Fluent 4 - Hard Surface Modeling Tool Suite is an add-on for Blender from CG Thoughts, focused on hard surface modeling through a non-destructive workflow. It works with boolean operations and modifiers, functioning as a cutter add-on for shaping and cutting hard surface geometry.
The add-on is compatible as a Blender extension and supports Blender versions 3.6 through 5.0. Its listing spans a wide range of render engines, including Cycles, Eevee, Arnold, Octane, V-Ray, Luxrender, Yafaray, Freestyle, Mental Ray, and Blender's internal and game engines. Documentation is provided, and a demo video is available.
On Superhive the add-on ranks 14th, and it carries a 5-star rating from 132 ratings along with more than 16,000 sales. Fluent 4 is released under the GPL license and comes from CG Thoughts, with documentation included to help users get started.