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Hey i created those Kitchen assets in Allplan and exported them to Unreal. When looking at the images that i also put in the link everything looks set up properly. what could be the reason that those shadows/lightmaps look so bad.
i am using GPU Lightmass for baking
Try disabling the denoiser (or switching to simple firefly remover) in GPU lightmass, or simply use CPU lightmass instead.
If the issue is still there then it is most likely due to insufficient padding around your lightmap UV islands.
If the issue is still present it is caused by a long standing issue with the intel denoiser that GPU LM uses which creates high contrast splotches around UV islands.
Some amount of seams are probably unavoidable because of the fact that your meshes are supposed to be contiguous, but are not, and all have different lightmap densities.