Hello ! So I made a simple test level where I just change the opacity of some object material with a press of a button. But when the object disappears, its shadow stays on the level until I turn the camera around. When I turn the camera the shadows get cleaned up. I tried the same test on Unreal 4…

This is due to Virtual Shadow Maps. Shadow data is cached, and only updated when certain events invalidate the cache. If the cache is not invalidated by the material change along, you will need to force an invalidation somehow. This may require changing the objects mobility if it is set to static. …

Unreal 5 Material Runtime Opacity problem with Shadows

Development Rendering

BlackFlicka (BlackFlicka) November 15, 2023, 7:00pm 4

Thank you ! Disabling the VSM worked !