export as .obj with groups if it has them.
import into what ever modeling software you want ( scaling on import and export may be required depending on software )

do your thing and then export back out as .obj and load morph to your what ever it is.

If you have an .obj that has groups. You may need to use uv mapper to save the uv's and weld the object to use in some modeling software then when your don you put it back into uvmapper and apply the saved uv's. this will give you your morphed groups to then use.

I think you can even get the DS that's free and import your object to DS that has a hexagon bridge that you can then create your morphs and then bridge back to DS and you can go on from there. Export as a Pz3 with the free poser exporter or I think as an .obj but I don't use DS to know all the export options, just what I have read.