Reflections in Pixotope

Reflections are a complex subject in 3D rendering, and they become even more challenging in Virtual Production.

TLDR

We recommend using Lumen for reflections. Learn more about Lumen Compositing in Pixotope

General objectives

For virtual objects

Cast shadows onto the real world, simulating occlusion of real light
Reflect onto the real world, mimicking reflections on real-world reflective surfaces

For real objects

Reflect onto virtual objects
(Optional) Cast shadows onto virtual objects

In reality, there's a feedback loop between shadows and reflections in the real and virtual world. We usually don't attempt to model this with perfect accuracy.

The Challenge

We're working with Unreal Engine, a game engine not originally designed for Virtual Production. It expects to have access to the exact locations and properties of everything in its scene.

Reflection/Shadow technologies

We need to handle

Screen space reflections
Screen space ambient occlusion
Planar reflections
Lumen Reflections/Shadows/GI

Options for reflections

Lumen (recommended)

In Unreal Engine 5.x, Lumen is being pushed strongly as the future of light/shadow/reflection compositing. For that reason we are focusing our efforts on making the support for Lumen in Pixotope as good as it can be doing virtual production.

Learn more about Lumen Compositing in Pixotope

Planar reflections

An option if you're willing to trade performance
Can mitigate certain artifacts that appear with Lumen

To use

Change the Reflections Method to "None" on the PostProcessHandler
Add a Planar Reflection from the Place Actors > Visual Effects panel

For proper use between AR and XR, the planar reflection needs to be in the same level as the holdout objects and included in the hidden list of the planar actor.

Screen space reflections

Lower quality, better performance

To use

Change the Reflections Method to "Screen Space" on the PostProcessHandler

Standalone ray tracing

Deprecated by Epic
If you're using UE 5.3 or older, we recommend Lumen instead
For versions newer than 5.3, this option is not available