Hello @GarryP and thanks for your answer.
I want to achieve a nice shadow standing behind the green one.
My problem is, that the green edges, you can see pixels. I want it to be flat or sharp and not like stairs.
Secons point to clear out is that the pink one is not a real shadow, at the corners of the green you can see first blue and then pink. You cannot see another edge which would be there if its 3D. I dont know how to describe it better.
Thank you
maybe this is a refernce. At the edges you cant see staris, they are sharp
and the "shadow" is really a shadow and connected with a edge from the corners starting.