As you can see, the shadows on the ground have rounded corners, my lightmap seems to be ok but maybe I’m doing it wrong (you can see it by following the link bellow)
Lightmap : http://imagizer.imageshack.us/a/img908/6490/d8WmVz.jpg
I set it to 1024 and the building quality is set to production mode.
Your lightmap resolution is too low–the setting you changed was for the automatic lightmap UV’s generation settings, not the actual lightmap resolution.
Also, with your lightmap UV’s, you could do them better, there are very thin parts there that will cause problems because they are likely to be thinner than a pixel, for better results you would want to reduce the number of seams in your UV’s and you should avoid having such small objects split off like that.
Actually I also set the genreral lightmap at 1024, I tried to replace the staticmesh with just a plan and it works better so you’re right, the problem came from the UV’s.
What do you mean by saying area light shadows ? Is it a parameter to enable or maybe some special lights to put front of each window (noob inside me) ?
Stationary lights can either use distance field shadow maps that yield hard shadows or area light shadow which yield physically based soft shadows but will need bit more light map density.
