The Amazing Power of Light Probes- Game Dev Series 166

S.J. Jason Liu
4 min readJun 12, 2022

Objective: feeling the power of light probes group in HDRP.

We have had introduced (or said quick peek) of light probes group in the section of creating 3D game scene for the first time. It is quite unique and handy tool in Unity that allows you to create a gorgeous 3D game scene with light setting.
In HDRP, light probes still a powerful tool that can bring beautiful light setting/reflection into your high-definition game scene.

In this article, I would do a quick introduction of using light probes in HDRP game scene and shows how it affect to both static and dynamic objects.

Adding light probe group

Before adding light probe group, let’s make sure the basic setting of lighting in our game scene.
The default light mode would be Realtime when added into game scene at the first time. This is quite dull when lighting on objects.

First thing is changing all the mode(especially those light on fixed objects, such as walls, arch, or ceiling) from realtime to mixed. Baked would be great too, but mixed would be more flexible.

Then we can add a light probe group into hierarchy.

Go to Inspector, click the edit button of light probe group to rearrange all the probes to spread out all over the game scene.

We can use Ctrl+D to duplicate selected probes, then relocate them.

Once done, you might get the same view of your game scene as mine.

Static and dynamic

The effects of using light probe group is reflecting the light of area on dynamic objects. To do so, we need to assign all the static objects to static in Unity, then the lighting system would recalculate all the reflection in game scene.

I’ve added a sphere which means a dynamic object in scene. Take a look at the reflection on it when there is no static object in scene with light probe group.

There is nearly no other color except light reflected on the surface of sphere. This is not the right effect we want.

Assign all the static objects to Static in Unity, and let the lighting baking automatically.

Don’t forget to change the setting to Auto Generate to get a real time effect present.

Check all the static objects to Static.

Once all done and finished baking. Let’s dragging the sphere to move again in game scene.

Did you see the difference? Now the color of test tube had successfully reflecting on sphere.

Turn on Gizmo and take a look at how light probe group affect the sphere.

Dynamic object would be calculated the light reflection based on light probes.

Which means the more light probes you duplicated in game scene, the more details would be presented onto dynamic objects.

With light probes, now the color of environment light become more realistic on objects.

See how beautiful the contrast of dark side from color of floor and the bright side from the reflection of test tube.



S.J. Jason Liu

A passionate gamer whose goal is to work in video game development.