3D Lighting
How to use the 3 point lighting
February 8, 2010
Lighting. It´s a wide subject. In fact, dreded by many to be the most difficult aspect of 3D graphics. There´s a saying: Lighting will either make or break your render.
Since this subject is infinite, we´ll be better off staring with something simple. The 3 point lighting is the most used lighting set up by professional photographers. In fact, it´s a standard lighting set up and a good starting point for portrait renders. It can be further expanded into 4 point lighting or simply using unlimited lights to suit your various needs.
So, why three lights and where to put them? The three lights are called: Key Light, Fill Light and Back Light. The names suggests what they do, so let´s break them down:
- Key Light
Key means main. Its job is to cast the main light onto your chatacter. In the real world, we´re used to having lighting coming from above. If we go outside, the sun always comes from above and so does the sky, which acts as a secondary light source. Well, unless you live in China and everything is upside down! Seriously, the sun will always stay on top.
Indoors, we´re mostly having lights in the ceiling or at least higher up on the walls. This is to simply mimick to what we´re used to outdoors. So, this suggest that our Key Light should come from above. And it does! Now, having it completely above the character would not lit the face. So that´s the Key Light often is set at an 45 degree angle. Having that done, it would now come from behind and above the camera, hitting our characters straight in the face.
Not pretty! We want some variations in the face. Therefore, again – the poor Key Light is moved 45 degrees to one side of the character. The final position would be, above and on one side of the camera and 45 degrees on both the X and Y axis. The Key Light intensity is often 80-100%.
- Fill Light
Having the Key Light positioned on one side of the camera, creates some nice variations on the face, and some dark shadows as well. The Fill Light has only one job: Fill in the shadows! It´s placed on the opposite side of the Key Light. Often coming from a 45 degree angle above – sometimes midheight. So, both the Key Light and Fill Light are positioned behind, above and on each side of the camera. The Fill Light is often much weaker than the Key Light. Around 25%-50% is usually a good intensity.
- Back Light
The Back Light, is the final light in the 3-point lighting set up. It has a single job: To cast a strong light coming from behind and from the side of the character. Why from the side? Well, here´s the thing with the backlight. It separates the character from the background and craetes a silhuette effect. If we were to put it straight behind our character, it would not be visible on the caracter itself. So, again – 45 degrees behind and above the character. The backlight can often be a lot stronger than the Key Light, because of its steap angle. A value of 100-200% usualy works good.
And that´s it! You can add a 4th light to the mix – a secondary Back Light on the opposite side of the first one. So you would end up having two Back Lights – both from behind and above the caracter – coming from each side of the character.
If you like, you can also add a 5th light, a so called Bounce Light. I often add one to get a sense of light bouncing off the floor. This light is often placed at ground level, infront of the character facing up. Usually very weak in intensity, around 10-15%.
Now, get out there and have fun!
You can download a free Basic Light Set for DAZ Studio and Pose that uses the above techniques:
https://www.dream-lounge.com/dreamlight/downloads.htm
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How to light outdoor scenes
January 13, 2010
You may think that outdoor lighting is more difficult than indoor lighting. I would actually say it´s the other way. Outdoor lighting is much more simple to achieve!
Let´s pretend you´re a photographer and go out a sunny day with a digital still camera. Yeah, you got that right – you can´t move the light! The sun is where it is – and you can´t do much about it. The only thing you can do, is to move your models, and your camera.
Now, while walking around, we notice a car. It´s hit hit by the sun and casts a nice strong shadow. But take a look under the car. There´s a secondary shadow underneath! Where does that come from? This is the secret with outdoor lighting. We have two light sources, not a single one.
We have the sun light, which is a small and sharp light source. And we have the sky – which is a huge light source – thus producing soft shadows. Just like the one underneath the car.
Luckily, we can move the sun in our 3D scenes, but really – that´s the only thing we need to move. The sky light will always surround the scene in a similar way – no matter if the sun is there or not.
So how do we set up the lights?
For the sun, a bright orange colored Distant Light will do just fine. At mid day, it´s high up in the sky and aims almost straight down. Closer to evening, it´s lower in the sky, with a more deep orange color, almost touching the red spectrum.
And the sky? There are several ways of doing this. One is to add a sphere object into your scene and map it with a 360 degree panorama – which can then be set to emit light via Radiosity. This would automatically lit your scene and mimic the sky light.
The other way, would be to simply add an area light above your scene, and make sure it´s big enough to cover all of it. Add a bright bluish color or a more greyish one if you´re planning on doing an overcast scene.
We can add ambient light – an even all over lighting to mimic the overall light bouncing that occurs outdoors – but we don´t have to.
You can render with or without Radiosity. The latter will of course take longer, but will give more realistic results, as Radiosity will calculate all the light bouncing going on. Balance the sun and sky lights with a strong enough Radiosity setting and you´re done.
If you want to get more professional results, try adding the sun so that it hits your scene from the back, side and above. Professsional photographers use this to enhance the silhuette of the models, so that they break away from the background. You can then add an additional light coming from the same direction as the camera, to lighten up the shadows on your model. (Like using a bouncing reflector in real world photography).
And that´s it! Midday, outdoors lighting is my favorite lighting set up. It´s just THAT easy!
How to use Distant Lights in 3D
January 12, 2010
There are several light types in 3D, such as Spot Lights, Distant Lights, Points Lights and Area Lights to name a few. The most simple one to use is actually the Distant Light, also sometimes referred to as Inifinite Light.
What it does, is to illuminate every area of your scene with parallell rays. That means every single pixel of your scene will get the same lighting. Of course, your scene will react differently to this, depending on the props / surfaces you´ve got in there.
A Distant Light does not have any position, since all rays are equal. Therefore,you could say that a Distant Light´s position is infinite. This makes it easy to use, as you only need to worry about it´s rotation, which is the anlge at which it hits your scene.
Distant Lights are best used to mimic outdoors lighting. Our sun is actually not a “Distant Light” – it´s a large Point Light (A single point of origin and multiple rays in various directions) – or even a Sphere Light (See this as a sphere with rays coming out of the surface). However, since the sun is at such a great distance from Earth, and is such a large object – we can safely perceive the rays hitting our planet as almost parellell.
Take a look at this video, that demonstrates how you can use such a light, and how you can take advantage of objects in your scene to cast shadow patterns and make your scene look more populated that it actually is.
