is there a better way to smooth/flatten specific areas of a mesh than the tools or modifiers?

Question

i have a model that im working on which has very detailed boots on the issue ive run into is i need the treads in the center of the boots to be completely flat without flattening out the arch between the heel and front of the foot or without flattening the outer treads however none of the smoothing tools or modifiers seem to work for the purpose or at all in general, if i use the default settings the smoothing has no effect if i go even slightly higher the entire area is warped or imploded upon itself.

I have actually gone and removed the treads by hand and added faces where they were but even that still needs some refinement but again smooth still doesn't work and i don't know of another way to quickly and accurately flatten/smooth the area i need but the modifiers and tools have little to no effect in general and with specific areas it messes them up as stated above.

Answer 1

You might try selecting the faces you want perfectly flat and scale them to zero in the z direction (assuming you want the flat aligned with the x-y plane). You can use proportional editing mode to get surrounding faces to transition toward the flat area.

Answer 2

Two fun things that helped me flatten:

S+Z,0 using the Pivot Point of Active Element for an element that should not move. Transform Orientations can add a face to become like a temporary global Z.

Using some bit of planar mesh to cut a new flat plane though a pesky mesh with the Boolean Modifier. Separate the simplest cut to outside the build for this then add it back. This modifier does work.