Movable Rect Light that lightmass takes the height and width into account at runtime

I want to move rect lights & objects , snap the objects whose reflection and shadow are accurately affected by rect light.
( It doesn’t matter that snapping time is taken. Because the target is not game but simulation)

So could you tell me how to make the movable Rect Light that Lightmass takes the width and height of the light into account.
According to document, the default movable rect light emits like spot light.