Understanding the Different Lights in Unity

Objective: To distinguish between the 4 different lights available in Unity and provide examples for their use.

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When choosing a light option in Unity we are faced with 4 options. let’s run through them and see which would be the most applicable to your scene.

Directional Light

A light source that is infinite in a particular direction. It doesn’t have an identifiable source position or specific distance so the light itself doesn’t diminish, making all objects in the scene be illuminated equally. This gives the directional light the benefit of being able to be placed anywhere in the scene.

Directional light rotating

Watch the above gif as I rotate the directional light in a circle. Now I could have this directional light game object miles away in the scene, but the light source would remain constant.

A great example of using this would be if you wanted to use a large distance light source (such as a star) or sunlight in your scene.

Point Light

Compared to the directional light, a point light has a specific source position and emits light in all directions equally as opposed to a specific direction. This light source also has a diminished intensity the further you go away from the light source.

Point light emitting light in all directions on a surface showing diminishing light

Watch the diminishing light above as a move the light up and down near a surface.

A lamp, a fire, indoor lighting or glowing lights would be great examples for this light.

Spot Light

Similar to the point light, the spot light has a specific source point and a diminished range however, the spot light works within a particular angle. This makes it look like a cone of light being projected in a certain direction from a source point.

Point light in a corner emitting light in all directions
Spot light with Gizmo showing the cone of light and angle in a specific direction

Compared to the point light picture above the spot light has an angle that the projection stays between where as the point light emits light equally in all directions.

Examples of this could be a headlight, torchlight or car headlights.

Area Light

This type of light is defined by a rectangle in space where the light emitted is in all directions uniformly across the surface area but only on one side of the rectangle. Similar to the point and spot light, the light diminishes as it goes away from the source. This type of light is quite processive intensive and as such is not available at run time and can only be baked into lightmaps unlike the other 3.

Area light with a rectangle surface facing down

Some examples of using this type of light would be for an interior room or a streetlight.

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