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SpotAngle

Opening angle of the light cone of a spot light

Value Summary

MandatoryReal-valued expression (interpreted in radians)

Graphics Primitives

ObjectsSpotAngle Default Values
plot::SpotLight 

Description

SpotAngle sets the opening angle of the light cone of a spot light in radians, and defines the opening angle of the light cone emitted by spot lights of type plot::SpotLight.

The values for SpotAngle have to be given in radians. Reasonable value lie between 0 and π.

SpotAngle can be animated.

Examples

Example 1

When creating a spot light, the third argument is the SpotAngle:

spotlight := plot::SpotLight([0, 0, 1], [0, 0, 0], a*PI, 1, 
                             a = 0..0.4, LightColor = RGB::White):
spotlight::SpotAngle

We illuminate the x-y plane by the animated spot light and some ambient light. The spot light is visualized by a cone:

ambientlight := plot::AmbientLight(0.2):
s := plot::Surface([x, y, 0], x = -1..1, y = -1..1, 
                   Submesh = [2, 2], Color = RGB::White, 
                   FillColorType = Flat):
c := plot::Cone(0, [0, 0, 1], 
                0.6*tan(a*PI/2), [0, 0, 1 - 0.6],
                a = 0..0.4, Color = RGB::Orange.[0.5]): 
plot(s, c, spotlight, ambientlight,
     CameraDirection = [-9, -18, 12])

delete spotlight, ambientlight, s, c:
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