which tools in zbrush can i use that will not subdivide my mesh?

lol, it sucks when you try to do something like flatten your mesh and you find out you just divided it a few times.

The only way I know of to subdivide the mesh is by hitting Divide in the Geometry tab.

So, any of the sliders in the Deformation tab are fine to use, as well as any of the 3d sculpting brushes other than the MeshInsert ones.

Btw, even if you do accidentally subdivide the mesh, there is an SDiv slider in the Geometry tab that will allow you to go back to your original mesh size.

For simply flattening your object, look at the Size slider in the Deformation tab and choose which axis you want to flatten

what if its not as simple as choosing a side to flatten? I guess i used the wrong wording, i meant without adding any vertices. I know smoothing does the same.

You can choose one, two, or 3 sides to scale at at time...

Although, I guess I'm a bit lost on what you are trying to make *but*, the items in the Deformation tab and the 3d sculpting brushes other than the MeshInsert ones won't add any vertices to your mesh.

ok, thank you.
Sorry i meant flattening like a small partion not a whole side.

Ah, ok...what you could do is maybe mask off portions of your mesh you don't want to flatten (hold down the alt/command key then draw your mask), *then* use the slider to only flatten your unmasked portion of the object.

Or you could use one of the new planar brushes or even the mallet.

None of the brushes add more verts or subdivide a tool. A tool is your object, a brush is the thing you sculpt the tool with.