Is there a way to exclude an axis from the solidify effect? Lets say I have this object:

and I want to solidify it to 3d print it.

I would like to have a constant thickness on the XY plane.
I mean: I want that every 3d printed level has the same thickness.
If I use a Solidify modifier wiht a certain thickness (let's say 2.5mm) It works with the normal of every face, so it works also on z axis and the thickness is not always 2.5mm if measured on XY plane:


If I go to edit mode and extrude the faces I can't find a way to get what I want.

Is there a way to do it?
I don't need it to be with Solidify. It can be done with Displacement, Animation Nodes, Python or anything else. I just need to do it in a smart and quite fast way.

Thank you all in advance!
You can do it in two steps:

Extrude, but don't move E then RMB
Then push/pull using shiftZ to avoid z displacements

&quot;Push/pull&quot; is available in the tool bar (alternate from shrink/flatten) or via menu &quot;mesh/transform/push pull&quot;.
Though, you'll have to tune the distance with the mouse as the operator panel does not allow to choose the concerned axis.