left multiply or right multiply?

[Lxiangyue]

Thanks for your great work!

May I ask why you sometimes apply left multiply on Rmat, and sometimes right multiply? Why not use the same formation? What's the difference? I'm really confused about that.

[gengshan-y]

Hi, thanks for pointing it out. There should only be left multiply in the ideal case (P'=RP+T assuming P is 3xN). But sometimes P is Nx3, in this case, I right multiply R transpose (P'=PR^T+T), which is equivalent to left multiplying R. Hopefully there is no exceptions, if there is please let me know.

[Lxiangyue]

Thanks for your clear reply! It seems that they are equal. And the attention point is using R transpose instead of R when utilizing right multiply.