"I’ll try to meet the actors one-on-one first. First of all, particularly with this going into a film where there’s two predecessors, I had to get as much information from them about what they felt about their characters to start with. I had to express all my own personal opinions first and just gather information. So, the first meetings are one-on-ones. Then the second meeting’s, again one-on-ones, combine everything they’ve said about their character with what may change and what we like for this film . . . Then, two or three more meetings, question and answering meetings, slight rehearsal meetings, discussing lines, and this is all done separate from each other. Then we come into rehearsals," Slade explained.
He went on to state that by meeting with each castmember individually in this way, he was able to know their perspectives and focus on the scenes themselves rather than the characters in question. Efficiency, it seems, resulted.
Slade also discussed how these meetings helped to shape some of the characters, especially those portrayed by Bryce Dallas Howard and Xavier Samuel. Since these two were more available, time-wise, for discussion-oriented meetings than, say, the "big three" (Robert Pattinson, Kristen Stewart, and Taylor Lautner), they were able to coordinate a great deal of character shaping in the early stages.
Full Interview, Video and Source HERE