Before applyng the cloration you need to be sure that the mesh is clean, by ensuring thst all the mech verticies are weled together. This ensures that verticies are joined and no two or more closes verticies are overlapping. You can weld the edges using the following two methods.

A mesh can be recoloured by verticies allowing us to create a gradient distribution from each vertex.

To apply the coloration you first need to decontruct the mesh elements as a list.