THese graphics show that there are at least 2 general ways to view inward bowing:
1) As a pulling in from sagging long span trusses (NIST)
2) As a downward displacement of the 1000 row core columns or others.
In the case of WTC2 we can see a part of the perimeter across from the 1000 row core columns on the north face pulling inward along with the IB during the earliest moments of the visible collapse initiation sequence:
[qimg]http://img850.imageshack.us/img850/9506/cazz47pull.gif[/qimg]
It would seem pretty absurd to suggest that the famous sagging of long span trusses moved to the north face across the short truss span at that moment.
A dropping of the 1000 row columns would cause pulling in on both faces as witnessed.
Furthermore, even the NIST noticed the crimping of the roofline during the tilting and fall shown
here
[qimg]http://img690.imageshack.us/img690/2047/kinkoutrigger.gif[/qimg]
[qimg]http://img218.imageshack.us/img218/8224/kink02b.jpg[/qimg]
Before the knee-jerk denial and insults please note that Uncle NIST saw the kinking also so this is a "peer reviewed" feature.
Dropped east side core matches all observables much better than sagging long span trusses like the NIST claims.
All included in the OP of the thread that was removed. Did anyone really read the contents???