For fortnite, Epic used a system of moving mesh elements by vertex animations for their player construction. It may be of interest for technique but it does not detail implementation http://twvideo01.ubm-us.net/o1/vault/gdc2013/slides/822154Lindquist_Jonathan_The%20Inner%20Workings.pdf
Perhaps a simpler method would be to use a destructible mesh. I’m not sure how that would work or the degree of control you would have over aesthetics.