Hi gentib,
There are three ways:
1
One that uses the same geometry and uses the Pose Morph to blend. So each point has a twin in the other.
2
The other way is how images are morphed into each other. Object a will be deformed to match the shape of the object b closely. And b will be deformed closely to object a. Each deformation is animated, and the objects are blended/transitioned when they look nearly the same halfway. Eventually use a Smooth Deformer.
3
Of course, just scale and move them in place, as shown in the third file, while covering it with Volume Builder Mesher.
+ (extra)
It is not really a morph at all, more a quick set up is to use a Spherify deformer and use this as a trick to meet the shapes halfway when they closed to be a sphere.
Similar to that could be a Shrink Wrap.
But without any real information, that turns into guessing. Not my way.
So, general question, with three general answers.
Each set up has perhaps some options, as the camera moves and produces motion blur to hide things. Not to forget that most forget the option of cuts!
I have excluded here the options of progressive change like PBlurb or PolyFX could do.
Examples
https://www.amazon.com/clouddrive/share/tLYgWtgiRuB2YMEDfV7wPgkW2NEuX5HncQpGmJ58Xhp
All the best
