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Extract Rotation Problem

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I searched the vollume and youtube to find out extract transform and rotation from animated objects

I was able to produce the same result with  the CG Forge tutorial (www.youtube.com/watch?v=iSiyGr8p0p4&t=326s)

But when I applied to my animated object in sop somehow the transform is ok but the rotation failed completely

Can anyone point out what I did wrong?


Thank you




Edited by Max_Steven
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the reason your rotation gets lost is because you pack it, after the transformation has been applied, Thus rendering the primitive intrinsics to just an ident matrix.

If you look at the Crag test geometry, although he is packed he still has the packed intrinsic transform matrix information:



Your geometry does not:



If you want it to work with your tube as well, just apply the transform node after you pack the geometry and it will work properly.


Edited by Jesper Rahlff
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Thank you for the reply

Now I get it but what if I have alembic geo from maya instead of crag/tube.

It wont have orient data either right, so the only way to do is point deform?

Do you think is there any way to extract transform from geo in that case?

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Thank you for your reply

I can replicate what you said with Craig but when apply to the geo cache it's just not working

Maybe because the original cache is deformed mesh therefore it doesnt have the rotation data?

In this case what should I do? 

Sorry for my small brain


I couldnt upload the geo cache file so here is the google drive link


Edited by Max_Steven
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You can't derive a rotation matrix just from a single point without any other information.

If you want to align your sim to another object like thrusters, there are many ways like isolating a single central face and aligning the simulation using Extract Transform SOP to extract the transformation matrix. You just have to make sure there is a reference frame of the engine that's also aligned to world axes and at the origin so the simulation at the origin can be matched perfectly to the animated version. Post offsets can be applied after transform matching.

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