Lights#

Lights illuminate a rendered scene. How you add them depends on the backend:

  • Rasterizer (and the viewer): lights come from the lights list on gs.options.VisOptions, using the light classes in gs.options.vis. With no configuration the scene gets a single directional light, so it is lit out of the box. Ambient fill is set separately through VisOptions.ambient_light.

  • RayTracer: there are no light objects. Lights are entities with an Emission surface, plus optional SphereLight area lights (below).

  • BatchRenderer: lights are added at runtime with scene.add_light(...); see gs.renderers.BatchRenderer.

scene = gs.Scene(
    vis_options=gs.options.VisOptions(
        lights=[
            gs.options.vis.DirectionalLight(
                dir=(-1, -1, -1),       # direction the light travels, world frame
                color=(1.0, 1.0, 1.0),  # RGB in [0, 1]
                intensity=5.0,
            ),
            gs.options.vis.PointLight(
                pos=(2.0, 0.0, 3.0),    # meters, world frame
                color=(1.0, 0.9, 0.8),
                intensity=8.0,
            ),
        ],
        ambient_light=(0.1, 0.1, 0.1),  # uniform fill so shadows are not pure black
    ),
)

For the task-oriented explanation, see Rendering.

Rasterizer lights#

These classes populate the lights list on gs.options.VisOptions and light the rasterizer and the viewer.

gs.options.vis.DirectionalLight#

A light with parallel rays and no position, like the sun. The scene’s default light is one of these.

class genesis.options.vis.DirectionalLight(*, type: Literal['directional'] = 'directional', dir: tuple[float, float, float], color: tuple[float, float, float], intensity: float) → None[source]#

gs.options.vis.PointLight#

A light that emits from a point in space, falling off with distance.

class genesis.options.vis.PointLight(*, type: Literal['point'] = 'point', pos: tuple[float, float, float], color: tuple[float, float, float], intensity: float) → None[source]#

gs.options.vis.AmbientLight#

A uniform fill light with no direction, applied everywhere so shadows are not pure black. Ambient fill can also be set directly through VisOptions.ambient_light.

class genesis.options.vis.AmbientLight(*, type: Literal['ambient'] = 'ambient', color: tuple[float, float, float], intensity: float) → None[source]#

SphereLight#

A spherical area light for the RayTracer renderer. Add one or more to a scene to illuminate it, controlling position, color, intensity, and radius. Color values are not restricted to [0, 1], so they can express HDR intensities.

class genesis.options.renderers.SphereLight(*, pos: tuple[float, float, float] = (0.0, 0.0, 10.0), color: tuple[float, float, float] = (1.0, 1.0, 1.0), intensity: float = 1.0, radius: float = 4.0) → None[source]#

Sphere light for the ray tracer.

Parameters:

  • pos (tuple of float) – Position of the light. Defaults to (0.0, 0.0, 10.0).

  • color (tuple of float) – Color of the light. Values are not restricted to [0, 1] to allow HDR lighting.

  • intensity (float) – Intensity multiplier for the light color. Defaults to 1.0.

  • radius (float) – Radius of the light sphere. Defaults to 4.0.

See also#