Optimize hardware ray tracing with Lumen on Android devices
Introduction
Lumen and Ray Tracing
Acceleration Structure
Only Add Important Objects into Ray Tracing
Take Full Advantage of Instancing
Optimize Acceleration Structure
Reduce Acceleration Structure Run-time Update Cost
Lumen General Setting Optimizations
Next Steps
Optimize hardware ray tracing with Lumen on Android devices
Who is this for?
This is an introductory topic for Unreal Engine developers interested in optimizing hardware ray tracing with Lumen on android devices.
What will you learn?
Upon completion of this Learning Path, you will be able to:
- Learn about ray tracing.
- Understand what an acceleration structure is.
- Learn about the best practices for getting the maximum performance of hardware ray tracing on Lumen for Arm devices.
Prerequisites
Before starting, you will need the following:
- A computer capable of running Unreal Engine 5.3 or later version .
- An Android mobile device that has a Mali GPU with hardware ray tracing support.
- A USB cable to connect the mobile device to your computer.
Summary
This summary was drafted with an approved AI-assisted workflow and reviewed by Arm contributors before publication. Human technical review remains part of the process so the final page reflects engineering rigor, accuracy, and Arm editorial standards.
You’ll improve Lumen hardware ray tracing on Android devices with Arm Mali-based GPUs by refining acceleration-structure contents and organization. First, you’ll choose which actors to include and exclude small contributors. Then, you’ll inspect instancing with Unreal’s Ray Tracing Debug picker, and convert repeated objects to instanced actors. Finally, you’ll check Instance Overlap to reduce traversal work while preserving the intended lighting.
Frequently asked questions
These FAQs were drafted with an approved AI-assisted workflow and reviewed by Arm contributors before publication. Human technical review remains part of the process so the final page reflects engineering rigor, accuracy, and Arm editorial standards.
Enable hardware ray tracing for Lumen on the target Android device as referenced in the prerequisite guidance. Open the Unreal Engine project and the level you plan to optimize.
Use the actor details panel and turn off ray tracing visibility for objects that do not affect lighting or are very small. Preview the scene to confirm that lighting quality remains acceptable.
Run the command
r.RayTracing.Debug.PickerDomain 1 to set the picker to instance mode, then use Ray Tracing Debug and select Picker. Click scene elements to inspect their instancing status and convert repeated objects to instanced actors when possible.Open the Instance Overlap view under Ray Tracing Debug and look for areas showing high overlap. Adjust meshes and actor bounds so each bounding box contains minimal empty space and overlaps less with neighbors.
You reduce hit tests because the acceleration structure stores scene geometry in a hierarchy. Fewer, less-overlapping bounds lower traversal work, which can improve hardware ray tracing efficiency.