Installation

In Blender open Edit, Preferences, Get Extensions, then use Install from Disk and pick the pen_generator zip.

Usage

1. Open the Pen tab in the 3D viewport sidebar (N). With no pen selected, click a family and a pen picture, then Add Pen to add it at the 3D cursor. You can also use Shift+A, Mesh, Pen, or Add a Set of Pens for a row of pens of one family.
2. The card at the top shows the selected pen, its size and point. Click its picture to switch to another design. Surprise makes a random pen, Vary gives the same design a new size, colors and trim, and the arrow resets it.
3. The icon tabs hold every setting: Body (length, diameter, section, silhouette, front section, pattern), Point (writing point, nib, lead, ink), Cap and Clip, Parts (end, grip, insides), Materials and Export (mesh detail, pose, finish as a plain mesh).
4. The trash button deletes a pen together with materials nothing else uses.

Every pen is one mesh with PBR materials, so it exports to game engines with glTF or FBX. Use File, External Data, Pack Resources before sending a .blend to someone else.