The Amazing Power of Light Probes

In this article, I wanted to discuss working with a new feature for improving lighting when working in Unity HDRP: Light Probes! Briefly, Light Probes are a collection of meshes that emit light onto dynamic objects based off of the closest existing light sources surrounding them.

Let’s take a look on how this applies practically as well as how to implement and work with this tool!

To begin, let’s add a Light Probe Group by navigating to the plus sign in the Hierarchy → Light → Light Probe Group.

Notice how as opposed to a singular object, light probes consist at the base level of a group constructed by 2x2x2 spheres.

The goal when setting up light probes is to create a network of lattices that cover the area of the level so that Unity can project light accordingly to light/dark areas.

To accomplish this, we need to span the probes to cover the area we are working with. The easiest way to accomplish this is to select the appropriate spheres on the existing light probe and duplicate them.

We can do this by adjust the positioning of the spheres themselves by clicking Edit Light Probes and manually adjusting them/duplicate.

Now let’s test how this works: as stated before, light probes emit light onto dynamic objects based off of the closest existing light sources surrounding them. This means we need to identify static objects as well in our scene. Here in my lab room, I have all of my room components set to static such as the walls, floors, ceiling, and struts.

Next for testing purposes, I’ll add a 3D sphere into the room. Notice what happens to its appearance when I move the sphere around in the room:

The sphere acts as a dynamic object, and when it translates within the room the closest spheres to it within the light probe “network” emit light accordingly onto the sphere based off of the lights surrounding it! We can see the probes being utilized to cast in real time in the scene view as well:

Light Probes are an extremely helpful tool to help us test lighting in areas and adjust them accordingly, especially when a player is navigating throughout a level and each section’s lighting is lit appropriately.