This plugins adds the option to draw custom shapes on the landscape and convert them to a custom Spline and fill it with a Dynamic Mesh Component.
Clone the repository into your /plugins folder.
Use the "Add Location" and "Remove Location" blueprint nodes to add and remove areas. For example in Event Tick or with a keyboard input action.
When painting large areas you may find the performance drop while painting. You can use the "Generate Mesh" and "Update Spline" nodes to reduce the performance impact. e.g. call them only once every x seconds.
Simply configure a material by using the Dynamic Mesh Component -> Configure Material Set node.