does enybody knows if is possible to copy from autocad dwg (a view or
something) and paste in inventor .I mean in a drawing sketch from
inventor but like a block , because i want to insert  in a drawing
view a sketch from autocad . I did but my sketch lost all constrains
and if i wanted to constrain what I imported it was really hard because
there were only lines without any connection.My only solution was to
move entire entity but it took me a lot of time because my computer
worked very hard.

I think you can.  All you have to do is download into an .ipt file.  Go to Insert- then import. dwg