3 point lighting is your friend. There is a lot of reading to be found on the intertron, but I'll give you the skinny version. I'll mostly talk in terms of Max however most of this translates to just about any 3D app and most game engines you plan on using. This is geared toward people who have tried to light a scene and walked away with a headache.
3 Point Lighting:
Actually 4 in some cases
Ambient or Fill lighting:
Normally comprised of a few lights that don't cast shadows, and just raise the ambient level of lighting to mimic the natural light bouncing around in your scene. Normally you have a set of lights that point at the ceiling and a set that point at the floor, and they are set at an angle that will include the walls. They use very soft lighting by turning the hotspot beam down and the fall off very high. A good start value for fill lighting varries by I normally start off with .25. The purpose of these lights is to lighten the shadows cast by the key light. Shadows are constantly bombarded with light bouncing off of objects and coming from other sources so they are very rarely 100% black, which is what Max/Maya will do if you don't wash the shadows out or lower their density. I personally use Direct Lights or occasionally Omni's but we'll get into light types later.
Normally this is your dominant light source and casts shadows. Often its just one light, such as the sun or moon if you are outside and a window or a light fixture if you're inside. The less lights you have casting shadows the better off you'll be. Shadows are by far the hardest thing for your CPU to render/calculate and it is best to start with all your lights set to NOT cast shadows and turn it on only when you need it.
Rim Light, Back Lighting or Bounce Light:
This is used to produce a thin outline around your character. Normally placed behind and above the character as a light placed directly behind will show very little if any at all lighting. Adding "fall off" to the self illumination map slot of characters material can go a LONG way in helping rim lighting.
Shadows cost processor time to calculate. Any light can be set to a negative number and it will subtract light from the scene, provided you set it to white, and turn off shadow casting. This is a good, cheap way to darken areas and fake shadows for non moving objects. It's important to remember that when you subtract light from a surface that you try to guess how much light is actually hitting the surface. Example if you have two lights hitting a cube both lights set to 2.0 and you wish to remove some of the light from the cube setting your shadow light to -1 will lower the total light hitting the cube to 1. Setting it to -2 will erase the lighting from the cube. This is good for some objects that seem to glow brighter then others. By setting the shadow light to only cast on the one object you can correct the light imbalance without effecting the entire scene.
- Spot lights:
These produce light from a single point and it is directed in a specific direction. Unlike Direct Lights the light cast from a spot light fans out like a cone. Think of it as if you where using a pie shape to cast light. The wider the beam the rounder the tip. Under Directional Parameters you can change the beam from a circle to a rectangle giving you a true pie shaped light however the light will still arch between the two end points. You can use a spot light set to rectangle and adjust the fall off/hot spot beam to fan out. This works great for faking light coming in from a square source.
- Direct lights:
work much the same, however instead of the light radiating from a point, you specify a circle or rectangle that emits light. These are good for Fill/ambient Lighting as they produce consistent lighting across large areas. You can also change this light from circle to rectangle, which is handy for illuminating an entire wall.
- Omni lights:
This is a close approximation to a ball of light. Often the first thing someone new to lighting reaches for when it should be the last. These are actually 6 spot lights grouped together. Each light faces a different direction, up, down, left right, forward and back. Keep in mind for each Omni you place it equals 6 spot lights, Omni's really start to hit render times hard, if they are set to cast shadows. So ask yourself, "do I really need all 6 lights or can I do it with a few cleverly placed Direct/spot Lights?". Chances are 4-5 of the lights in an omni are sending out calculations you could care less about.
Found in Directional Parameters Rollout
- Fall off and hot spot beams in Direct and Spot lights. The hot spot beam is light being cast at 100%, the fall off is where the light reaches 0%. Putting these two close together (default settings) will result in a sharp edged light. Setting them farther apart softens it.
- Use Far Attenuation much the same way to stop the light from casting lights/shadows infinitely across your scene. This basically tells your light, start here and end here, blend whats in between. This is pretty much the only way to control the fall off in omni lights.
General parameters & Shadows (Default off)
Found under Shadow Parameters Rollout
Adjust the density of your shadows to make them less dark. This also helps to fake light bouncing in washing out the shadows. Since Max/maya don't actually bounce light unless you use some fancy settings that just eat up your time and give mixed results.
- Shadow Map
: When selected it has its own Params Rollout.
Uses bitmaps to create shadows. You can decrease the render time by using a small bitmap size and blurring the edges to hide any pixel aliasing that might be showing up. They are good at producing soft shadows which is pretty much the work horse of any shadow scheme. Shadow maps are not great for highly detailed shadows or shadows that cover large areas.
- Ray Trace
: When selected it has its own limited Params Rollout
It will cost you CPU time, in a major way but can be highly detailed. There is a point that your shadow map might be so big and detailed that you might as well render with ray tracing. It is not good at blurring the edges of the shadows so this is pretty much a one trick pony.
- Advanced Ray Trace
: When selected it has its own Params Rollout
Same as above but at the cost of MORE CPU time you can blur the edges of the shadow by having it sample the edges.
: When selected it has its own Params Rollout
Like shadow map this produces nice soft shadows with the exception that the farther the shadow gets from the object the lighter and fuzzier the shadow gets. This does a GREAT job of producing shadows that are washed out by bounce lighting. However it could end up costing you just as much render time as Ray Tracing.
It helps to start out in passes, creating one type of light specific for that pass. I find it helpful to label the lights the pass they belong to as well adjust their line color to reflect their purpose, paying close attention to change the color slightly for lights that cast shadows. (See example image below)
It can also be helpful to put the different lighting passes on separate layers.
I'm sure we can grow this section, these are just the few I have bookmarked on this machine. I remember reading way more then just these.
Anyone else have any tips, tricks, links, example files?