Solidify makes plane thicker outwards I would like to solidify a model I am making of a plate, to give it thickness.

Here's the plate:



After I solidify, here's what I get (I increased the values to show the effect):



Solidify makes the outer edge grow, but what I wanted was just to make the object thicker (along the Z axis).

It's hard to know what to look for, but I didn't see any questions that looked like this.

Am I understanding Solidify wrong, or just using it wrong?

Here's the blend file:
Nope, you're not doing anything wrong, that's the way Solidify works.  You can make it solidify in the other direction by specifying a negative Thickness or by adjusting the Offset.