any ideas on how to achieve this in houdini?

[dyei nightmare]

[Atom]

This is often done by setting up a rig, a bone for each triangle. Then you can scale the bone to 0 to keep it from appearing until the right time.

 

Scale bone to zero then increase scale as you rotate the bone to it's flat landing value.

 

The AE tuts tutorial just uses careful placement of the anchor point which would be considered the centroid or pivot in Houdini.

 

I have messed around with unfolding and it is a lot of tedious work for very little "wow", IMHO. But if your project requires it charge extra hours. Like double what you think it will take.

[gui]

perhaps you can think of it as each triangle as one single agent or particle, and set up an copy stamp system to rotate each piece in the correct time. I think the first problem would be building something like a parent system for each particle (point). You could place each point by hand, as you would with bones...

 

don´t know if this way would take more or less time, but if can make it more procedural than with bones.

[mestela]

Pretty thorough tutorial (with example hips):

 

[dyei nightmare]

...

Edited September 11, 2015 by dyei nightmare

[dedeks3000]

The AE version (from the same site):

 

 

Maybe with some transform and visibilty  nodes and  grouping with  bounding box (for the mask stuff)  , it's possible to achieve the same effect.