The video appears to be from the LSDYNA NIST Model of the WTC 7 collapse.
From the NIST website itself, we have the link to this video, which I have linked to the time in which a very similar simulation appears.
The video is also available from Wikimedia Commons, where the entire video, in its parts, are available to view. While the original sources from the bottom of the Wikimedia Commons page appear to now be down, they all link back to NIST websites.
Youtuber Mick West appears to have the actual LSDYNA model in his Youtube video Some Problems with the UAF/Hulsey/AE911Truth WTC7 Draft Report. He even addresses the issue with the deformation seen in the LSDYNA model.
You also see this deformation here, which you don't see in reality. A lot of people point to that as being a problem, but really that's just kind of indicative of the complex nature, the chaotic nature essentially of simulations like this. Once you've gone past the initial point, the actual outcome can vary quite a lot.