one axis sculpting

I was wondering if there is any way to use sculpting one only one axis. what I am trying to do is create a height map for a game. So the question is, is there any way to sculpt only changing the mesh on the z axis.

Why not sculpt on a plane while in Top orthographic view ?

I know I can do that, I was just wondering if there was any way to confine it to one axis, that way I can see it better while I am working.

Oh… I just found it I should have looked harder right in the sculpting options there is an option to lock one or more axies.

Look at different Brushes. Layer Brush for example has Height setting. It only sculpts in Z axis. Good for sculpting from plane up. By choosing different Curve for the Brush you should be able to control the shape of sculpt as well.

The option slitharg mentioned in 2.91 is under N > Tool > Brush Settings > Advanced > Sculpt Plane

Setting it to Z Plane allows you to only sculpt up and down