I attached Array and Curve modifier to an object, there's no problem, but the Curve deforms the object as usual. So, my question is: What should i do to make Curve modifier not deform the objects?
The links in the comments are the answer but since I have made a picture, why not post it anyway:
Instead of deforming the object directly, deform a stack of tris. Then parent your target object (the cylinder in this example) to the deformed object and enable duplifaces for the tris in Properties >> Object >> Duplication.
Just make sure the object you want to duplicate has its scale applied or there will be deformations.