A Spot Light emits light from a single point in a cone shape in a specific direction. Spot Lights are useful for simulating light from objects such as lamp posts and flashlights. By changing the Inner Cone Angle and Outer Cone Angle you can modify the shape of the light.
|Radius||Light range (in world units).|
|Source Radius||Light build source radius (in world units).|
|Fall Off Exponent||Controls the radial falloff of a light. Works only if option the Use Inverse Squared Falloff is disabled.|
|Use Inverse Squared Falloff||If checked, physically based inverse squared distance falloff will be used.|
|Color||Light emission color.|
|Brightness||Light brightness parameter. Controls intensity of the light emitted by this actor.|
|Inner Cone Angle||Light inner cone angle (in degrees).|
|Outer Cone Angle||Light outer cone angle (in degrees).|
|View Distance||Controls light visibility range. The distance at which the light becomes completely faded. Use a value of 0 to always draw a light.|
|Minimum Roughness||Controls the minimum roughness value used to clamp material surface roughness during shading. Can help with softening specular highlights.|
By using the Source Radius property you can change the spot light source build dimensions. This allows simulating area lights and brings more realism into the scenes.
Light Fall Off
Flax offers two modes for light fall off. A custom Exponent parameter can be used or use the Inverse Squared Falloff mode. Inverse squared mode gives a more physically based distance falloff, where Radius is only clamping the light's contribution. Hovewer using the manual light falloff exponent gives more customization options.
|Mode||Describes how a visual element casts shadows. Possible options:
|Sharpness||Controls shadows sharpness. Can be used to tweak the penumbra width.|
|Strength||Controls dynamic shadow blending strength. Default is 1 for fully opaque shadows, a value of 0 disables shadows.|
|Distance||Shadow rendering distance (in world units).|
|Fade Distance||Shadow fade off distance (in world units).|
|Depth Bias||Controls dynamic shadow depth bias value. Depth bias used for shadow map comparison.|
|Normal Offset Scale||Controls dynamic shadows normal vector offset scale. A factor specifying the offset to add to the calculated shadow map depth with respect to the surface normal.|
|Contact Shadows Length||The length of the rays for contact shadows computed via screen-space tracing. Set this to values higher than 0 to enable screen-space shadow rendering for this light. This improves the shadowing details. Actual ray distance is based on the pixel distance from the camera.|
To learn more about shadows in Flax see this page.
Volumetric Fog Properties
|Scattering Intensity||Controls how much this light will contribute to the Volumetric Fog. When set to 0, there is no contribution.|
|Cast Shadow||If checked, light will cast a volumetric shadow to Volumetric Fog. Also shadow casting by this light should be enabled in order to make it cast volumetric fog shadows.|
To learn more about Volumetric Fog effect see this page.
IES Profile Properties
|IES Texture||Assigned IES texture (light profiles from real world measured data). Learn more about it here.|
|Use IES Brightness||If checked, light brightness will be based on imported IES Profile brightness. Then use the Brightness Scale parameter to scale it.|
|Brightness Scale||Custom scale parameter for light brightness if the option Use IES Brightness is checked.|
To learn more about IES Light Profiles see this page.