This General Parameters rollout is displayed for photometric lights. These controls turn a light on and off, and exclude or include objects in the scene. They also let you set the type of light distribution.
On the Modify panel, the General Parameters rollout also lets you control the light’s target object and change the light from one type to another.
The General Parameters rollout also lets you turn shadow-casting on or off for the light, and choose which type of shadow the light uses.
To turn a light on and off:
Default=on.
To have a light cast shadows:
The light will now cast shadows when you render the scene.
Left: With Spotlight distribution, the projection cone can truncate shadows.
Right: With Uniform Spherical distribution, the light casts complete shadows.
To have a light use the global settings for shadows:
When Use Global Settings is on, the other shadow controls are set to the values used by all other shadow-casting lights in the scene that have Use Global Settings set.
Changing the affected parameters for one light with Use Global Settings set, changes them for all lights with Use Global Settings set.
To set a light's shadow parameters individually:
The settings revert to the individual settings for the light.
By default, Shadow Map is the active shadow type. On the Shadow Map Parameters rollout, the default settings are: Map Bias=1; Size=512; Sample Range=4.0; Absolute Map Bias=Off.
Scene with shadow-mapped shadows
Shadows rendered using default parameter settings
To cast area shadows:
Use controls on the Area Shadows Rollout to adjust the shadow properties.
To cast advanced ray-traced shadows:
Advanced ray-traced shadows are similar to ray-traced shadows, however they provide control over antialiasing, letting you fine-tune how shadows are generated.
Use controls on the Advanced Ray-Traced Parameters Rollout to adjust the shadow properties.
To cast shadow-mapped shadows:
To cast ray-traced shadows:
Ray-traced shadows are generated by tracing the path of rays sampled from a light source. Ray-traced shadows are more accurate than shadow-mapped shadows.
To keep an object from casting shadows:
The Object Properties dialog is displayed.
Now when you render the scene, the object casts no shadows.
To make an object not receive shadows:
The Object Properties dialog is displayed.
Now when you render the scene, the object receives no shadows.
In viewports, the interactive renderer shows the effect of turning lights on or off.
When Use Global Settings is on, the shadow parameters switch over to show you what the global settings are. This data is shared by every other light of this class. When Use Global Settings is off, the shadow parameters are specific to that particular light.
Each shadow type has its particular controls:
Excluded objects still appear lit in shaded viewports. Exclusion takes effect only when you render the scene.
When you choose this option, the Distribution (Photometric File) rollout opens on the command panel.
When you choose this option, the Distribution (Spotlight) rollout opens on the command panel.
Uniform distribution, whether diffuse or spherical, has no additional settings, so these choices don’t display a special Distribution rollout.