Expandable Window Cat or Dog Door System (updated)

Overview

Give your cat or dog the freedom they deserve without permanently modifying your home. This modular, expandable window cat door is designed to fit a wide range of window sizes by using a simple interlocking filler system. Just print the main door section, add as many extension panels as needed, and create a custom-fit solution for nearly any window opening.

Whether you're providing access to a screened patio, catio, enclosed pool area, or simply allowing your feline friends to move between spaces, this design keeps installation easy and completely reversible.

V2 - Update included vertical option and snapfit door for better movement

✨ Features

- 🐱 Comfortable Flap - Smooth swinging door allows easy entry and exit. - Sized for everyday use by most adult cats. - 🧩 Fully Modular Design - Print only what you need. - Interlocking filler sections expand the system to match your specific window width. - 🪟 Custom Window Fit - Works with a variety of horizontal window openings. - Great for renters or homeowners who don't want permanent alterations. - 🔒 Tool-Free Installation - Slides into place using the window itself to secure the assembly. - No screws, drilling, or adhesives required. - 🖨️ Easy to Reprint - Damaged section? Simply reprint that piece instead of replacing the entire unit. - ☀️ Perfect for Catios & Pool Enclosures - Provides convenient access while maintaining separation between indoor and outdoor spaces. Recommended Print Settings

- Layer Height: 0.20 mm - Wall Loops: 4 - Top/Bottom Layers: 5 - Infill: 15–20% Gyroid - Supports: Not Required (depending on flap orientation) - Brim: Recommended for larger extension pieces - Nozzle: 0.4 mm - Material: PETG recommended for durability and heat resistance Material Recommendations

PLA

✅ Easy to print ⚠️ Best for indoor-only installations

PETG (Recommended)

✅ Heat resistant ✅ Durable ✅ Better for Florida windows and sun exposure

ASA

✅ UV resistant ✅ Excellent for outdoor applications ⚠️ Requires an enclosed printer