Why does my Distance Field Ambient Occlusion lag behind a mesh when the camera moves?

Development Programming & Scripting
1

Hi, I have attached a short video of a problem I have encountered with Distance Field Ambient Occlusion. Whenever the camera moves, little squares of shadow are left behind the object, but quickly disappear. Also, the surface of the object itself gets chunky, splotchy shadowing when it comes into view, it then partially fades away, then stops and stays horrible until the camera is jiggled around slightly, or, weirdly enough, the mouse cursor is waved all over the portion of the screen where the problem is occurring.

This video shows the problem pretty well:

In the video I show the mesh distance field view, and the distance field ambient occlusion view.
https://www.youtube.com/watch?v=kS4_DzLLHAY&feature=youtu.be

Thanks to everyone for taking a look!

2

This is one of the drawbacks of using dfao, the reason it ‘stays’ is because UE4 ‘stops’ rendering the viewport unless you have “realtime preview” enabled, depending on how you design and set up your world these artefacts will be either very noticeable or almost imperceptible but they will sadly be there because DFAO is an effect that’s applied over several frames.

The way you can fix this is to turn dfao shadow casting off on movable objects and only enable it on movable ones but this entirely depends on your use cases