Reflection Probes vs. Screen Space Reflections in Unity

Simon Leen
3 min readJul 19, 2021

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Objective: Compare Reflection Probes to Screen Space Reflections

Reflections like lighting are a very important visual aspect when it comes to 3D gaming. With unity we use one of two types of reflections.

  1. Reflection Probes

These sample our envoirnment and create reflections around us. It them takes and converts the data and stores it in a cubemap. These reflections do work but are a cheaper substitute in that they cost less on the resources side but still some form of reflections are better than none. They are better suited to mobile games where screen size is smaller and resources are limited.

To create a reflection probe, right-click in the hierarchy, go to light and then reflection probe.

The box in the first image above, shows the newly created reflection probe and its size. The second image shows that the reflection probe is already creating a sample of the envoirnment. You can extend the size of the probe by editing the bounding volume by clicking on it in the inspector then stretching the dimensions in the scene using the focal points.

Once you have set the dimensions for the probe you can adjust the settings such as intensity in the inspector.

You can see from the difference between the above images the variations of reflection without and with the probe.

2. Screen Space Reflections

The second option for reflections and by far the better option for a more immersive and overall visually pleasing experience. Screen Space Reflections do cost more resource wise but it is definetly resource usage well spent. They are implemented using a Post Processing Volume. To add it to the project first add the Post-Processing to your project by going to Window, Package Manager then installing the Post-Processing. Once installed you can add the Post-Processing to the main camera and add your effects such as the Screen Space Reflections. Again this is a more resource intensive version so it is more suited to PC or more powerful devices but if it makes sense to use it, it is the better option.

In the above images you can see the difference between before and after the Post-Processing has been applied.

In the above images you can compare directly the difference between a Reflection Probe and the Post-Processing Volume with Screen Space Reflections.

In the next post, we will move into Cinematography and start working on our first Cutscene.

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