Light Property Editor

Light Property Editor

Settings for general properties of the selected light. You can choose between Light Property parameters, which control the light attributes (shadowmaps, inclusive/exclusive, area light, etc.), or Color Result, which controls all light-shader functions (color, spread, falloff, etc.).

General

Specifies what type of light you are editing; you can define basic light characteristics.

Light Type

Displays what type of light you are working on. The Light Type can be changed at any time. Your choices are:

Infinite: Simulates light sources that are infinitely far from objects in the scene. There is no position associated with an infinite light, only a direction. All objects are lit by parallel light rays.

Spot: Casts rays in a cone, simulating a real spotlight. Useful for lighting a specific object or area.

Point: Casts rays in all directions from the position of the light. This is similar to a regular light bulb, whose light rays emanate in all directions from the bulb.

Cone Angle

Sets the angle in degrees of the cone for a spotlight only.

Exponent

Used to determine exponential light falloff. Range is from 0.01 to 10. Low values will make the light fall off more slowly than high values.

Light Contribution

Determines what type of lighting a light will project. By default, a light will produce both diffuse and specular lighting.

Specular

Projects specular light. If Diffuse is off, the light will appear harsh and brighter.

Diffuse

Projects diffused light. If Specular is off, the light will appear much softer.

Selective Light

Specifies whether the light is selective and whether the selected objects are included with or excluded from the light. Objects to be affected by a selective light are stored in the Associated Models group of a light.

Inclusive: Illuminates only those objects selected in the Associated Models list.

Exclusive: Illuminates all objects except those selected in the Associated Models list.

Shadow Map

Controls how shadows are created by a shadow map for the selected light. The Light Shadow Map page is available in the Light property editor. Shadow mapping works only with spot lights.

Use Shadow Map	Activates shadow map properties.
Resolution	Specifies the resolution (in pixels) of the computed shadow map.
Softness	Creates soft shadows by defining a penumbra area. The penumbra is the “secondary” shadow that is cast when only part of the light is blocked by the object.
Samples	Specifies the number of samples to be calculated. Soft shadows are produced by distributing samples in a region of the shadow map.
Enable Shadow Map in Region	Enables the shadow map in the render region options.
Enable Shadow Map in All Passes	Enables the shadow map in the render options of all of the render passes in the scene.

Volumic Shadow Maps

Volumic shadow maps, instead of simply storing the distance from the light to the first object hit, will raymarch through the scene from the light origin until a fully opaque object is hit. Along the way it stores the changes in color or intensity along with the depth at which the change occurred.

Volumic shadow maps are useful when rendering shadows for geometry hair.

Use Volumic Shadow Maps	Toggles volumic shadow maps.
Sub-Samples	Controls the oversampling of each pixel of the shadow map. The value specifies the size of the oversampling rectangle in N x N sub-pixels. For example, if Samples is set to 3, nine samples are taken, per shadow map pixel.
Step Size	Sets the distance between each sample taken when raymarching from the light origin.
Shadow Type	Specifies what is sampled and stored in the shadow map. Intensity Only: Only changes in intensity are stored in the shadow map, resulting in just grayscale shadows. Full Color: Changes in color are stored in the shadow map Color sampling has a higher memory overhead than just intensity sampling, but allows for full-color shadows.

Area

Contains settings that define area-light options for point and spot lights. The Area Light page is available in the Light property editor.

Area Light

Activates area-light properties for the selected light.

Visible in render

Makes the light-emitting surface visible in the render output (rendered frame, preview, render region, and so on). This is useful when you want area lights to appear in reflections.

Geometry

Sets the shape of the light source.

Rectangle: Emits rays from a rectangular area. The light icon appears with a rectangle around it.

Disc: Emits rays from a disc-shaped area. The light icon appears with a circle (disc) around it.

Sphere: Emits rays from a spherical surface. The light icon appears with a sphere around it.

Cylinder: Emits rays from an open-ended cylindrical surface, The light icon appears with a cylinder around it.

Samples

U, V

Controls the number of times the light is sampled to determine the illumination for each point in the scene. The sampling is performed in the U and V directions as specified.

Area Transformation

Scaling X, Y, Z	Sets the size of the area light. The X value corresponds to the X axis of a rectangle or the radius of discs or spheres. The Y and Z values correspond to the Y and Z axes of the rectangle.
Rotation X, Y, Z	Performs rotation relative to the light’s local coordinates in degrees. The Z axis of the local coordinates is defined by a vector from the spot light’s position to its interest’s position. If this option is not selected, rotations are performed relative to the global coordinate system. Rotation has no effect when the Geometry option is set to Sphere.

Photon

Controls indirect lighting and caustic highlights. The Photon Light page is available in the Light property editor.

To render caustics, you must also set the Caustic options for the objects that receive and transmit the effect, as well as activate caustics on the Photon page of the mental ray Render Options Property Editor and/or the Render Region Options Property Editor.

Caustics	Activates caustic lighting properties on the light.
Global Illumination	Activates global illumination properties on the light.

Energy

Color	Controls the color of light rays emitted by the light for the purpose of photon lighting calculations. Note that this parameter can be animated.
Intensity	Controls the intensity of the selected energy color.

Number of Emitted Photons

High values for these parameters will greatly increase render times.

Caustic	Controls the quality of the illumination. To easily see caustic effects, boost the value to 100 000 or higher and then tune.
Global Illumination	Controls the quality of the illumination. To easily see global illumination effects, boost the value to 100 000 or higher and then tune.

Autodesk Softimage v.7.5