i want to rotate the prim, to make the prim's normal direct to Y axis . i think it's posiable to do it by “lookat” “orient” “rotate” or something in vopsop . but i don't clearly understand about matrix, so i failled . please anyone tell me how to do it ! and how to extract the rotated information back . here is my hip file ,thank you!

Hi,

Have you tried using the “primitive” SOP?

Connect a reference primitive(s) to the 2nd input, and under “Transform/Rotate to Template” chose “Match Normals” option.

Hope it helps.

Cheers,
Greg

thank you, i have done it by three axises input to matrix and invert the matrix