Does it possible to make some morphing between 2 different volumes (say a tore and a cube) who have same numbers of polygon?
If Yes I have forgotten the process 
Yes, all you need is to have one as an OBJ. Then import it after having stored the morph target. As you say, the vertex count must be the same. Once imported you can use the Morph brush or whatever.
Edit: I forgot that the ztool must have subdivision levels, and you must be at the correct level to import. There needs to be the same number of vertices and polygons.
Cheers,
…to know that is possible
because seems don’t work in Demo version
with 2 different primitives (Helix 3D & Spiral 3D) who are Polymeshed3D 
(import obj does not permit)
Yes, that works, after a fashion. 
Problems will arise if the shapes are wildly different because of the way the points would have to move (in other words, the model would explode. ). It’s best to use meshes with the same origin.
