Looks like it’s in the position where 450 11th Avenue is. My assumption is based upon the position of the 7 train ventilation building across the street from that proposal and in front of it is the Javits Center. That lot is currently half-occupied by 450 11th Avenue. A comment on the NY Yimby Article also points out this assumption as well.
The first rendering shows it between 37th and 38th Street on 11th Ave, although the second shot looks more like 450 11th Ave where the Aloft Hotel is currently being built.
