Select join mesh issue

I joined some meshes together, for example: object A object B and object C join together. How do I select the object A faces in edit mode?

Do you mean select parts that we’re previously object b but now are a part of the new object. You can’t (as far as I have tried). Joining objects make them one large object hence meshes becomes one mesh.
If your objects are still not attached to each others you can use lazzo mode by holding Ctrl and draw around the mesh while holding right mouse button.
From there you could separate them. To separate right click after selecting wanted mesh and choosing: separate>separate by selection.

You have to plan ahead. You will learn to use unique materials on each object in a situation like this so that you can select just those materials after a join.

thank you :smiley:

Put your mouse cursor over a face, vertex or edge of the desired part and press L (select linked). Even if they are stitched together, you can switch the modes.

:+1: Thank you so much!