Hello, everyone.
The problem is that some objects cast the shadows on other objects in a very weird way, something like a stairs.
But it depends on the specific objects. The other ones project normal shadows (as you can see on the left of the marked place). I think that the problem is either in the mesh of the planks floor which cast shadows
or the mesh which the shadows are casted on.
Hi!
Are the steps one single mesh or separate pieces?
Anyway: it’s almost 100% that it’s a lightmap problem! …either your lightmap resolution is not high enough to get proper results or it’s just laid down badly…
The thing is that there are not steps at all. As I stated, it is plank floor with a big number of planks which the shadows from several objects cast on in this strange way. But this floor is a single mesh.
Anyway, thank you for your reply. I hope that the problem is in this lightmap, even though I do not know what is this so far as I am just a new user. So I guess I will have a lot of fun with this 
