Generate a circular, square, or rectangular vent grille with honeycomb, slot, or radial openings, screw-hole patterns, and an optional removable filter-retaining frame.

This is a practical parametric grille generator for small vents, cabinet cutouts, fan openings, electronics enclosures, workshop panels, and generic indoor duct covers.

Choose the duct shape, opening size, flange width, grille pattern, screw-hole layout, and optional filter-retaining frame. The default print includes a rectangular honeycomb grille plate plus a separate screw-aligned frame that can help retain a thin filter sheet, mesh, insect screen, or dust screen behind the grille.

The OpenSCAD console prints an approximate open-area percentage and open area for the active settings. Treat this as a design guide for comparing settings, not a certified airflow rating.

Features:

- Circular, square, and rectangular duct/opening options.

- Honeycomb, slot, and radial grille styles.

- No-hole, corner/four-hole, side-center, round four-hole, and round six-hole screw patterns.

- Optional raised filter pocket rim and removable screw-aligned retaining frame.

- Support-free flat printing.

- Bounded parameters for fast MakerWorld generation.

Use PLA for indoor decorative or light utility covers. Use PETG if the grille may see warmth, sunlight, damp air, or tougher workshop handling. Do not use this as a certified HVAC, fire, appliance, high-temperature, pressure, or child-safety fan guard component.

Customization Notes

- `duct_shape` selects `circular`, `square`, or `rectangular`.

- Use `duct_diameter` for circular openings, `square_size` for square openings, and `duct_width` / `duct_height` for rectangular openings.

- `grille_style` selects `honeycomb`, `slots`, or `radial`.

- `screw_pattern` selects the mounting-hole layout.

- `filter_frame_enabled` includes a separate retaining frame in the print layout.

- `display_mode` can export the whole print kit, the grille only, or the frame only.

- `layout_direction` can switch the print-kit layout between vertical and horizontal spacing.

- For large duct sizes, export `grille_only` and `frame_only` separately or split/rearrange the STL in your slicer to fit your bed.

- Watch the echoed open-area estimate when changing grille size, bar width, or style.