Cut the opening
Arm editing, choose a window or a door, and click the wall where it goes.
Builder feature · free · in your browser
Cut Windows & Doors Online —Real Boolean Openings
An opening in Builder is cut out of the geometry — a real CSG boolean, not a texture pasted on a wall. Windows, exterior doors with steel pull handles, interior doors, sectional garage doors with panel relief and plain passages all cut clean. Openings come in rectangle, circle and triangle — triangles are there for modern-barn gables. And every daylit opening carries a RectAreaLight into the room, so interiors light correctly instead of glowing uniformly.
How it works — in the app
Pick the shape
Rectangle, circle — or triangle for the gable ends.
See it cut
The boolean goes through the wall — frame, sill and door furniture land with it.
Step inside
The room lights through the new opening — daylight is computed, not faked.
What you get
Cut windows & doors is one of fifteen feature pages covering what ships in Builder today — every claim here maps to a shipped, verified feature. The list below is the concrete surface:
- Real CSG boolean openings — the wall is cut, not faked
- Three opening shapes: rectangle, circle and triangle for modern-barn gables
- Exterior doors with steel pull handles; interior doors; passages between rooms
- Sectional garage doors with real panel relief
- Every daylit opening carries a RectAreaLight into the room — interiors light correctly
- One undoable step per change — Ctrl+Z takes the opening back out
FAQ
Why would I want a triangular opening?
Modern barn-style gables. The triangle cuts the same CSG boolean as a rectangle, so it is a real hole in the geometry — light passes through it, sections read it, and the wall adapts.
What door types are included?
Exterior doors with steel pull handles, interior doors, sectional garage doors with panel relief, and plain passages between rooms — each one cuts a proper opening, not a decal.
Will the room actually get brighter?
Yes. Every daylit opening carries a RectAreaLight into the room, and interior faces use a dimmed indoor ambient — so rooms light the way they would in reality instead of glowing uniformly.
More Builder features
Keep reading the tour, or jump back to the Explore hub for all fifteen.
Draw wallsDraw house walls online for free.Open the feature →
Study the real sunPick a place, a date and an hour — Builder computes real solar positions with the Meeus series (about 0.01°)…Open the feature →
Fit a roofPick one of four roof types and Builder auto-fits it to your exact perimeter — gable, hip, flat or shed —…Open the feature →
Open the designer and cut the first window — the light through it is real.
No install, no plugin — a house builds itself the moment the page opens.