The Lume Beam shader creates quick-to-render atmospheric effects such as volumic light beams and halos from selected light sources in your scene. Rendering speed is achieved by eliminating shadow calculations, which means that when shadows are necessary, you are responsible for creating shadow-casting geometry for the beam's area of effect.
This shader prefers light sources with an origin, directional lights (such as infinite lights) do not work as well. Also, note that the Lume Beam shader ignores the attenuation properties of the light.
Lume Beam Options
Color
Sets the color of the virtual fog particles. The final color of the beam or halo is determined by both the color of the particles and the color of the lights themselves.
Fog Density
Adjust the “thickness” of the fog effect surrounding the light source. Larger values cause the effect to be bigger and brighter; smaller values cause the effect to be smaller and dimmer.
Light List
Specifies which lights should produce the effects.
Pick Item:Lets you pick a light in your scene that will be used to compute the effect.
1. Click the Pick Item button.
2. In the pop-up explorer, select the lights you want to use.
3. Right-click outside the explorer to end the picking session.
Remove Selected:Removes a selected light from the light list. Once removed, the light will no longer influence the effect created by the shader.
Render Tree Usage
To create a beam effect
1. Get a polygon mesh cone, for example, and place it in your scene. The size and form of the geometry determines the form of the beam.
2. Assign a fully transparent surface material to the cone.
3. Get a light source (such as a Point light) and place it at the top of the cone. Make sure that the light source’s selective property includes the cone object.
4. In the render tree, connect the Lume Beam shader to the Volume input port of the cone’s material node.
5. In the Lume Beam property editor, do the following:
- Add the light source to the shader’s Light List.
- Set the Color and Density options to tune the effect.
To create a halo effect
When you attach the Lume Beam shader to the scene (in the pass volume shader stack) the shader creates halos around the origin of point lights and spotlights. See Creating a Volume Effect in a Scene [Lights and Cameras].
