Hi, For some reason when Im vertex painting by brush size is not working, when the minimun size is set to 0 the brush is still large and as soon as I change the size even just a little it goes huge.
As you can see there is little difference in the brush size yet visually there is a massive difference.
Silly question: have you tried re-starting the editor?
Also, how many vertices does that road mesh have? You need a high ( ish ) poly mesh to use vertex painting…