Ive join all meshes into one by using Ctrl + J, OK than save my work, on next day i saw meshes are separated again.
Oh! and merging Alt + M and any pick my model turns very smaller or disappear.
After doing Ctrl-J, before you save, are the meshes joined? If they are, then there is something going wrong in the saving process(or you’re opening the wrong file.) If you don’t get it sorted out post a link to your .blend file so we can see better what’s happening.
Alt-M merges vertices. So turning very small would be the expected result.
Could you please attach a .blend file? That would help us to help you! :yes: