Configuring 3D lighting is similar in many ways to what is done in the real world with photography and video. One of the easiest to create and reliable lighting methods is the Three Point Lighting model.

The Key light is usually the first light added. This is the main light used to illuminate the subject of the model. With the subject as the center of rotation, the key light should be above the subject at an angle between 15-45° and between 15-45° on either side of the camera.

The Key lights the model but leaves many other areas of the subject dark and in shadow. A Fill light adds light to the scene not reached by the Key. The Fill light should be on the opposite side of the subject from the Key but not as high and not as bright. This light should be no brighter than half the intensity of the Key, and Specular is usually OFF.

The Key and Fill lights make the scene well-lit but the subject blends with the background. A Back light (or Rim light) separates the objects from the background by adding a specular "rim" around the edges. The Back light should be behind and above the subject.

The Three Point Lighting model described will provide predictable and satisfying results. Additional Fill lights can be added to the model if necessary to create more complex lighting models.

Energy is the "brightness" of the light, and the Distance setting determines the "power" of the light, how far the light illuminates objects. A higher setting will make the lamp render "brighter" even though the Energy setting has not been changed. The Distance and Energy settings must be balanced together to achieve the desired results.

Blender has two methods for casting shadows from light sources. The first method is buffered shadows and the second is raytraced. Both have their uses and create different results. Buffered shadows are generally faster to render than raytraced shadows and offer softer shadow effects.

Something to be aware of with buffered shadows is the clipping of individual lights. For the best general results the shadow clipping of each light should encompass the model subjects without extending beyond the model or falling short. Check light clipping by selecting the light and choosing Shading and then Lamp. Adjust the clipping as necessary. It is extremely important to adjust the shadow clipping for buffered spotlights so that the clipping includes the subject and as little else as possible. Improper clipping leads to shadows disappearing at the "base" of objects and other artifacts.

Besides clipping, energy, and distance, there are other buffer shadow settings to adjust depending on the model.

• The Buffer setting determines the size of the shadow mapping, in other words the shadow "detail." Because a higher Buffer setting increases memory requirements and render times, this should be no higher than the minimum required to get the desired results.
• Samples affects how cleanly the shadows are cast in the scene. A higher setting may help make "blocky" shadows smoother, but as with Buffer a higher setting increases processing requirements. Keep samples to the minimum required.
• Bias inversely affects the contrast of the shadows. A lower Bias will increase shadow contrast compared to a higher setting.
• Soft affects the "blurriness" of the shadows. Too high a setting will make shadows inaccurate and almost non-existent.

Lights with raytraced shadows are easier to use consistently than buffered because they do not require as many adjustments, but rendering times increase greatly with each raytraced lamp in the scene. All ray lights except the Area lamp cast defined, crisp shadow edges. This makes raytraced lights very effective for directional lighting.

In the real world shadows are not always defined and generally get softer, blurred, and faded the farther they fall from an object. The raytraced Area lamp simulates these effects and the quality of shadows can be adjusted with the Samples setting. As with buffered shadow lights, increasing the Sample setting will increase render times.

Other Area light adjustments for softening edges are Clip Circle, Dither and Jitter. Umbra increases the contrast of the shadows.

Because of the higher processing requirements of raytraced lights compared to buffered, raytraced lights should be kept to a minimum to lower rendering times. This is especially important for animated models.

The real world rarely ever has instances of a true absence of light. The light and visible color of shadows and the darkest areas of a scene is known as ambient light. As with many other 3D applications, Blender has an ambient light setting that can be found in the World settings under Shading . Make sure to check if the ambient light settings are what you want by looking at the color changes in Materials.

In most situations the ambient light settings should be kept low, usually no higher than 10% (0.100 setting). The added light from the ambient settings will also mean that other light sources in the model will have to be adjusted and lowered slightly to avoid overexposure during rendering. An effective technique for using ambient light is to shift the color towards blues to "cool down" the shadowed parts of a render. An effective example setting is (R) 0.0, (G) 0.02, and (B) 0.1.

As with many other 3D programs, the lights in Blender are point-based, meaning the light emanates from a point and not from a surface. Windows and fluorescent light fixtures are examples of lighting situations which are not well represented by point light sources. The solution is to rig multiple point lights in an array to represent the wider origin(s) of the light source.

Create a buffered spotlight and a grid that is the size of the window or light fixture in the model that is "casting the light." Parent the lamp to the grid by selecting the lamp first, shift-clicking the grid, and choosing Make Parent. With the grid selected, choose Dupliverts in Object Buttons. You may need to go to Editing and Flip Normals on the grid faces to get the lights to face the correct direction. Adjust shadow clipping to only affect the objects lit by the array.

Because many lights are being used, the Energy setting for the array lamp should be lowered depending on how many vertices there are in the grid. Distance for indoor settings should generally be twice the setting required to reach the edges of the furthest object effected. An array light should have Specular OFF.

This lighting array technique can be applied to other shapes and doesn't have to be used only with grids or planes. A chandelier might be better represented by a circle or sphere, so the array size and shape should be based on the needs.

Arrays can also be used to simulate the ambient reflected light in a room. An extremely dim array facing away from one wall and onto the opposite wall in a scene will nicely simulate a more natural effect. Generally the "ambient" arrays should only be arranged to radiate light from the largest well-lit flat surfaces in the model. In most cases this means only having an array on empty areas of walls, floors, and ceilings.

Large scenes, especially outdoor settings, are not easily represented in Blender with a simple lighting model. A suggestion is to use Global Illumination for a more diffuse and "cloudy sky" effect. Global Illumination is similar to a standard lighting array but instead of a plane the light is Dupliverted to a dome.

Create a buffered spotlight and an icosphere. Delete the bottom half of the icosphere in Mesh / Vertex Edit Mode and then parent the lamp to the hemisphere by selecting the lamp first, shift-clicking the hemisphere, and choosing Make Parent. With the hemisphere selected, choose Dupliverts in Object Buttons. You will probably need to go to Editing and Flip Normals on the hemisphere faces to get the lights to face inward.

Because so many potential models are outdoors and need similar lighting, it is suggested that users create a "standardized" lighting model to use as a base for importing into scenes. Our model has four different GI lighting setups in different scenes along with a Sky Dome.

Just as with any buffered shadow lamp, it is important to adjust the GI light in the model so that the clipping includes the subject and as little else as possible.

This Global Illumination method is useful but somewhat bland. Even on cloudy days it is rare for there not to be some more dominant direction of light. The obvious solution is to add one more light (NOT dupliverted) aimed to "shift" the shadows more to one direction. This is the same principle of the Key light in a 3 Point Light setup. When using a GI dome or other GI method it is important to keep this additional light low-powered since the GI method is already lighting most of the scene.

Another method for adding direction to a GI lighting model is to set the added Key light to Shadow Only. This just adds a slight direction to the other shadows making them slightly more realistic.

This Shadow Only spotlight method doesn't work if the camera view encompasses an area outside of the spotlight boundaries, because this method will also "shadow" the edges of the area it is "shining on." Odd and unattractive banding areas may appear, obviously unwanted in your rendering.

A solution is not to use the Shadow Only option, but two spotlights that are in exactly the same position and pointed at the object with exactly the same parameters. Set one spotlight to cast shadows and the duplicate spotlight with no shadows and set as Negative. The second spot will remove the added light from the first shadow-casting spot but leave nice directional shadows behind.

The Global Illumination method doesn't always work well for a "sunny day" scene. A clear sunlit setting will cast directional and more defined shadows. A single light cannot light an entire, large outdoor setting model and still cast proper shadows. A solution is a light array large enough to illuminate the entire model. A single hemisphere lamp is used on the opposite side of the model as a Fill. When using raytracing, an Area light with high size and sample settings will also work, but with greatly increased render times.

As with modeling and vertices, try to efficiently keep the number of lights to the minimum necessary to achieve the desired results. More complex models and more lights in a scene can rapidly increase rendering times. The Global Illumination method and lighting arrays take much longer to render than a more simple lighting method, so try to be as efficient as possible with your lighting setup.