BlendLuxCore LightPanel

Header

The available light types are:

• Point
• Sun
• Spot
• Hemi
• Area

Point

See also: Blender manual.

Power/Efficacy

Radius: Defines the size of the point lamp. If greater than zero, the point lamp is a sphere, but only in shadow and reflection calculations. It can not be viewed directly, so it will always be invisible to direct camera rays. A higher radius leads to softer shadows.

IES File

Image: Projected spherically. If black/white, it can be used similarly to an IES file to drive the emitted light distribution. If the image is colored, the point light acts like a spherical projector.

Sun

Emits parallel light rays, so the position of the sun in the scene does not matter - only the rotation matters.

If you are using a sky lamp for your world, you should link the sun to the sky. This is a convenience mechanism and allows to set the gain, rotation and turbidity of both sun and sky simultaneously.

Sun type: "Sun" or "Distant".

• Sun: Simulates a physical sun, as viewed through the earth's atmosphere.
• Distant: Simulates a light source that is infinitely far a way, but does not simulate interaction with an atmosphere. Can be used to simulate a near star in space when rendering science-fiction scenes.

Relative Size: todo

Turbidity: "Foggyness" of the atmosphere. A low turbidity value simulates a day with very clear air, while a high turbidity value simulates a high amount of fog/particles/dust/smog in the air.

Spot

See also: Blender manual.

Power/Efficacy

Spot Size: todo

Spot Blend: todo

Image: todo

Hemi

This is an alternative environment light which can be used instead of the HDRI light type in the world settings. The only difference is that it allows to rotate the HDRI around any axis, not only the z-axis.

Image: Usually you want to use a HDR image here (extension ".hdr" or ".exr"). Some places where you can get them are linked here. You can also use normal LDR (low-dynamic range) images (".jpg", ".png" etc.) but they will light your scene very uniformly and won't create strong shadows and highlights.

The image should use the latlong mapping (latitude-longitude). For an example see the image below. (It is the same mapping produced by LuxCoreRender's panoramic camera)

Gamma: Should be set to the gamma of the image. HDR images are usually saved with gamma 1.0, while most LDR images are usually saved with gamma 2.2.

Sample Upper Hemisphere Only: Enable this option if you are using a ground with shadow catcher material in the scene. This option will prevent shadows being cast from below, which would lead to incorrect shadow catcher appearance.

Area

See also: Blender manual.

Note that LuxCore has a more convenient feature than portals: the Visibility Map, which is enabled by default and does not require manual placing of portal lamps.

Power/Efficacy

Visible to Camera: todo

Spread Angle: todo

Shape: todo

Size: todo

IES File

Laser: todo

Power/Efficacy

(Only visible when light type is point, spot or area)

Power: todo

Efficacy: todo

IES File

todo

Performance

Importance: How much processing power to spend on this light source compared to other light sources. Used to scale the light importance computed by the light strategy. For instance, if you set a uniform light strategy, a light with a user importance of 2.0 will be sampled 2 times more often than one with 1.0. If you use a power light strategy, the user importance will be multiplied by the light power.

When you manually set the importance, you usually also want to set the light strategy to uniform (so you have full control on how the lights are sampled).

Build Visibility Map: If enabled, the visibility map for the world light source is computed at the start of a final render (not in viewport).

Visibility

(Only visible when sun or hemi type is selected)

Here you can enable/disable the visibility of the world background to the three light bounce types. This setting is not supported by the Bidir engine as of v2.0alpha7.

• Diffuse rays include for example the matte material, the matte base of the glossy material, the matte translucent material etc.
• Glossy rays include any "non-sharp" specular reflections/transmissions with a roughness setting, e.g. glossy coating, metal, rough glass etc.
• Specular rays include any "sharp" specular reflection/transmission without a roughness setting (glass and mirror materials)