Why do I have errors with my shadows?

i made a building, when i build the light ,the shadow is error!

is there anyone know why ?

Hey assassinzxw,

Make sure the light map resolution of your meshes is a high enough value for your lights to cast accurate shadows. Here is some more in depth documentation on how lightmaps work as well as ways to optimize them. These can affect the quality of your shadows. Be sure the lights in your levels are also casting shadows and not having any sort of problems with dominance issues. If, after messing with the values of your light components, and you are still not seeing an improvement please let us know so we can investigate this further. Try reading this documentation on lightmaps to get a better understanding of how shadows are cast in your scene.

Thank you

Andrew Hurley