PxrBarnLightFilter allows us to create physically accurate window barns to simulate the real set lighting with correct shadowing. Its other usage include controlling bounce lights in a large scene. In addition to the physical mode, it also provides an analytic mode.
Select a barn mode:physical (0) The barn behaves like an open window through which light falls. The falloff and blur are determined by the size of the light, the distance to the light and distance from the barn.analytic (1) The barn has a fixed projection and manual falloff controls. If possible, use Physical Barn.
When this is on, the texture projects along a direction using the orthographic projection. When it is off, the texture projects using a focal point specified by the Apex.
Shear the projection along the X axis.
Shear the projection along the Y axis.
Distance between the center of barn and the center of projection. This is only applicable when Directional is off.
Use Light Direction
If this is on, the projection direction is determined by the position of the center of the light source. Otherwise, it only follows the orientation of the cookie. WARNING: This does not work with dome and mesh lights.
Width of the inner region of the barn (X axis).
Height of the inner region of the barn (y axis).
Radius of the corners of the inner barn square.
Thickness of the edge region.
Pre BarnThe effect on the light before it reaches the barn.
Scale the width of the inner barn shape (X axis).
Scale the height of the inner barn shape (Y axis).
Additional size of the left region (-X axis)
Additional size of the right region (+X axis)
Additional size of the bottom region (-Y axis)
Additional size of the top region (+Y axis)
Additional soft size of left region (-X axis).
Additional soft size of right region (+X axis).
Additional soft size of bottom region (-Y axis).
Additional soft size of top region (+Y axis).
Controls the strength of this light filter.
Specify whether to invert the result of this light filter before it is applied.
Global Multiplier for both the diffuse and specular contribution below.
Multiplier of this light filter result for the diffuse contribution.
Multiplier of this light filter result for the specular contribution.
Distance from the barn where the density interpolation starts.
Distance from the barn where the density interpolation ends.
Density Near Val
Density multiplier where the blur interpolation starts.
Density Far Val
Density multiplier where the blur interpolation ends.
Exponent of the density interpolation.
mult: The results of all the filters are multiplied together
max: The maximum result from all filters is used.This works best for grey scale light filters.
min: The minimum result from all filters is used.This works best for grey scale light filters.
screen: Similar to the max operation, but it combines gradients in a smoother way. This works best for grey scale light.
Light filters on a light are grouped by their combine mode. Light filters in the same group are executed together and combined by the combine mode.The groups are executed in this order (max, min, screen, and then mult) and are multiplied together, which means a filter that turns things black in the mult group will zero out all other filters.