Tutorial Core Concepts of Lighting and the 3-point light system

Saki_Sliz

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May 3, 2018
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This post was first made as a reply to this thread, and it was suggested that I share it here.

This post covers some basic ideas of lighting techniques, with a focus on talking about the 3-point light system. this is going to be a lot of copy and pasting.

Here is the layout of a basic scene (using blender).

_0 Set up.png

Now here is the basic ambient lighting, basically the flat colors (depending on how your program renders light).
I always keep this very dim, since most of the other lights are going to fill in the scene (and global illumination aka light bouncing is going to create the same effect as ambient lighting just like in real life.)
_1 ambient light.png

Now the first lamp
Key Lamp/light
just a point lamp
THIS IS CALLED HARD LIGHTING
do you see the edge of the shadow on the ball, and on the wall.
notice how sharp and crisp that transition is, this is called a HARD EDGE.
hard edges with the shadows make images look fake, even with real-life photos, they don't seem natural.
this happens when the light comes from a physically small source
like a tiny flash light.
you want to avoid this (and it looks like you are doing an ok job.)
_2 Keylight hard.png

This next image is the same key light
but the size is bigger
THE SHADOWS ARE NOW DIFFERENT
the shadow on the ball is smooth (hard to tell)
the shadow on the wall is now so smooth, or blurred, it is almost hard to see it as a shape
the smooth transition is called A SOFT EDGE
this lighting is then called SOFT LIGHTING
what photographers will do is shine a light into an umbrella or paper box to make it seem like the light is physically bigger.
the thing with doing this is that small details still have crisp shadows, while the shadow of something far away (say the shadow for the leaves of a tree reaching the ground) gets blurrier or fuzzy or softer.
_3 Keylight very soft.png
NOTICE!!!
I could have made the light even softer (like bigger than the room), to the point where we can't see the shadow.
how do we know what is enough?
here is the idea, the key light acts as your main light, it is key!
it is going to be the brightest light and the color of the light is the most important (later I will say it much match the scene)
because it is key, the light will be very close to the camera, but to the side (it is unnatural to have the light be directly on the subject). I personally also have the light up a bit, since most of the time when we look at things, light is coming from above.
if the object was shiny or smoother, there would be a shiny spot where more light hits it the most (easier to see in the hard light image). This is called the highlight (or I call it that), and you can still see the shadow very easily. if you make the key light too soft you no longer see the highlight, without both highlight and shadows, the image either looks fake, simple, or artificial. having highlights helps with the 3D feeling that makes an image look realistic, interesting, and even seductive!
Sexy ass spheres!
so you want to soften the key light but still be able to see areas that still well lit by the light such that it kinda feels like there as a focus of light on some spots (for example, I always judge my keylights based on how the nose, mouth, and forehead look).

now that shadow is still to, simple, and artificial looking, so to fix that we use a fill light


_4 fill light very soft.png

with the fill light, this acts as your fake ambient lighting, and it does so by being really soft.
the idea with it is that you want to illuminate the shadows of your character (such as the shadow of the nose on the face, or the shadows around the eyes). It is so soft you can not see the shadow on the wall anymore. the goal is to try to get the shadow on the ball to be smooth out till the point you can not see the start and stop of the light on round things.
now you could have the fill light on the completely oppisite side away from the key light so that it evenly illuminates the shadow of the key light. but I find having the light a bit off, lighting up the shadows unevenly makes things more interesting, I also try to avoid having my fill light look like it is below the subject because the idea is that the fill light fakes the ambient lighting, ambient lighting comes from the light bouncing around or getting scattered by the air, and not that much light bounces up off the ground, but more comes from the wall than anything alse, so I have the fill light to the side, I also actually have it up a little bit because again I find that most of the time having light above things seems more closer to real life.

NOW LETS COMBINE THEM!

_5 key and fill light very soft.png


So hopfully it looks more interesting.
the shadow is darkest on the bottom because of how we located the lights, and this is similar to what happens in real life, so I hope it makes sense to your brain.


NOW to the other important light in a 3 point set up. the rim light (I sometimes call this the halo or highlight light)
this just seems to make things more interesting, maybe because it adds contrast.

_6 rim light.png

basically, you just want to show off the edge/outline of your subject.
I find keeping the key light and the rim light on the same side is a good idea.
I physically have the light be rather hard, bright, and close to the subject, because it is hard to get a bright halo on your subject without making the whole room light up.
adding this effect can make things seem more alive or more 'good' as in good vs evil, an evil character would have a different set up.
I have it in the top right because traditionally I find that is the best way to show off the most amount of interesting outlines (ie the sholder and head, side of body, neck). but you could put it anywhere.
the idea is we are simulating how light will wrap around objects and how in real life our eyes can adapt to a wide range of light intensities, and that there are bright lights everywhere, but we are not looking at them. you can see a bit of light wrapping around the sides of the ball, ever so gently, but not so much the bottom, again just like what happens in real life.

now lets add all of it together.
_7 together.png

Neat!

Now to try and make it easier to understand how this looks, lets apply some skin to the sphere

_8 with Skin.png

great, hopefully, you get a feel of the skin as being realistic and interesting, but the highlight you see near the center, and the halo/highlight you see near the edge.

now on to color!
the first thing I do is keep the rim light pure white, I may make this blue, but mostly white is ok because everything else will be warmer colors so the white light will look bluer relative to everything else (the effect is very subtle and in fact we are using optical illusion tricks. Pixel art is all about trick of the brain and how the brain filters information. pixel art may look simple but it is a crazy tricky science).
as I mentioned most of the time indoors the lights are warmer (almost a yellow, yellow orange, to skin color), you may use something different outdoors (which is tricky), but typically the key light will match the scene (if there is no light in the scene the key light will just be the color of the scene itself and defines the scene), this way it looks like everything belongs in the same image, in the same space, and it doesn't seem like there as a fake ghost light floating next to the camera (which there is).
lastly is the fill light. Light goes through the body, often only coming out red (stick a flash light under your hand in the dark). so in computers, skin is often simulated as a subsurface scattering material to emulate this effect, and as a result our shadows tend to be redder. in fact, when painting, making the shadows warmer than the base skin color is a good way to make characters seem alive and healthy (use blue if you want them to look dead or purple for evil people). So often with the fill light I make things interesting by making it a bit red, I do this almost all the time.

_9 colors.png


These next two images were a mock-up of an issue one user was having. Lights in the ceiling, a mirror, on girl close to the camera the other close to the mirror. Also the characters were rather flat, and seemed to have some odd shading issues. I tried to make the worst shader I could to show off the same issue. but playing around with shaders is a great way to improve things.

01 Mock.png

the image had ok key lighting, that is, main lighting to show the front of the main girl.

So all I needed was to add a film and rim light, actually, now that I look at it more, I would acutally dim the lights and add a new key light, and try to make it hard so that the shadows are more interesting on the female closer to the camera.
I added a fill light, which you can see as a white floating rectangle in the mirror, and I made it slightly red to add colors to the shadows, and I added a spotlight as the rim light. I used these two lights instead of points so that they do not light up the whole room. again I changed the room lighting (and if I had a key light I would change it too) to be a bit warmer, but not so much that it changes all the colors in the image, I kept the spot light pure white (you can see the difference in the mirror, the spot light is reaching the wall (which I can disable) and is white while the lamps are a tinge yellower/orange.

02 Mock.png

the idea is that unless you are going for a very expressive look, the effects should be subtle, not obvious.

oh, and I did the same for the character in the background as well, to make it look like she wasn't just in the shadows. she has her own fill and rim light, slightly dimmer so she doesn't compete with the main girl, and harder lights so that her shadows have enough edge to them to still be easy to see, but I still colored the lights.

I am still testing ideas of color saturation and what feelings they invoke in particular images so I don't know all the details, but this could be something to try or just interesting to read, let me know if it helps at all.
 

caLTD

Member
Game Developer
Feb 4, 2018
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Great... having a 3d pro in our members is good thing.

And as usual here my suggestion. Most of other beginners in this forum can't navigate trough blender interface. Your theoretical tutorial nice and most of us can't follow you in blender.

And I mean Don't be BSD elitist. Please do not misunderstand me, I'm very glad about this tutorial and I'm going after it (because I had load of lightning problems in my 3d game).

If you wonder why PHP language was so spread and wide usage ? here trick because of its default manual at php.org. There where thousands of copy paste examples.

So ?

Do not try to sell us Blender, just put a nice video. Anybody who wants this quality will follow you.

Good luck and keep teach us with this tutorials.
 

Saki_Sliz

Well-Known Member
May 3, 2018
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993
Will you quit it.
I am not trying to sell you blender, it is just the tool I am most comfortable using right now.
Notice how I only focus on the image, not the tool (ie I never show blender interface).
I did this because:

1 that makes this tutorial work for any program you want (ie Daz)

2 This lets you see a goal (ie the image) and be able to compare it with what you can render, as well as give ideas of what you can try.
 
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caLTD

Member
Game Developer
Feb 4, 2018
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Why ? :)

I'm an old fool and you can't sell me anything... When I read your posts I see my young self at 90's. We think we can change world with open source. And try to convince everyone else to use Linux.
 

Saki_Sliz

Well-Known Member
May 3, 2018
1,403
993
Question: Why is it, when you read my various posts, that you get this perspective? Why is it that you perceive me to be, some ambitious child with eyes full of wonder, who wants to share their passion for the world?

I understand that there are Blender users who do act like a simple-minded child who wants to go around and boast about Blender. Blender is not a passion of mine. Building robots, circuit board, and designing/implementing programming languages are my passion, and I would be more than happy to get into discussions about those topics. Blender is nothing more than a convenient tool and toy for me to play with on the side, and I when talking with others about it, I treat it as such, a tool with pros and cons just like any other tool. When you program, you don't ever just use one programming language. When you are designing circuit boards you don't stick with one go-to manufacturer. One should be flexible especially when it comes to business ventures.

Forgive me if I am in the wrong here but: when you accuse me of trying to persuade readers to use Blender, and then despite myself and others turning to discuss other topics of interest, you continue to make responses whose sole focus are to attack and criticize the use of Blender, written with the assumption that I actually care about Blender; I don't know if I should feel personally attacked because you keep doing this, if you are intentionally insulting my intelligence by assuming I am so simple minded that you would think I have a fixation on just using Blender, if perhaps the way I am writing is causing some confusion, if perhaps my level of writing and thinking are above what you can competently process, or if you actually have a mental medical condition which limits you to your fixation on just the idea of pointing out the issues with blender.

Lastly, nothing is wrong with the open-source approach. You act as if it was a cool idea in the 90's that died in the 90's or at least never succeded. Unix and Linux are the most used operating system at the enterprise level. After 4 successful years since Google restructured their internal staff to follow a more open source approach to software design, just this month Microsoft has announced that they too will also be restructuring so that their development process follows a more open source behavior as well. and over the past 2 years I have watched as the electronics community have been motivated by the rapid development in software due to open source, leading to the hardware industry to rapidly work around our limited/outdated copyright system to better support an open source development for hardware so that they too may benefit from the rapid development that open source design enables.

Do not mistake me to walk the path that you once walked. I don't believe in simple ideals. I've had to do blue-collar work since age 5, self-motivated to teach myself algebra, linear algebra, calculus 1 2 3 & 4, physics, electronics, and 4 programming languages all before high school, overcame hearing and communication disabilities without anyone's support, finished a college degree before I finished high school because I could, and am working on my second degree now. I never had the financial opportunity to get to be some starry eye child you think me to be. I do not appreciate being treated as some simple-minded free-caring child, a mistake in misreading my previous post is something I can understand, but since you seem to have some childish fixation, as if it is your mission to save me from myself, it seems you continue to ignore me, and continue to believe in only what you want to hear. I have tried to be polite about it, letting post freely without any major argument or corrections, allowing you to express yourself as is your right, but seeing that you continue to follow my posts and you continue to have this fixation, I can no longer find your behavior acceptable.

Stop making these aimless attacks against my "perceived" sales for Blender. Your conversations offer no intellectual opportunities for myself. Good day.
 

caLTD

Member
Game Developer
Feb 4, 2018
184
165
First of all, I'm uneducated and English is not my first language. I learn everything by myself. So I may have errors in my meanings.

And,

Because, your posts are too long and you are try to explain hour self very heavily, that's why I may think you are some ambitious child person with eyes full of wonder :) . You remind me my younger self. Later or sooner you will get hurt because of this.

And I'm not accusing you try to persuade users, your are actually try to persuade users in your blender vs daz topic

Because you put a small blender tutorial to how blender enhanced than daz3d and you do not put a daz3d tutorial. So from my point of view you are in selling blender business :). (To be honest I do not had enough English experience to explain this in other way, don't get it personal).

And I don't care what are you try to selling, I just try to say take it easy.

Or, you are self made person, which you got lots of talents (I may never reach all of them, and from my eyes I'm quite capable person) and try to teach goons like me very fine aspects of creating 3d content. Even you haven't got lots of money for live easily.

So why the hell you doing this ? Just make your own game hit the jack pot, then get loads of fans and if you want lure them into blender, you can do it much easily.

Also I did not attack you to about blender usage. You miss understanding (or I'm mis presenting). What is I'm trying to told you. You are trying to teach people in theoretically.

Like BSD operating system manuals. They are too ABSTRACT like your tutorials. I'm not saying they are useless or wrong. They are too ABSTRACT. Unix's are better operating systems however ordinary people can't handle interface, like blender.

So, mere minions and unga bungas like me can't follow you. If you wish to successfully sell the blender (or persuade people use blender in their work flow). You will have to make your tutorials practical, even put videos in you tube. Why I care this, because unable to access knowledge was hurts.

LITERALLY, I spend my last year every available hours to build a 3d game from scratch. I do not have any other fixation than finish this game.

To be honest I bit pissed off when I see your post's and try to explain why blender can't replace Daz3d and I believe explain myself and thats it.

Anyway have nice intellectual opportunities. Good day.
 

Saki_Sliz

Well-Known Member
May 3, 2018
1,403
993
Ah, I see. Thank you. So it is a miscommunication issue you and I were having. Glad to have that cleared up. Well, I wish I could say more, but knowing that communication is an issue, I don't believe I have the skill to say much more. Thank you for being patient with me. :)