Unreal Movie Render Passes Stretched Images with No Alpha

omarB_14
Wed, 03 Dec 2025 15:55:54 +0000
Programming & Scripting

I am developing a tool that takes user selected actors of a level sequence, sets up a Movie Render Graph Config to render the actors as individual layers using the Alpha Holdout, and attaches a Burn-out above and below the render (making the resolution go from the standard 2048x1433 to 2048x1537, to give enough space for the burn in to display):

I’ve accomplished the layered actors rendering goal, and now I am pushing to do Render passes (like Base Color, Specular, Lighting, etc…) and from what I’ve looked into, you can do this by going to the Movie Graph Deferred Render Pass Node of your Movie Render Graph Config and add the Post Process Materials yourself:

And it does work; I get the rendered passes on whatever Post Process Materials I enable within the Deferred Rendering Node. However the Message Log returns the following warning for every frame:
’Additional Post Process Materials’ do not support ‘Aspect Ratio Constraint’ or ‘Screen Percentage’. The resulting data has been resized to match which may result in a stretched/squashed image.
And yes, the image gets stretched as if trying to compensate for the empty space that is left for the burn in:

On top of that, I cannot view the resulting Base Color Pass Render as a transparent alpha, because the deferred pass seems to write ALL the info into the Alpha Channel, so I cannot interpret transparency and the black background will always be part of the image, which is what I don’t want. (The black is not caused because of the Base Color Pass, I tested out a regular actor holdout render with a Base Color Post Process Material on the scene’s PPV, and the Alpha Holdout seems to function like normal)

The easy fix for the stretching is to remove the extended Burn-in, but:

1. I still want the burn in space on the render passes, and

2. That still wouldn’t solve the transparency issues.

So currently I am considering creating a Custom Render Pass Blueprint(maybe in C++) that will render the Beauty pass along with the other passes I’ve assigned, full with alpha transparency and Aspect Ratio Constraints to leave room for the burn-in on the top and bottom. (as I plan to composite them over the footage with already rendered burn-in) The problem is that I have no idea what to look into to start, let alone how is this all going to integrate with my Movie Render Graph Config. The best I conclusion I’ve encountered is to take the Utility Blueprint Tool where I assign my graph to the appropriate Render Execution Object, then get the Configuration (returns a Movie Pipeline Executor Job) and add my Custom Setting to it, but I don’t know what does that mean for my Movie Render Graph Config that I assigned earlier, will it be overwritten, ignored, would I have to rework my entire layered actor tool?

This is where I am stuck at, and ultimately I am just looking for some direction for what to do from here. Is there anyone familiar creating Render Passes or Scene Capturing tools who I could get advice from?

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