DiskLight

An intrinsic light that emits light from a circular disk centered in the XY plane. The light is emitted from one side of the disk along the -Z axis.

Use DiskLights to illuminate objects, simulating soft boxes used in photography, linear lights, fluorescent lights, and light panels.

The following simple example has a DiskLight positioned near a Sphere and Cube, with a radius of 0.8 and an intensity of 20.

#usda 1.0
(
    upAxis = "Y"
)

def Scope "Lights"
{
    def DiskLight "Light1"
    {

        float inputs:radius = 0.8 

        color3f inputs:color = (1, 1, 1)
        float inputs:intensity = 20.0
        double3 xformOp:translate = (4, 0, 1)
        uniform token[] xformOpOrder = ["xformOp:translate"]
    }
}

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:radius

USD type: float

Fallback value: 0.5

Radius of the disk. A larger radius increases the overall reach of the light.

light:shaderId

USD type: token

Fallback value: DiskLight

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

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