https://gumroad.com/l/hops_shirt
In this video I use Blender 2.79 with KitOps/HardOps/Boxcutter to create an animated insert in Blender.
http://kit-ops.com/
KitOps is available in both paid and free variants.
More information about Boxcutter and Hard Ops here.
https://masterxeon1001.com/2018/09/25/boxcutter-6-9-0-poly-dirk/
https://gumroad.com/l/BoxCutter
https://masterxeon1001.com/2018/09/25/hard-ops-0096-proxium/
https://gumroad.com/l/hardops
