Change one dimension and the whole frame follows
A catio in OpenCatio3D is not a decorative box. It is a frame of real members — posts, plates, rafters, rails, door studs — generated from your dimensions, so the drawing and the materials list can never disagree.
Templates that stay editable
Start from a lean-to, a freestanding box, a window box or a tunnel. Width, depth, heights, framing size, roof type, base and openings stay editable for the life of the project.
- Lean-to — high side on a ledger at the house wall, sloping to a lower front.
- Freestanding — four walls and a roof, anchored to the ground, pavers or a deck.
- Window box — a small enclosure hung on brackets outside a window.
- Tunnel — a mesh run between a window and a catio, or along a fence.
Rules, not magic
Walls split into equal bays so post and rafter spacing stays under a maximum you can see and change. Lumber is named by nominal size (2×2, 2×3, 2×4) but drawn and cut at its actual dimensions. Stock lengths, saw kerf, mesh roll size and overlap are explicit settings — not hidden constants.
Every generated part has a stable id and the recipe that made it, so a part number on the cut list is the same part in the 3D view and in the assembly steps.
Fail closed
Combinations the generator does not support — a balcony, an elevated deck, an unusually large span — fall back to concept only: you can design and share them, but no build package is issued until the design changes or a professional reviews it.
In the beta
- Lean-to, freestanding, window box and tunnel templates
- Wood frame (2×2, 2×3, 2×4) with welded wire mesh
- Mesh, corrugated, polycarbonate and partial roofs
- Human doors, cat doors, cleaning hatches and vestibules
Planned
- Porch infill and balcony templates beyond concept mode
- Modular metal and composite panel systems
- Manufacturer catalogs
Questions
Can I draw any shape I like?
Not yet. The planner generates construction only for shapes whose framing rules it can check. That is deliberate: a materials list is only useful if the shape behind it is buildable.
Does it do structural engineering?
No. Outputs are planning and construction guidance within the supported limits, not stamped engineering drawings. Elevated, roof-mounted, large or high-wind and heavy-snow designs are flagged for professional review.
Related
Design your catio in your browser
Free to design and check. Fit a catio to your wall, window and yard, run the safety checks, and see the materials list before you buy a single board.