Hi all
Im having a big confusion about packed primitive. Lets say I have an animated and packed sphere. when I check in primitive intrinsic It is having the packfulltransform info, But if I convert it to polygons and pack it again then the packfulltransform info gets ident matrix and no animating values but still the mesh is animating. My question is where does houdini stores the transform info after the animated mesh is packed.
I hope it is some what clear.
I have attached a sample file. Please someone help me to understand this.

Thanks in advance!

ofcourse the position is stored in P even there is no values in packfulltransform, but I dont know where does the rotation goes after I packed it.

Transformations are not stored anywhere, because there never was a transform. In your file, the no transform examples are from packing deforming geometry. In that case each frame is uniquely packed geometry with an identity transform. The ‘animation’ is immaterial to the packing, as it was baked by transforming unpacked geometry. A packed transform only exists if it is transformed after packing. To transform unpacked geometry without ‘baking’ it in as deforming geometry, object transforms must be used. The object merge node can optionally pack when merging an object, storing the transform as an intrinsic.

For most efficient use of a packed workflow, animated transformations are applied after packing static geometry.



Jonathan Mack

Hi Jonathan , Thanks for your reply that helped me a lot! . .
So lets say I have animated alembic mesh which im unpacking and then fracturing it and transferring back the same animation to the fracture pieces and pack them again using assemble sop. So how could I get the transform values for the packed pieces??.. I need these values because I need these pieces to take into dops as animated static object not as deformed static object. so that my constraints will work properly . . Im not sure if im explaining my situation properly , please help me.

Attached a sample file which compares packing before and after animation and result when constraining

Thanks for replies. I figured out a way to transfer back the intrinsic transform values.
I freezed the animated packed geo and used a point deform to put back the animation. its very simple and effective. even after packing Im getting the animation values.. which works cool with constraints. ..
I attached a sample check that if needed.
Thanks Jon for you explanation! It helped me to understand the deformation of packed prims