"packed full transform" of packed object

[CJun]

At beginning, I was trying to extract rotation information from alembic files.(those files are exported from houdini as cache for simulation) I saw some topics in the forum reading that I should look for the intrinsic attribute "packed full transform".

I checked that out and found that attribute is not changing along time. It's always a matrix with 0 and 1.

Later I tried to pack a moving object and the "packed full transform" shows exactly the same.

I attached a very simple file about the problem with packed object.

So how am I supposed to extract rotation information in that case?

Thx for any help.

 

intrinsic.hipnc

[graham]

The intrinsic transform represents a transform applied to the primitive itself, not anything to do with the geometry inside it.  In your case you are modifying the geometry which you then pack, but you are not changing the resulting primitive itself.  In your example you can see this given that the intrinsic:bounds is changing but the transform is not.

If you were to pack the geometry first and then transform it (swapping the node ordering) you would see that the packedfulltransform is updated as you modify the primitive because you are applying the transform to that packed entity, not the raw geometry inside it.

[CJun]

Ah! Thx a lot!!

I got what u mean.

For anyone who does the same thing like me, which is transform the geometry instead of the object, there is one way to get the transformation information.

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!