Create custom Splat brush

To define your own brush, first you have to create a …/Resources/SplatBrushes folder somewhere in your project, then right-click on the Project window, select Create > Polaris > Splat Brush. A new brush asset will appear, assign appropriate value for it:

Remember to assign proper collection name for better grouping in the Gallery.

Save the Project, then go back to the Splat painter, you would see the brush loaded.