The BD angle adopted during an approach by a nucleophile to a trigonal unsaturated electrophile depends primarily on the molecular orbital (MO) shapes and occupancies of the unsaturated carbon center (e.g., carbonyl center), and only secondarily on the molecular orbitals of the nucleophile.
The orientation of a nucleophile's approach to a trigonal unsaturated electrophile is primarily dictated by the electronic structure of the central carbon atom, including its molecular orbital configurations and occupancies, with the nucleophile's own orbitals playing a secondary role in this process.