I have spent about a week cleaning up this model and also layouted its lightmaps by hand to get the best possible result. However, after building lighting in production quality, out comes this:
And here are the lightmap UVs I created for the castle and for the floor visible in the above screenshot
I have different charts (islands? chunks?) for the sides of the bridge and for its top to prevent shadow smear across hard edges. But somehow there’s a large patch of light on the bridge and a large patch of shadow on the ground that do not belong there.
Do notice that the problems happen in the corner of the bridge (which has quite a bit of space to any neighbors) and especially on the floor which is a completely different lightmap with one continuous UV set for the ground.
Your lightmap resolution is too low, if you see edges of the shadows that are blobby then that means it’s too low, default is too low for most things so if you didn’t change it then that’s why
