Any ideas on how they did this?

[Andrei Ionut apopei]

For me seems to be designed in Trapcode Suite

https://rdrs.uaic.ro/andrei.apopei

[Joseph W. bourke]

First two seconds are most definitely 3D Stroke, then the “fibers” could have been done in Particular, Form, or MIR, or even a 3D package.

Joe Bourke
Owner/Creative Director
Bourke Media
http://www.bourkemedia.com

[Tim Monaghan]

Guys, thanks! My first reaction was also 3D stroke, but those fibers are interesting.