Lumen is the Default global illumination method for Unreal Engine and does an amazing job at creating a physically accurate looking render while keeping render times incredibly low.
Seams can occur however and the tips below should help you remove them in most cases.
If seams are completely unavoidable then an alternative is to render with Path-Tracing but we strongly advise to use Lumen where possible as it is faster and visually more impressive.
Local Exposure Seams
- Add a console variable Setting to your Movie Render Queue Settings:
- Use the Console Variable ‘r.LocalExposure’ and set the value to 0:
- With Local Exposure turned off you may start to see underexposed shadows. This can be fixed using the Shadows Gain in the OWL360Cam Post Process Section.
Turning Off Screen Traces
- Turning Screen Traces off fixes a lot of interior seams caused by bounce lighting.
- Find the Post Process Volume in your scene, search for Screen Traces, then Untick the checkbox:
- You may notice some of the Global Illumination is lost by doing this and your image will have a more stark contrast.
Meshes causing seams due to Indirect Lighting
- Sometimes meshes can cause seams due to indirect lighting.
- The meshes can be removed from Lumen Scene using by using the Mesh's Details panel to disable one of the following:
- For Software Ray Tracing, unchecking the box for Affect Distance Field Lighting.
- For Hardware Ray Tracing, unchecking the box for Visible in Ray Tracing.
Using Temporal Anti-Aliasing to Reduce Seams and Improve Global Illumination
- In moving imagery it can be useful to add temporal anti aliasing samples to remove seams and improve shadows and reflections.
- Here is an comparison of 8 temporal samples with no anti aliasing.
