Exmerge

Merges the imported FBX file to the current scene in the following way:

Nodes of the same name and nature have only their animation curve replaced. No new nodes are created.

Add

Creates a new scene prior to the file import.

Merge

Merges the imported FBX file to the current scene in the following way: any node without its equivalent in the scene is created. Nodes with the same name but not of the same nature, for example, sphere and bone, are replaced. Nodes with the same name and nature only have their animation replaced.