Hi, I am trying to get the rotation information from an alembic file exported by houdini.

I found that I should go and look for an attribute called “packed full transform”. However that attribute is not changing at all.

Later I found every time I use Pack node, I can only get information of an ever-changing bounding box but never the “packed full transform”.

So is there any way to pack geometry with “packed full transform”. Or is there a way to get the rotation information from those changing bounding box information?

Thx~

Some other people told me that “packed full transform” is for object transformation instead of geometry transformation.
That's why I can't get that attribute.

Though I still don't know why geometry can rotate as I can't find any rotation information, there is a way to get the rotation information.
Select the packed geometry, unpack - use Timeshift to get the geo at first frame - use ExtractTransform, the Timeshift one into the first input and the unpacked geometry for the second input - done!

Ok…I replied myself 2 times…But later found I was using another account.

Here is the answer.

I heard from other people that the “packed full transform” is actually for object instead geometry.
I didn't get the “packed full transform” as I was applying transform animation to geometry and pack the geometry instead of the object.

Here is the solution to get transform information(rotation especially) from a packed geo. It maybe useful when u want the transform information from a cached RBD object. I use this way to replace a thick RBD, which is easy for simulation, with a thinner one(because it looks better).

Choose the packed object, unpack - use Timeshift to get the geo at first frame - use ExtractTransform, the Timeshift one into the first input and the unpacked geometry for the second input - done!

Here is the houdini file about that method.