This is a very short Blender tip on instantiating objects. I use Blender for many years now but I never knew about this feature – Instantiating instead of creating a duplicate.
Let’s start with the default cube and create a duplicate of it by pressing Shift + D. Now press the Y key and move the object to the right:
After that select the cube in the center, switch to edit mode, select the top face in face selection mode, change the size (S key) and see what happens to the cube on the right side. Yes, nothing. Because it is a copy that has no relation to the original:
But now select the object in the center again in object mode and press Alt + D keys to instantiate. You are also duplicating the object with this action, press Y key and move it to the left. Now again, switch to edit mode, select a face and change the size:
Yes, both objects are connected and as you change one of those both are modified. The most of you guys knew this I guess, but I learned this today:-)by