I resolved it by clear the mesh in the parent blueprint and just set it in the child. Don’t know why put the same mesh in both make it invisible but, well, it’s a “solution”.
By the way, animations don’t play in cooked game, if someone have an idea (?) but I think it’s an other problem.
Edit : Well it wasn’t an other problem, inheritance seems to be guilty. Animation problem can be solve the same way as the invisible problem but now the rotation of the mesh don’t follow when the character run.
! Inheritance seems not to be support in the built, all is reset. Anyone knows how to solve it ? Is it a bug or just … a feature i don’t want to use and don’t know how to disable ?