How to repaint certain faces/vertices using vertex paint? I have been analyzing the whole day, should I use vertex paint or a texture atlas to paint all my models in blender for my diploma thesis I am currently working on (procedural generation of a city made in low poly (painting faces with solid colors)), when I finally decided to go with vertex paint after all, because it might be a better option due to slight optimization reasons (no textures needed).

When finally I start painting my models, when I realize I can't find any way to simply repaint already colored faces with slightly different hue of color. Nothing pops up on google. Please, if anybody knows how (if) this is achievable, please help me out.



This is an example what I will be painting. I have already painted a lot of my objects using multiple materials (a while ago, when i did not know about draw calls so much), so I have all the materials assigned with colors I want on my objects, maybe UV texturing is the way to go, because I can somehow select the faces with already assigned material and just drop them on appropriate color in texture?

[EDIT]:

I have gone to UV mapping due to the reason it seems way faster to alter color of already colored faces rather than using vertex paint. See the work in progress below.
I personally hate the built-in painting tool in Blender. It works fine for planes, but on more complex 3D meshes it fails badly. 

If you insist on painting the faces a solid color, you can change to face select in painting mode, so you can select the faces you want to apply color to. This is a quick way of doing what you want, but you have to go over every face in every angle to get a clean solid color on your mesh. Leave a comment below if you want screenshots of how to do this.

Alternatively, you can also use the fill tool on the selected faces to make quick work of the repainting process.

A plugin that I myself have not tested yet, is this one. It allows you to select all faces with the same color automatically for easier repainting.

I personally use UV textures for pretty much everything that's textured. If I use the built-in painting tool, it's simply to mark which faces are what in a solid color, so I can easily recognize it later in external editing.

Hope this helps.