Barndoors

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 barn door flaps. Each barn door 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).


See the Light Filters page for more information on how to create and connect the Barndoor filter.


The images below, show the various attributes of the Barndoor filter. The spotlight model is purely for illustrative purposes.

Top Left

Moves the left corner of the top flap across the face of the light.

Top Right

Moves the right corner of the top flap across the face of the light.

Top Edge

Controls the edge softness of the top flap.

 

Bottom Left

Moves the left corner of the bottom flap across the face of the light.

Bottom Right

Moves the right corner of the bottom flap across the face of the light.

Bottom Edge

Controls the edge softness of the bottom flap.

Left Top

Moves the top corner of the left flap across the face of the light.


Left Bottom

Moves the bottom corner of the left flap across the face of the light.

Left Edge

Controls the edge softness of the left flap.

Right Top

Moves the top corner of the right flap across the face of the light.

Right Bottom

Moves the bottom corner of the right flap across the face of the light.

Right Edge

Controls the edge softness of the right flap.



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