Lecture Notes

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• Lights
• There are seven types of lights that can be created.
• Distant-light emits parallel rays from an infinitely distant light source. This light behaves similarly to the sun.
• Point-light emits rays from a given point outward in all directions. An example of a point light is candlelight.
• Cone-light emits rays from a given point in the direction defined by their conic shape. The intensity of these lights decreases at the perimeter of the cone. This area of decreased intensity is defined by the difference between the inner and outer cones. An example of a cone light is a car headlight.
• Projector-light emits rays from a given point in the direction defined by a pyramid that is associated with the source. The rays emitted by such lights are also filtered through an image map, projecting that image onto a scene. An example would be a slide projector.
• Custom-lights that can be created to represent variable intensities of a light source in different directions. Custom lights more accurately represent the uneven light emittance of real light sources. For example, one could recreate the characteristics of a light bulb, by specifying lighting intensity around the irregular shape of the bulb, and having zero light emittance where the socket is located.
• Area-light which is associated with physical objects whose surfaces are emitting light. One can model a curved tube, and turn the object into an area light.
• Line-lights are derived from and are associated with open or closed surface objects in the same way area lights are derived from surface or solid objects. Light from line lights is emitted from the segments of the object rather than the object as a whole.
• When creating an area or line light, pre-pick the line or object, double click on a light in the lights pallet, and chose the desired type of light, either area or line.
• Note: when creating an area light, one has the option of rendering the light as an object. The result of this action is an object that glows.
• Lights are placed in a fixed position based on the active reference plane, which usually is not where one will want it. To place the light, make sure it is not ghosted, and select, edit cone of vision. From here one can easily place the light, and adjust its angle.
• By double clicking on a light in the lights pallet, one can adjust the light’s intensity, and color.