious. Similarly, the scene always looks too dark, because there is no natural ambient light to highlight the shadow area. This situation is very useful in some scenes, such as night scenes, but it is somewhat inappropriate for most pictures.

-Auxiliary light

Supplementary light is used to fill the dark and shadow areas of the scene. The main light is the most eye-catching light source in the scene, but the auxiliary light can provide depth of field and realism.

The more important supplementary light comes from natural diffuse reflection, which is usually called ambient light. This type of light is important in part because it improves the brightness of the whole scene. Unfortunately, the ambient light of most renderers is evenly applied to the whole scene. It reduces the overall darkness of the scene, eliminates some possible special PPP, and cannot model any light and shadow on the illuminated object, which is the main reason why the scene looks unreal.

A better way to simulate ambient light is to place low-intensity spotlights or floodlights in a reasonable position in the scene. This kind of auxiliary light should reduce the shadow area and add some light to the lower side and the corner where the key light can't be directed directly.

In addition to the natural scattered light or ambient light in the scene, supplementary light is used to illuminate areas that are too dark or to emphasize certain parts of the scene. They can be placed opposite the main light to soften the shadows.

-Backlight

Background light is usually used as "edge light" to separate the target object from the background by illuminating the edge of the object. It is often placed in the position facing three-quarters of the bond light and acts on the edge of the object, resulting in a small reflective highlight area. If the model in a 3D scene consists of many small round edges, this highlight can increase the believable PPP of the scene.

-Other types of light sources

The actual light sources are those that actually appear in the scene. Table lamps, car headlights, lightning and flames burning in the wild are all potential light sources.

□ After setting the lighting for the scene, there are some other factors to consider.

Is my solution simple and necessary?

The lighting in the scene is different from the real lighting, so more efforts need to be made in rendering time. The more complex the lighting settings, the longer the rendering time and the more difficult the lighting management will become. You should ask yourself whether every kind of lighting is necessary for the image you create.

Adding a light source will naturally reduce the number of reflection points. In some cases, adding light sources will not improve the appearance of the scene, and it is difficult to distinguish the value of added light sources. You can try to view each light source individually to measure its relative value to the scene. If there is any doubt about its function, delete it.

-Do some objects need to be excluded from the light source?

When rendering, excluding objects from some light sources can save time.

This principle is also correct for making shadows. Every lamp in the scene