How do i add more vertices to a static mesh?

Ive learned how to convert a bsp brush to a static mesh so that I can vertex paint onto it. but now It only has like 40 vertices. how do I add more vertices to my static mesh?

You could try using the tessellation multiplier within the material editor for the material applied to your static mesh. it’ll add a lot more vertices depending on what number value is plugged into it but there is not much control over it. It’s not something I’ve played around with much so not sure if its suited to what you need.