CylinderLight

An intrinsic light that emits light outwards from a cylinder. The cylinder is centered at the origin and has its major axis on the X axis. Note that the cylinder does not emit light from the flat end-caps.

Use CylinderLights to simulate tube-shaped fluorescent lights or similarly-shaped light sources, linear lights, light panels, and commercial lighting used in building interiors.

The following simple example has a CylinderLight positioned near a Sphere and Cube, with a length of 3 and a radius of 0.25. The light has been rotated and the light cone angle adjusted to limit the light spread, resulting in a thin band of light.

#usda 1.0
(
    upAxis = "Y"
)

def Scope "Lights"
{
    def CylinderLight "Light1"
    {
        float inputs:length = 3
        float inputs:radius = 0.25

        float inputs:shaping:cone:angle = 45

        color3f inputs:color = (1, 1, 1)
        float inputs:intensity = 20.0
        float3 xformOp:rotateXYZ = (0, 0, 45)
        double3 xformOp:translate = (0, 0, 1)
        uniform token[] xformOpOrder = ["xformOp:translate", "xformOp:rotateXYZ"]
    }
}

def Xform "TestGeom"
{
    def Sphere "Sphere1"
    {
        token purpose = "render"
        color3f[] primvars:displayColor = [(1, 1, 1)] (
            interpolation = "constant"
        )    
        double3 xformOp:translate = (0, 0, -2)
        uniform token[] xformOpOrder = ["xformOp:translate"]          
    }

    def Cube "Cube"
    {
        token purpose = "render"
        color3f[] primvars:displayColor = [(1, 1, 1)] (
            interpolation = "constant"
        )    
        double size = 8
        double3 xformOp:translate = (0, 0, -8)
        uniform token[] xformOpOrder = ["xformOp:translate"]          
    }
}

Example RenderMan output for this layer:

Properties

inputs:length

USD type: float

Fallback value: 1.0

The length of the cylinder in the local X axis.

inputs:radius

USD type: float

Fallback value: 0.5

The radius of the cylinder.

light:shaderId

USD type: token

Fallback value: CylinderLight

The shader ID for a CylinderLight. USD will also register a Sdr shader node with a “CylinderLight” identifier and the source type “USD” to correspond to the light’s inputs

treatAsLine

USD type: bool

Fallback value: False

This is used as a hint to renderers that this light can be treated as a “line light”, effectively a zero-radius cylinder. This is useful for renderers that support non-area lighting. Renderers that only support area lights will ignore this attribute.

Inherited Properties (Boundable)

extent

USD type: float3[]

Inherited Properties (Xformable)

xformOpOrder

USD type: token[]

Inherited Properties (Imageable)

proxyPrim

USD type: rel (relationship)

purpose

USD type: token

Fallback value: default

visibility

USD type: token

Fallback value: inherited