This was inspired by https://www.thingiverse.com/thing:4154973 I found that design was too small and didn't fit the brushes that I own well, but I loved the core concept. The new design is nice and small and fits in my travel bag for using when I'm away on the road. When painting if you need to put the brush down, having it at an angle stops the paint migrating into the ferrule and ruining the brush. Its the same when you have finished and have washed the brush. After a light dry on a paper towel, this is an ideal way of letting it dry naturally. The angle allows any remaining liquid to drain off, rather than inside the brush. I do this before putting it into a bigger paint brush rack (such as one of my other designs! https://www.thingiverse.com/thing:6299813) I have made it customisable to allow it to work for different sizes, number of brushes and brush sizes. Hopefully if the standard STL I have included isn't quite right you can use it to design one that is. A brief overview of the parameters used:

frame_xsize : The Length of the drying frame
frame_ysize : The width of the drying frame
frame_thickness : How thick each part of the frame is
brush_thick_end : The diameter of the thickest end of the paint brush
brush_thin_end : The diameter of the thinnest end of the paint brush
brush_angle : Determines the angle of the frame. 0 would be
num_brushes : How many brushes to automatically fit onto the frame
brush_offset : How far from the side the brush will appear. 0 being right on the edge of the frame
brush_embed_offset : Offset so the brush isn't embedded too far into the frame. A bit of a fudge factor!
bottom_angle_height : How high the lowest point of the frame is. The high end is calculated automatically from the the frame_xsize and angle.
show_brush_model : Show the simplified brush model based on the two end diameters. Useful to visualise how it will look.

Found 11 3D-models for “paintbrush rack” across many websites

Paint Brush Pen Pencil Tool Rack Holder Stand

Paint/make-up brush dry rack

Vase Mode - Art Tools Organizer

Paint brush stand

Paintbrush Wash and Rinse Rack

Paintbrush holder

Paintbrush & Pencil Holder

Paintbrush Rack

Customisable Paintbrush Drying Rack

Voronoi Pen Holder

Small Paint Palette/Organizer for Vallejo Bottles