"Dry Goods" Wu Xingyu: 1 hour to master the theoretical knowledge of effect drawing lighting

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The content of this article is organized from the design headline open class

This dry article is about 10,000 words, and you can read it in about 10 minutes.

micro lecture recording

Guest of this issue

Wu Xingyu

Screen Name: Glass Transparent Man

Interior designer and renderer, ant beak organizer, his works have been selected for VwaArtClub (predecessor of VRayWorld) and cover awards several times.

Theme of this issue

1 hour to master the theoretical knowledge of effect drawing lighting

Contents of this issue

This lesson is divided into two parts: the first half, discussing basic lighting scenarios and some necessary settings; the second half, discussing the most fashionable current ones in the form of an index, all of which can be seen in the V-Ray for 3dsMax indoor rendering process Reproduce the ambient light and artificial light lighting scenarios received, and explain the key parameters. Due to the limitation of the duration of the open class, the description of the lighting scene will be more in the form of an index and ignore the software operation process, and it is inevitable that there will be omissions. It is a verbatim transcript of the public class, so the grammar is not deliberately modified, sorry for the inconvenience.

Before I start, let me introduce myself and the content of this class, the opening remarks. Everyone has this set. I'm new here, and I want to pay homage to everyone. I tried to speak as flatly as possible, and finished it in a few minutes.

You can call me by my name, or by my screen name, Glass Transparent Man, referred to as Glass. Some comrades with dirty minds, say, oops? Does your name have a special meaning, because you know that this word means homosexuality, although I personally do not discriminate against this sexual orientation, but I have to emphasize, no, it was my online name ten years ago, at that time The Internet environment is not as diverse as it is now, which is an improvement in social morality. But it is easy to cause some misunderstandings.

An example is when we watched Stephen Chow movies, there was a big SB, Shaw Brothers movies, but no matter how you look at it, it looks like a curse. My name is basically the same as theirs. I have suffered from the disadvantages of the times, because I am used to it. , that's all.

As for this public class, you know that in general public classes, the form is usually larger than the reality, so I deliberately chose this topic, because the lighting principle in rendering is not too complicated, and it can be covered in an hour, so It can exist and be discussed with you as a separate section.

That’s because of the teaching format, because it’s viewed on the app, so it’s destined to ignore the operation process of the software, so it happens that only lighting theory can be taught to you in slides, unlike the software operation process, how do I do it? This model is difficult to come out in graphic form.

You may want to say, what should I do if I don’t know the software parameters? In this class, I will show you the changes in parameters in the form of a graphic comparison, but this class is not about parameters and software processes. And if you have no foundation at all, for example, you can't activate 3dsmax, it can only be said that you have to have some knowledge prerequisites to watch, although I don't want you to leave, but there is no way to do this, you have to understand, after all, open classes You can only choose one topic, get rid of those things that need to be prepared to understand, and choose some that are more ornamental, just like singing operas, just watch the opera instead of watching the practice process, so that you must have a certain software operation foundation to listen to this class , no matter how low it is, this threshold still exists.

Well, let’s get back to business and start today’s discussion.

In this class, we mainly talk about the theoretical issues of lighting. Some people say that renderings still need theory? Whether it's lighting, materials, or rendering principles. If you don't understand the relationship between basic physics and rendering, you can't understand how exposure occurs, why 255 represents total reflection in the shader, what is specular heterosexuality, and how does depth of field work? These are all based on physical rendering. If you don’t understand these principles of rendering from a realistic perspective, then you can only learn about the operation of software parameters. For example, if I adjust this certain scene, it will be brighter. I don’t know why it is brighter. I adjust the index exposure and overexposure. There is no more, why is this? I have no idea.

So many people regard photo-level rendering as an artistic thing, but you have to know that photo-level rendering is the foundation, because we say the so-called interior renderings, its fundamental purpose is to avoid contradictions after construction and provide a relatively low-cost preview . Technically, it should be close to reality, because what you make, whether it is a lighting model or something else, is trying to be close to reality. In an ideal situation, every designer should be able to make photorealistic renderings, so that they can You can have the ability to test your own design level, but it is a pity that photorealistic rendering is even regarded as a pursuit. Many people seem to be very good at producing pictures. I still hope that this can be popularized, because it It is not difficult to learn. Ah, this is a bit far-fetched, let's get back to the main story.

So if you don’t understand the principles of rendering from a realistic perspective, or the basic rules, just watch the tutorial and simply imitate the software process, it will be difficult for you to truly have an independent lighting and material, and you can only apply it when you encounter a new project Things in the past or you have to learn other tutorials. How to put it, in this situation, you are not learning how to weave a fishing net, you are learning how to eat fish.

Then this class, we divide it into two parts, the first half, discuss the basic lighting theory and some necessary settings, the second half, I will introduce all the indoor rendering processes you can use in v-ray for 3dsmax in a very brief way Able to see lighting conditions and explain key parameters. So you can see that this is actually a relatively big topic, but I started talking about it. Due to the length of this class, I can't break it down and talk about it with you, so there is only one index.

2) LWF (10m)

First of all, for a real lighting scene, you must open a linear workflow, which is now commonly referred to as LWF, but it is not the focus of our lesson, you just need to remember that LWF is not an optional enhancement effect, nor is it an artistic effect , which corrects and fixes bugs.

I remember that a few years ago, many people were still arguing about this because they didn’t understand the principle of LWF. Then I also saw that some people insisted on not using linear workflow, but superimposed a 2.2 curve on it in the later stage. Well now, whenever you install a new generation of v-ray and 3dsmax, the linear workflow is already enabled by default, and you were required to set it manually in the past.

Someone asked, why don't you talk about LWF, and to be honest, this thing is not suitable for public lectures, not about hiding private issues, because it is rather boring. After watching the whole class, I almost didn't learn any operations. You understand the meaning behind those few options. It is very unsuitable for public lectures, because it takes a long time for us to understand those knowledge points, public lectures, business promotion, you know.

If you are really eager to understand the principles behind the linear workflow, I recommend you to watch a linear workflow video called Han Shilin. When I wrote the book myself, I spent about 20,000 words of graphic introduction. I will have time in the future. I will slowly post these things. Well, the linear workflow is explained here.

3) What is light (15m)

We talk about lighting theory, and here I want to explain that the theory mentioned here is something that is convenient for you to understand, specifically, it is a number of principles that guide our work. We have just been talking about rendering from the perspective of reality. In a word, we have to see what light looks like in reality before we can imitate it in rendering and correspond to it. Well, the first question is, what is light in reality?

Light is a mode of transmission of energy. The reason why the light source emits light is because of the motion of atoms and molecules in the light source. There are three main ways: thermal motion, transition radiation (including spontaneous radiation and stimulated radiation), and light radiation generated when charged particles inside the material accelerate.

Here's a description I took from Wikipedia. I don't think the people who took this class and myself can understand them, so it comes back to what we said to explain the rendering from the reality of ppt, not to learn physics, its purpose, but to better operate in The knowledge of physics in rendering is just a better mobilization practice, so what physics should a rendering artist master?

When a beam of light is projected from (A) onto the surface of the medium, we imagine the light as several particles, and they will propagate differently according to the medium they touch. That's enough, you remember a few key words, just particles, ping pong balls, will bounce. Gone.

Then some people may say, is it too simple to understand this way? I say no problem, because the key is to operate the software and let it calculate the result we want. How it is calculated and why it is calculated that way is the developer's business. , engineers, and programmers, we only need to know a general idea, you know why there is light under the table, oh, it is the bounced light. That's it, very good.

Then let's talk about lighting, we commonly call it lighting, what exactly is it doing? A simple answer is to give the scene brightness. But I think it's better to call it a realistic lighting effect for the scene. So you say it means the same thing? I tell you differently, because the former is unlimited. For example, there are no spotlights during construction, but some renderers will put spotlights on the renderings. If a spotlight would look better or be beneficial to the project, it's a design flaw, and the design didn't take this into account at all.

So if you are aiming at a designer, then this unlimited method will let you use the fill light effect indiscriminately, oh, it’s not bright enough here, we don’t think about how to improve the design, just make a one in the software that doesn’t exist in reality something, let it light up.

So if you look at the so-called business graph style, it is not based on reality. I'm going to give you an example to show you why authenticity is the basic principle. For example, in the picture below, the spotlight is brighter than the sun. This is something you can see in many so-called commercial renderings, and I exaggerated it.

In the picture on the right, ambient light creates a color that does not exist in reality, so it is not called an interior effect picture, but an interior fantasy picture. The brightness of this light is not enough, so we just fill in the light or something to make the night look like day. Please note that I am not talking about whether it looks good or not, but what is the basis of an interior design rendering. We don't want to criticize, let's come up with a criticism. You can also learn how to deceive customers or designers by making such pictures, but we always need to know what relatively active renderers or designers do. It cannot be said that the market is like this. Reasonable. There is a problem if there is too much difference between makeup and plain makeup.

I hope everyone can understand this. If there is an opportunity in the future, I will tell you similar rules about the material course. Of course, the theory is much more than lighting, because the material course involves a lot of parameters, and I will talk about how to reproduce and correspond to reality for each item, so as to ensure that you can make material shaders that are almost the same as reality.

So you have noticed that what I have been emphasizing, or what this class emphasizes, is not for you to make good-looking pictures. Whether the pictures are good-looking or not is a matter of your personal design ability. Engrave what happened in reality, this is what the technical class really needs to do, so that you can test your design before construction, instead of saying that the more realistic the better, if the picture I made looks good to you, then it is a design Looks good, my technology is just to reproduce the good-looking design in the rendering, there are too many ugly things in the real world, even if the technology reproduces reality 100%, it is still ugly. This is a basic logical judgment, not that the more real the better, but the things that are already beautiful or will be beautiful in reality, you just draw them, I hope you understand this.

4) Shadow (20m)

Before starting the formal course, I would like to introduce you to two necessary knowledge about lighting. You noticed that I am talking about lighting now, not lighting. These two are different, and lighting also generally refers to texture lighting.

Now imagine a scenario: Your client tells you that the edges of the rendered shadows are too sharp and should be slightly blurred. Is there a solution? It seems not, we don't know what the sharpness of the shadow has to do with it. You know shadows are cast by lights, can you figure out how to do that with lights?

Let's try to increase the volume of the light source, from 50mm to 300mm, press render, let's see the result:

The shadow has become much softer. Why does the shadow become softer when the light source increases? This involves what happens when photons propagate, let’s look at a schematic diagram:

If you think of your light as individual particles, assuming that the light source does not spread (regardless of other principles of light), the lines generated by it are as shown in the figure above, showing straight-line propagation, and you will see that after the light touches the object , the resulting shadow will be very sharp, as we have seen before. And why does a larger spherical light source soften the shadows? look at another diagram

The shadows of some rendered works are very fake and have a very floating feeling. This is caused by the use of incorrect lights, because in the real world there is no light source that only emits light but has no volume, and there is no perfect sharp shadow ( means in theory). Now that we understand the principle, you can freely create a shadow overlay effect like this, which consists of multiple small spherical lights:

5) Inverse square law (25m)

Another useful knowledge is the inverse square law. ——In this rendered scene, there are floors, ceilings, orange-yellow plastic letter plates, and simulated photography lights.

These are two sets of tests I've labeled A and B. You can notice that, while maintaining the same brightness (I use some exposure manipulation tricks to make us see better, but I won't discuss how this is achieved):

In experiment A, the light was very close to the subject, which caused the G letter close to the light source to have an obvious difference in brightness compared to other letters, that is, we could not get a good and balanced lighting effect; while in experiment B, The light is farther away from the subject, which results in well-balanced lighting for all three letters. ——Purely due to the distance of the light.

What is the reason? The inverse square law is at work. What is this? As software operators, we only need to understand the popular explanation of this law: when the light source is close, the attenuation of light will become faster and the density will be higher; and when the light is farther away from us, the attenuation and density of light will be will drop accordingly. You're taught in many photography classes how the inverse square law works. Indoor rendering is actually relatively rare, because indoor lighting is almost fixed, and it is difficult for you to deal with the problem of the distance of light.

Then our two little knowledge, the problem of shadow and inverse square ratio, stop here, now everyone take a break and clear your brain. Let's go to the next part, because the knowledge starts all over again.

6) Introduction to Lighting Scenarios (30m)

Well, before I dive into the software demo, we're going to specify a few things. Because in natural language, there are many abstract and metaphysical words, such as atmosphere, atmosphere, the color is very gentle, and the shape is very tough. They are used as adjectives or modification of articles, which are copywriting and literary things. problematic, but to discuss specific technical issues, they are no longer appropriate.

Technically, I ask you, all the lighting you can see is essentially just a combination of color and intensity.

So, at least in our courses, I divided the light that humans can see into two categories in the ppt. One is ambient light, which we just mentioned, or natural light; the other is artificial light, or Talk about indoor light, but I think this definition is inaccurate. For example, how do you define outdoor street lights? You also need to talk about outdoor light. There are too many nouns, so let’s remember 2, artificial light and ambient light.

On Earth, the only natural light is that brought by the sun, of course, I say this, not rigorously. For example, what is the light of fireflies, and what is the fire in the fireplace? But as I said, it is too rare or very special, and we are not doing theoretical research, so you can probably understand it. Therefore, in indoor rendering, we talk about natural light and ambient light, that is, what the sun brings is the scenery outside the window and the reflection of light from such buildings.

Due to this premise, in the interior visualization design, you can only see three different and typical lighting situations.

The first type is pure sunlight. You should remember that at the beginning, we said that light will bounce, so diffuse reflection and reflection occur. In this reference, the sunlight is projected outside the window, outside the opposite building, and bounced from the opposite building or the ground to the indoor light, illuminating the entire scene. Of course, there is also the scattering of the atmosphere, but in general In other words, it was brought directly by the sun.

The second category is not pure sunlight, but cloudy. The cloudy day is about to be divided. Think about it, sometimes it rains and thunders, do you want to turn on a small desk lamp next to your house? In this case, the lighting of the scene is a mixture of ambient and artificial light. Of course, there are also pure cloudy and cloudy days. To be precise, the sun is weakened or not directly casting shadows.

So in the pictures you see, many people refer to the mixture of ambient light and artificial light as the contrast between warm and cold. Of course, there is also a contrast between indoor and outdoor, or the contrast of specific weather.

The third category is that the sun is going down (increasing the tone of voice). At this time, the sunlight will disappear and be mixed with moonlight or city lights. Of course, the main lighting at this time is artificial light, or indoor light. Light, that can't be helped.

These three types of lighting scenarios are actually a mixture of ambient light and artificial light, displayed under the intensity and color of different light entities, such as table lamps, wall lamps, and light strips. That is to say, in terms of technology, as long as we can grasp the color and brightness level of different light sources, then we can create a real lighting situation. Doesn't it sound very simple.

Well, now that our theories and basic principles have been discussed, I will take you through all the implementation forms of artificial light and ambient light in the software, and organically combine these theories. If you have a good grasp of software parameters, then after this lesson you should be able to handle lighting situations in all types of interior renderings.

Then you listen to me like this is very simple, as long as you master the software parameters. Then why many people said in the past that the lighting was not good enough, and the lighting of the scene was messed up. What's going on? In addition to being unfamiliar with software parameters and drawing processes, a big problem is the problem of linear workflow.

The linear workflow was proposed around 2005, and it was the default setting after version 13 or 14, I don't remember. However, due to the backwardness of domestic software education, you know that many people still insist on using the CAD07 version, and the popularization of this thing has been relatively slow.

Here I remind you again, you must open a linear workflow. Because it presents the physical lighting situation, if you don’t use the linear workflow, the propagation and attenuation of the light will be very fast. At this time, you have to use the so-called fill light under the traditional process to supplement those places. I have seen it in the past There are a lot of tutorials that are misleading. I can’t give you a name here. A certain business diagram tutorial, what vraylight to use, and modify it level by level. After you read the lighting process in the linear workflow, you will know why This method is so stupid. I hope you understand that linear workflow is not an enhancement, it's the foundation. Let's not fix what's wrong, but do better at what's right. Of course, we just ignore the nonsense that linear workflows cannot do night scenes or business graphics.

7) Ambient light: VRaySun and Sky (35m)

First we'll look at ambient light, by which it will show you how to render realistically.

The composition of ambient light, on the earth, consists of the sky and the sun, then you may ask, what is a city? There is a term here, and many comrades may know it, location, generally this kind of location, for the sake of efficiency, we use the location texture to process, that is, a picture, but this involves some material knowledge, this lesson We won't expand it. In the next course, you will see it appear, but I won't tell you. This is an explanation.

Looking back, what do we do with the sky and the sun? The most popular one now is also the most commonly used abroad. In the vray for 3dsmax process, there are two common ways to deal with ambient lighting, but do you think there are other methods? In the past, there were many simulation schemes, such as parallel light, Spherical light directly acts as the sun, but our software and technology continue to improve, and these solutions have gradually begun to be phased out. HDRI is starting to slowly become mainstream.

Let’s talk about the first one first, VRay Sun and Sky, VRaySun and Sky, I think if you have been to elementary school, you should know these two words. As the name suggests, this thing is a set of V-Ray’s lighting system for dealing with the sky and the sun. In simple terms, it is a light entity based on the real sky data on our earth.

Now is a basic knowledge: different real lights are lighting entities in software, which are used to simulate different effects, which is designed by the renderer manufacturer. Some comrades may have a lot of concepts for me. If you understand these basic concepts, it is very good, and you can quickly enter the specific operation. But if you don’t know these tools very well, it means that the progress of this lesson may If your learning progress is exceeded, you need to add some basic software operation knowledge. If possible in the future, I will talk about it.

VRaySun is what we call light. It is used in the renderer to generate brightness. The renderer is a realistic simulator. Of course, this concept can only be emphasized repeatedly when we talk about materials. I have always told you to render from the perspective of reality. The reason for the ppt is that the renderer is a realistic simulator. But for the sake of the brevity of the whole course, let this point be ignored for now, and you just pretend that you know a little bit.

This is the effect it simulates. The sun and sky of each event segment can be produced with this system.

You can click on the sun icon in vraytoolbar and drag it in the scene, or you can create one from the lighting menu on the right. I hope you can understand this picture, because the design of this class is for desktop sharing, I should teach you online video, you can see the size of my slides, so here, I have to use pictures I'll show you the description in this article, if you really don't understand, I'm very sorry, you may have to watch some other video tutorials.

After it is created, it will ask you if you want to add a vraysky texture. Well, please note that the concept of texture may be very clear to many comrades, or you may not know it at all, it doesn’t matter, you probably know what it means. Sky texture, how to understand it. You can think of 3dsmax as a universe. But in this universe, you can change the wallpaper at will. It was originally dark, but now I added a glowing wallpaper to it, which is the color of the sky. That's how you understand it, this is the most abstract metaphor.

After adding it, you can see the sky in the environment when you press the shortcut key 8, and it will appear.

Ok, so why do you say sun and sky, I said it is a system before, what does that mean. Because the sky on our earth is colored because of the sun, but it is impossible in the renderer to say that we have another atmosphere, or something to simulate this thing, so the engineers directly collect real data. For example, assuming that the brightness of the sun is at noon, the time I am talking about here is actually the position of the sun. You should pay attention to what the sky looks like when the sun is at noon. segment data. Finally, such a system was produced.

Then this system, the main parameters, shall I show you one by one? No, it’s not because this is a mobile phone, I can’t demonstrate it to you, even on a computer, I won’t tell you the parameters one by one. Then you are curious, do you think that such software parameters cannot be learned? No, why, look at your computer keyboard, is the space bar, the enter key, the twenty-six letters, and the pause key on the top most commonly used? But it is useful occasionally. Once I explain this parameter, it will be a waste of time, and you will forget it after learning it. So what should it do? There should be something like a dictionary, if you forget, look it up. Then you said this thing, is there any, yes, official help. But the official help is in English, and the text description of its parameters is not intuitive, what should I do?

I prepared a 22-month-long parameter manual by myself, which translates all the options of vray, and almost every parameter is accompanied by a graphic comparison made by myself, plus a parameter manual composed of my own experience . (Of course I can't release it here, there is a commercial protection, I hope you can understand.)

OK, let's see how this works. First of all, your vraysun lighting has such a long list of parameters. Due to the length of time, I will only show you a few main parameters here.

Intensity, size, turbidity, ozone, explained in conjunction with the parameter manual:

The rhetoric reference when explaining the above parameters, do you still remember what we just said, what is the relationship between the sharpness of the shadow? Let me go through the verbatim draft and what's next.

8) Ambient light: HDRI (40m)

Just now we have talked about the vray sun and Sky system, this system is quite easy to understand, and then we just said that another common processing method for ambient light is HDRI, because HDRI is another lesson, this is me and Luoluo Speaking, she said let me make some dry goods, I said that I am all dry goods, I am afraid that there is not enough time, I can’t expand here, you can’t say that I can learn all about rendering in this class .

So I will briefly tell you here that HDRI is a texture, and then use this texture to illuminate. You may understand well.

If you know simple image processing knowledge, for example, there are 256 levels of color, 0 to 255, which we usually call 24-bit Srgb color space, but it only has 255 levels, right, if we say it is not simple? But you think, the brightness of the sun cannot be said to be just 255 levels greater than our desk lamp, right? So the 256 levels are not enough, what should I do? HDRI is to deal with this problem, it can make your brightness changes very delicate, far more than 256 levels, how to achieve it? I will not expand on this process.

You said you didn't understand? It's ok, I have a picture here:

OK, so what did I say about HDRI lighting? You may have seen a kind of rendering called panoramic rendering, HDRI is the same, it can cast light in the form of a spherical environment.

If the HDRI environment resolution is clear enough, you can use it to render the following image:

Get direct access to lighting, shadows and background effects for a sky.

So you can see why I said that HDRI is more and more commonly used, because vray sun and sky is a simulated sky, it can't get all kinds of sky conditions, unless you go to make clouds, but if you have that spare time, you can directly Solved it with HDRI. So it may be the main direction of CGI development in the future, we will use less and less procedural lighting, as you can see

For things like vraysun, one HDRI can solve all lighting effects. These are all images I did with HDRI before, and you can see that the shadow formation is not inferior to what is done with procedural lighting.

How to use HDRI, the easiest way is to use the texture directly in the environment: remember, select this spherical environment. Of course, you can also use textures in the environment panel of vray, or attach textures in the form of domes. We will talk about domes later.

9) Artificial light collection: VRayLight (45m)

When I was talking about ambient light just now, I mentioned procedural lighting and texture lighting. Don't be scared by the nouns. Texture lighting has just been said, using map lighting. The so-called procedural lighting means that the program simulates a light emitter. In reality, you want something to emit light with various electrical structures, but the renderer will not let you do this, but provide a simulated thing that emits photons. . Different renderers have different names. In vray, there are 2 program lighting mainly used for indoor rendering, and this is also 2.

Then you say, there are so many lights in indoor rendering, wall lamps, light strips, spotlights, downlights, chandeliers, floor lamps, bedside lamps, and table lamps. Why is it solved for him with only 2 lights here? Because you can see that these wall lamps, light strips, spotlights, downlights, chandeliers, floor lamps, bedside lamps, and table lamps all have a very strong commonality. What is it? The shape of its light source is simple, you see, it is either the original shape, or a rectangular light strip, and the filament is a little more complicated.

So here, for artificial light, you completely compare the following three elements to solve all of them, one is color, one is intensity and the other is shape, right? Then there is no more. So general lighting is nothing more than we adjust the corresponding software parameters and compare them to achieve the three similar elements in reality. Of course, it cannot be completely close, but it can be very close to meet the observation of human eyes.

If you open vraylight, you will see a lot of parameters. If I go to the formal class, if I finish all these parameters, it will be very procrastinating, and many parameters are tasteless and it is a pity to discard them, so I Just explain the most important parameters. If you are interested in the rest, you can check the parameter manual, which are all in the form of pictures and texts.

Vraylight is called general lighting because it has a type of switching. If you want it to become a ball, it becomes a ball. If you want it to become a rectangle, you can also switch to a rectangle? :

Now, I will show you the key parameters, and then I will show you almost all the forms of artificial light that appear in interior renderings, and how it does it.

Then come to find, the three elements we just mentioned,

Where is the color parameter? Look at the interface, if you have some software operation background, you will know to change the color from here, needless to say, it is the color selector of the traditional 3dsmax RGBHUB. There is a unique thing here called color temperature, you know what I am going to say, the expansion is another thing, so I will not expand it, let’s take a look at a picture.

I think this should be obvious at a glance, so I won't explain it.

The color is found, where is the intensity?

This parameter needs to be explained. This has a unit setting. Many people are confused by this thing. In fact, it refers to the conversion between different units. Do you still understand this? Look at the picture.

For some units, the energy, that is, the brightness, will only change when the size becomes larger. For some, it is useless to change the size, and only the energy parameter can be changed. The default mode is both. Personally, I am used to using the W tile mode. If you sometimes find that the graph does not light up no matter how you change the parameters, it may be that the unit here has been moved.

The last question, shape, where to change the shape? Vraylight provides us with five different shapes by default, namely plane, sphere, disc, grid and dome. The first three are easy to understand, just as the name suggests, I will show you an example later. The meaning of the latter grid is that it can turn your model into a four-sided light. For example this one:

Mesh lights allow us to create filaments, light strips, or the effect of a polygonal softbox like the one below. Of course, this should be done in combination with textured lighting.

The meaning of the dome, because we just briefly talked about the problem of ambient light, the dome, if you think of it as a big pot with the lid off, it is actually a program lighting for a spherical environment. This is the grid light and the dome are two special ones.

10) Artificial light collection: VRayIES (50m)

When we talked about grid lights just now, we solved one thing, which is the treatment of filaments. Here I have prepared a scene to see the interior lighting part. Spotlights or downlights, light strips, and floor lamps, these three types are actually the most common prototypes we see in indoor rendering. For example, light strips can be circular or rectangular, and floor lamps can also be rotated. Be it a table lamp or a wall lamp, all use light bulbs. So you learn the original form, and then you change yourself.

Let’s talk about the floor lamp first. You may think that the floor lamp and the chandelier just mentioned also have filaments in it? So this example is not mainly about how to do it, because the basic light of any desk lamp comes from the filament, but you can sometimes see some models, the desk lamp is a spherical VRayLight, why?

Because of being lazy. I really won’t lie to you, because the spherical light has been tested, and it has the same effect as we make a bulb inside and create a filament to do it, so when lighting a large area, for example, if you want to make a shopping mall, There may be hundreds of lights, and if you use grid lights for each one, the calculation will be relatively large. So there is a simple method, using a simple method, many people like to use spherical light when the filament cannot be seen, not to say that when we do photorealistic rendering, everything should be done according to reality, but only in terms of effect, the form is not important.

Then there is the part of the light strip. In the picture, this is a special shape. Ours is this rectangle. How to do it? Many people are accustomed to using rectangular lights to deal with light strips. Here we just discussed that we can use meshlights to do it. Why? Because of laziness and convenience. The reason is unassailable.

This is how the software works. But I want you to pay attention, now there are more flexible light strips, and there are also light tubes, but if it is a light tube, your length cannot be like this. ppt, so the real light strip effect in reality is short, just like this picture.

But does it look good? Not necessarily, so this is why our so-called rendering is sometimes better than reality, and we have removed some unsightly things in reality. But do you think there is any problem with this? For example, the authenticity and rigor are lost. I think this may be the same as a little girl's makeup. Will you allow me to remove the slight blemishes? This is a question of rendering artistry. However, if you really say that you are afraid of commercial dangers, for example, if a customer says that the light strips are made differently, then there is no way. There are flaws.

Then we will talk about the last spotlight of this lesson. A very remarkable feature of the spotlight is that you can see the so-called light cup projected on the wall, which is very expressive and has a shape. In this case, if the physical model is used in rendering, for example, the caustic structure is created. It is very troublesome and time-consuming, including rendering, so I recommend you to use VRayIES.

IES is called a photometric network. What is it? In a word, it is a format for recording the distribution of light. The renderer can reproduce the lighting situation depicted by this IES file by reading this format.

Let me take a look here, oops, originally there is an automatic grid technique, because of the app, I can't demonstrate it. If you understand this light, then you know that 3dsmax also has a photometric network, why not use it, because the optimization of vrayies is better, the speed is faster, and the effect is similar.

Well, key parameters, such as color and intensity, I won’t talk about it, the only thing you should pay attention to is this parameter: pay attention to the shadow area

Well, this is some demos of artificial light, VRayLight, VRayIES, some small examples. In fact, you should notice that in this scene, I used VRayLight to do the direct lighting of the window, but I am not going to teach you how to do it now, because if there are too many knowledge points in a class, you will not be able to remember it, so you Just learn the part I taught you, do your homework, and it's gone. Because you can use several methods and parameters to make a certain realistic lighting, and you will come into contact with more different light source types and production schemes when you do cases in the future.

Thank you for watching. We will see you again when we have a chance. I hope that next time I can talk more about the operation of computer software, because it is indeed a little inconvenient to teach on mobile phones.

This is the end of this issue,