I was trying to rotate children of an object, in it's place, but the local and world coordinates where (0,0,0) even if they were not in that position in the original.
It looks like, .obj format is changing children original position eg (4, 0, -2) puts them in that position and change the coordinates to (0,0,0) so there is no possible way to get the original ones.
I checkd that .3ds format keeps the object position correctly as also the collada format. It's weird what happens with .obj after export.
Anyone had this issue before?
Thanks for help!