Perform assembly/alignment of two objects Firstly, I am new to blender and have never used it until now, I search for something similar but couldn't be able to find. For my thesis, I am working with .STL files and I have a question about whether it is possible to make an assembly process between two objects using the mesh vertex's. What I want to do is place the selected vertices (image 1) coincident and perform the assembly as I make here (image 2). 

image 1: 

image 2:

I wrote a script in python to perform that "assembly" but im checking if there is a software capable of do that because it is more user-friendly and there is a thing that blender does that I need: when I move the object to any place in space, when I export that file, he puts new coordinates . So what I need is to guarantee that I can perform the correct alignment of the two objects in blender and that's ok!

Thank's for the attention
One easy way is to use vertex snapping and the origin point.


Make sure your sphere is oriented correctly.
Enable Vertex snapping > Median
Check Only origins and snap your origin point to the top vertex. Then uncheck.
Select your sphere and snap it to the other object's top vertex


Snap the origin point to the top vertex


Snap the sphere to the other object's top vertex