[UE 5.6] Scene Capture 2D exports black PNG despite correct render target preview

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1

My Scene Capture 2D Component exports completely black PNG files, even though the render target displays correctly in the editor.

Setup:

  • Engine Version: UE 5.6
  • Project: Fresh project using default “Open World” level
  • Render Target: RGBA8 format (changed from RGBA16f)
  • Scene Capture Component:
    • Capture Source: LDR (changed from HDR)
    • Primitive Render Mode: Render Scene Primitives (Legacy)
    • Show Flags: Default

All implementation done within PIE via Blueprint:

capture() function:
1. Capture Scene (CaptureComponent2D)
2. Export Render Target → Save as PNG

Issue:

  • :white_check_mark: Render target preview shows the scene correctly in editor
  • :cross_mark: Exported PNG is completely black
  • This identical setup worked in UE 5.5

What I’ve Tried:

  • Adding delays between capture and export
  • Executing from different contexts (Editor call, BeginPlay)
  • Confirming scene has proper lighting
  • Testing with both synchronous and delayed execution

Question: Has anyone else encountered this in 5.6? Were there any changes to the render target export pipeline or color space handling? The fact that I need RGBA8 + LDR (instead of the defaults) suggests a potential gamma/color space issue.

Any insights would be greatly appreciated!

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2

Further testing has revealed that if I change the render target format on my render target from “RTF RBGA8” to “RTF RG8” I do get a valid .png image written to disk that I can view but it does not contain the blue channel which causes it to appear discolored.

I think this suggests something wrong with the alpha channel but I am not completely sure if this is the issue or how to debug it at this time.

3

Just tried testing in a new project and it works fine for me. RBGA8 render target looks fine in editor and the resulting PNG matches when I export it via Blueprints and via right-click menu.

What happens when you export it from the Content Browser? Just want to remove gameplay and Blueprints from the equation.

What size is the resulting black PNG, and have you tried to evaluate it in something like Photoshop? A few kB would mean pure black with no data. Many kB might mean alpha channel is just 0.

4

Stephen thank you for testing this out. I think I found the issue. In UE 5.6 the alpha output setting is set to true by default. In previous engine versions this was set to false by default. In my project if I set alpha output to false I do get a valid PNG exported to disk that I can view.

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