The after image didnt open for me.
But probably the problem is that the shadow information in the lightmap bleeds out to other faces.
That happens when the gap between the uv islands is too small.
You have 2 solutions:
- Increase the gap betweern the uv islands in your uv. Then reimport that mesh in unreal and use that uv for lightmap calculations (dont let unreal create a lightmap uv at import)
- Increase the lightmap resolution. This one should be used with caution because it affects performance.
You can use a combination of the two methods, until you get a good result.
But, as i have some experience with that, you may get some shadow bleed from time to time.
When you get all the scene together, with normal maps and occlusion, its hard to notice the shadow bleed .