I’m trying to use the Geographically Accurate Sun Positioning, which is an early access function from 4.21, to animate the Sun’s position in a whole day.
My method is using a blueprint to change the time by adding seconds, as the method in the documentation page. https://docs.unrealengine.com/en-us/Engine/Rendering/LightingAndShadows/SunPositioner
The issue is while the sun angle is changing, I can see obvious shaking of the shadow edge, and sometimes wired shadow appears on my curtain beside the window, flashing. But when I manually rotate the directional light, the shadow is sharp enough with no shaking.