I found the solution, maybe it will be helpful for other noobs, who starts with three.js
Here is working example:
Explainations in few words:
I used MorphTargets!
I’ve created first Shape for represent first step of my animation, and create first geom
I’ve created second Shape for represent last step of my animation, and create second geom
I’ve push following object to my first geom.morphTargets
var geometry = new THREE.ExtrudeGeometry( shape, extrudeSettings );
var geoShapeTwo = new THREE.ExtrudeGeometry( shapeTwo, extrudeSettings );
geometry.morphTargets.push({vertices: geoShapeTwo.vertices})
Next I created mesh object used first geom. It gives me possibility to morph my object by change of this value: box.morphTargetInfluences[0]. Value has range from 0 to 1. If it is closer to 0 - animation will be closer to first shape. If it is closer to 1 - animation will be closer to second Shape.
For better understand just check animatedShape() method in my example.
I’m not sure, that this is fine solution. I need to check perfomance. Anyway, I hope, that this primitive animation will help someone with hard first steps in three.js.
If you have any suggestions about performance, will be grateful