Getfloorplan, a proptech company, uses Unreal Engine with path tracing to render photorealistic virtual tours. To maintain performance in web browsers, the company delivers static images rather than 3D models, which previously made it impossible to measure distances or geometry within the tours.
To solve this, the team implemented depth maps. These are rendered alongside the color panoramas and store the distance from the camera to the visible surface in each pixel. The depth maps are generated at a resolution of 2048x1024 pixels, while the panoramas are rendered at either 4096x2048 or 8192x4096 pixels.
The system calculates 3D coordinates by deprojecting the cursor's screen position into the world using the depth value. To determine surface normals and allow for accurate measurement, the engine samples a 3x3 or 5x5 grid of pixels around the cursor, calculating the average normal from the resulting triangle mesh.
The rendering pipeline uses specific command-line parameters to output color images, depth maps, and object ID maps. Depth data is stored in EXR files using half-float format, where one unit corresponds to one centimeter. The company manages edge cases, such as cursor movement near image boundaries, by dynamically adjusting the sampling area.
