This is a remix of the paint brush holder by Creativerso. I originally tried editing that file but in the end I just used it as a template and rebuild the brush holder from scratch using Windows 3d Builder.

This was designed to be glued to a wall of my mini painting station. I've increased the number of brush slots and I added an indentation at the bottom to stop the brushes from sliding around.

I've included the .3mf file as well so you can open it up in Windows 3D Builder and adjust the number of brush slots and overall size to fit your needs.