This is a controversial subject which would get much attention if the physics simulation were flexible enough to allow some of the parameters of the building construction or some of the conditions of the simulation to be adjusted by users.
The WTC Tower collapses appear to violate the Law of Conservation of Momentum because, according to the National Institute of Standards and Technology (NIST), the Towers collapsed in 9 seconds and 11 seconds respectively while freefall time from the height of a Tower is 9.2 seconds. How could this occur with all that building mass in the way of the falling block of floors?
An explication of this apparent violation of physics can be read here with links to mathematics by Dr. Kenneth Kuttler:
Dr. Steven Jones et al have recently published a paper, "Fourteen Points of Agreement with Official Government Reports on the World Trade Center Destruction" in Open Civil Engineering Journal. Item #5 in the paper references the well-known violation of the law of conservation of momentum and challenges NIST to explain the discrepency.
Of course, a simple physics simulation will not end this contentious debate. A debate-ending physics simulation would take 75 man-years to program and require detailed virtual replication of the Towers. It would have to be run on a super-computer! However, a decent simple physics model which basically captures the main construction features of the WTC Towers would be useful to illustrate problems with the collapse.
In its investigation, NIST used its own computer simulations of the collapses. But they admittedly could not duplicate the actual events without a great deal of unrealistic tweaking. NIST has never released details of its computer simulations of the Tower collapses to the public.
The Towers consisted of 47 box columns in the core, 250 perimeter columns, and 110 floors. Like all skyscrapers, the mass and strength of the Towers declined with height, so that the core columns were extremely massive and strong at the base but not so heavy at the top. Detailed architectural plans of the South Tower are available at Architects and Engineers for 911 Truth (www.ae911truth.org). Richard Gage and others at ae911truth.org have been generally responsive in emails to people with questions about the Tower collapses.
In a simple physics model of the collapses, floors might be considered to "float" in air unsupported until impacted from above by the falling block of collapsing floors. Or, resistance put up by vertical core and perimeter columns might be adjusted. Mass of the falling block itself might be adjusted to reflect the fact that much of that mass was expelled outwards in the collapses and thus could not contribute to the downward crushing forces upon the intact building mass and structure below it.
The physics sim ought to be a thought-provoking visual and conceptual aid. If it reflected honest physics and were done well, it would be posted everywhere! It would probably go viral worldwide.