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USD / 3DAdvanced

uSphereLight

Sphere USD light

Adds a sphere light source to a USD scene with color, exposure, response, falloff, shadow and transform controls.

uSphereLight
DaVinci Resolve · Fusion

uSphereLight is a USD scene light shaped as a sphere. It controls direct illumination and specular response inside the stage, making it useful for physically understandable lighting, reflections and shadow design before uRenderer.

Overview

What uSphereLight does

uSphereLight is a USD scene light shaped as a sphere. It controls direct illumination and specular response inside the stage, making it useful for physically understandable lighting, reflections and shadow design before uRenderer.

Mental model

Think of uSphereLight as a real sphere lamp placed in the USD scene: size and shape define the character of highlights and shadows, while intensity, exposure and falloff define its energy.

Common uses

Add sphere lighting to a USD shot
Shape diffuse illumination and specular reflections
Create controlled shadows
Balance intensity with exposure
Build studio-style USD lighting rigs

Flow anatomy

Inputs & outputs

The port structure shows how this node fits into a Fusion graph.

SceneInput

3D scene or object data to be processed or combined.

uSphereLight
Fusion node

SceneOutput

Updated USD/3D stage for further composition, rendering or export.

Inspector

Important parameters

Start with these controls before reaching for more complicated workarounds.

Color / Red / Green / Blue

Sets the RGB color emitted by the Sphere Light.

Use channel-specific controls when the operation should not affect all components equally.

Intensity

Sets the base energy of the light.

Exposure

Changes light energy in photographic stops.

Enable Color Temperature

Enables black-body color-temperature control for the Sphere Light.

Diffuse Response

Sets how strongly the Sphere Light contributes to diffuse shading.

Specular Response

Sets how strongly the Sphere Light contributes to specular reflections.

Decay Type

Selects the light falloff model.

Chooses how light intensity falls off with distance.

Decay Rate

Sets how quickly the light falls off with distance.

Normalize Intensity

Helps maintain consistent output while the radius changes.

Radius

Sets the physical radius of the spherical emitter.

Enable Shadows

Turns shadow generation on or off.

Shadow Color / Red / Green / Blue

Sets the RGB tint of Sphere Light shadows.

Use channel-specific controls when the operation should not affect all components equally.

Density

Sets the density of generated or distributed elements.

Softness

Softens the transition at the edge of the mask, matte or effect.

Softness Quality

Sets the processing quality for this operation.

Use a lighter setting while building the comp if needed, then verify the final-quality result before render.

Shadow Map Size

Sets the resolution of the shadow map.

Higher values can sharpen shadow detail but increase render cost.

Shadow Map Bias

Offsets shadow depth comparison to reduce self-shadowing artifacts.

Use the smallest value that removes acne or detached-looking shadows.

Shadow Map Offset

Sets the Shadow Map Offset.

Translation X / Y / Z

Sets translation on the X, Y and Z axes.

Pivot X / Y / Z

Sets the pivot position on the X, Y and Z axes.

Use Target

Orients the object, light or camera toward a target point.

Use Target is convenient for aim-at rigs because the orientation follows the target as either element moves.

Export as Separate Stage

Outputs this operation as a separate USD stage instead of folding it into the incoming stage.

Practical setup

A reliable workflow

  1. 1

    Connect or create the USD stage.

  2. 2

    Add uSphereLight and position it relative to the subject.

  3. 3

    Set color, intensity and exposure before fine-tuning material response.

  4. 4

    Choose decay behavior that fits the shot scale.

  5. 5

    Adjust the shape-specific size controls for highlight and shadow character.

  6. 6

    Enable shadows and tune softness only after the lighting direction is correct.

  7. 7

    Render through uRenderer and judge the result on the final material.

Typical node chain
USD Scene
uSphereLight
uRenderer

Examples

Where this node fits in real work

Sphere key light

Use uSphereLight as the main shaped source in a simple USD lighting rig.

uShape / uLoaderuSphereLightuCamerauRenderer

Material highlight test

Use the source to evaluate roughness and reflective response.

uMaterialuSphereLightuRenderer

Troubleshooting

Common mistakes

Compensating for poor placement with extreme intensity.
Judging the light without checking the target material roughness.
Enabling expensive shadows before the basic direction and exposure are established.

Production notes

Practical tips

Use exposure for large energy changes and intensity for fine adjustments.
Evaluate diffuse and specular response separately when matching a reference.
Keep lights on clearly named USD branches in larger scenes.

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