Does anyone know how to do that? 
I had some problems with my pyramid, cause its base was not on the ground plane. Tried to find a solution, but just ended up moving the whole thing manually with the maximum zoom…Which doesn’t seem to be a nice way.
P.S. Does anyone know a solution for the situation when the grid is very big to snap the bottom edge to it? I managed to do it, but also in a bit of a clumsy way…
Thanks in advance everyone!
Assuming that you started from the basic cube and didn’t change its height (apart the the extrusion of course):
*Select the bottom plane of the base
*Hit “g” to translate and then “z” to constrain the translation to along the z axis
*Then hit “1” to raise the base up to the xy plane
The height of the base cube is 2, so moving the bottom of the plane up by one brings it to the xy plane.
If you changed the the default cube’s height, here is another way:
*type “shift”+“c” to recenter the cursor on the origin
*in edit mode, select the bottom plane of the pyramid
*type “shift”+“s” and then select “selection to cursor (offset)”
I hope I understood your question right and I hope this helps!
I like the bottom method because you don’t have to know the dimensions for it to work correctly. Great answer.
Thanks a lot!
That solves it, for the case when one is thinking in advance and does it with a base-shape… So from now on I will be doing it in the beginning of the project
But is there a way to align the surface of an object to grid without changing the thickness of the object, like moving the whole thing in such a way, that its bottom surface is on the grid?
Right now, with method 2, the bottom surface moves to grid, which makes the bottom step thinner. Is there a way to make the whole geometry move accordingly?
I hope I am explaining it clear… 