barndoor

Class

Shader

Output

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Synopsis

Shape of light beam controlled by a Barndoor filter connected to a spotlight

 

This light filter can only be used with spot lights. Barn doors are opaque moving panels attached to the sides of the light's opening. They are typically used in theatrical and film lighting for additional control over the shape of the light beam. This Barndoor filter introduces four barndoor flaps. Each barndoor flap has three parameters. The first two parameters position the two ends of the flap across the face of the light. The third parameter (Edge) controls the softness of the edge. The positions are distances from the respective edge. The edge softness is a ramp width. The ramp starts at one (fully-open) at the barndoor's edge and tapers off to zero based on the edge width in the direction to the perimeter of the spotlight. For example, a flap with coordinates 0.25, 0.25 and an edge of 0.125 will be perfectly "open" at 0.25, and will be perfectly "closed" at 0.375. The edge effect starts at the barndoor edge and works its way outward (*not* inward).

 

 


 

barndoor_top_left
Moves the left corner of the top flap across the face of the light.
barndoor_top_right
Moves the right corner of the top flap across the face of the light.

 

barndoor_top_edge
Controls the edge softness of the top flap.
 
barndoor_right_top
Moves the top corner of the right flap across the face of the light.
barndoor_right_bottom
Moves the bottom corner of the right flap across the face of the light.
barndoor_right_edge
Controls the edge softness of the right flap.
barndoor_bottom_left
Moves the left corner of the bottom flap across the face of the light.
barndoor_bottom_right
Moves the right corner of the bottom flap across the face of the light.
barndoor_bottom_edge
Controls the edge softness of the bottom flap.
barndoor_left_top
Moves the top corner of the left flap across the face of the light.

barndoor_left_bottom
Moves the bottom corner of the left flap across the face of the light.
barndoor_left_edge
Controls the edge softness of the left flap.
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