Inspiration A home can look perfect in a listing and still be hard to live in. Photos rarely show whether you can enter without a step, pull a wheelchair under the sink, or reach the controls you’ll use every day. We built Sandra’s Front Door to help buyers answer those questions before they visit, and to see what a practical change might look like and cost. What it does Tell Sandra where you’re looking, your budget, and what the home needs to have. She ranks listings by the available evidence and flags must-haves that still need checking.
Open a property and Sandra rolls through its Matterport scan, guiding the camera and pointing out features relevant to your search. You can pause, revisit a room, or take over. Ask for a specific change, such as keeping the existing sink and removing the cabinets underneath, and Sandra can preview it in place and add the estimated cost to your plan. How we built it We used CoStar listing data for search, the Matterport SDK for navigation and 3D placement, and Vexcel for aerial imagery. We built the app with Flask and JavaScript and animated Sandra as a Three.js character inside the scan.
For custom edits, vision models identify the fixture and the specific part to change. We use the scan geometry and original camera views to place and review the preview at individual scan points. The guided tour plays prepared scenes and saved edits without waiting for image generation. Challenges we ran into Our first sink edit put the vanity on the neighboring wall. Another preview looked right from one spot and disappeared when we stepped back. We had to track which fixture was being edited, preserve its position, and show each preview only from a viewpoint where it lined up with the scan.
We also separated fast listing search from slower AI refinement so buyers could see matches while Sandra worked. Accomplishments that we're proud of Sandra is part of the tour itself. She moves through the rooms, leads the camera, and lets the buyer take over whenever they want. In our demo home, she can show a prepared grab-bar preview mounted on a measured wall in the actual scan. We also tested pausing, rewinding, and reopening saved edits without rebuilding them. What we learned “Accessible” is too broad to use as a single filter. A buyer who needs a step-free entrance, a buyer who needs lever handles, and a buyer who needs visual alerts are asking different questions. We also learned that a plain “check this in person” is more useful than a confident guess about a must-have. What's next for Sandra's Front Door We want to turn the walkthrough into an interactive episode. Pick a chapter, follow Sandra through the home, or switch to her eye level and see the room from her perspective. We also want to improve how edits hold up as the camera moves and help buyers turn their saved ideas into a scope they can discuss with a contractor.
