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Import a 3D model of your room

Instead of typing the dimensions by hand, you can import an existing 3D model of the room: HTM reads the dimensions, the shape (including an L-shaped or open room), the attic slopes and the beams. No model? Scan the room with your phone. Here's how to get a usable file and what HTM does with it.

Where it lives in HTM

On the Room → Room tab, an “Import a 3D model” card opens the import window (drag-and-drop or file picker). 3D import is a Pro feature; typing the dimensions manually, just above, stays free and gives exactly the same result, with a bit more work.

HTM's 3D import window after reading a room.dae file: 89 meshes, classified surfaces (floor, ceiling, 10 walls), detected dimensions and 17 detected furniture objects with their type
After reading a complex model (here room.dae, 89 meshes): HTM shows the dimensions, classifies the surfaces (floor, ceiling, walls) and lists the detected furniture, ready to confirm at a glance.

Supported formats

  • glTF (.gltf, .glb) : the web standard, exported by Blender, SketchUp and most scanning apps.
  • OBJ (.obj) : universal format, present in every tool.
  • Collada (.dae) : SketchUp, older BIM.
  • Rhino (.3dm) : loaded on the fly (the first time, a ~12 MB module downloads).

For an AutoCAD .dwg file (not handled directly), first export it to .dae or .gltf from your tool.

How to export from your tool

The usual sticking point isn't HTM, it's getting a file out of your software. The most common paths:

  • SketchUp (desktop): File → Export → 3D Model… then pick COLLADA (.dae). The web/Free version has no 3D export: use the desktop version or a converter.
  • Blender: File → Export → glTF 2.0 (.glb or .gltf).
  • Rhino: Save As… to .3dm, or Export Selected to .obj.
  • Archicad / Revit / other BIM: export to COLLADA (.dae) or glTF.

Keep units in metres. If your tool exports in centimetres or millimetres, the extracted dimensions will be off: convert in the source tool, or adjust by hand after import.

No model? Scan the room with your phone

The import window offers a “Scan with your phone” button that points you to proven scanning apps (photogrammetry or LiDAR). You scan your room in a few minutes, export to .gltf or .obj, then drop the file into HTM.

  • No LiDAR (ordinary smartphone): prefer cloud photogrammetry (the phone takes photos, the server builds the mesh) : more forgiving on hardware.
  • With LiDAR (iPhone/iPad Pro): real-time scanning is fast and precise.

On export, be sure to pick a mesh (.gltf/.obj), not a “gaussian splat” / point cloud (not usable here).

What HTM reads from the model

  • Dimensions (width × length × height).
  • Room shape: rectangular, L-shaped (open room), trapezoidal or irregular, and the concavity of an L is preserved.
  • Attic: symmetric (dual-pitch) or mono-pitch slopes, with eave and ridge heights.
  • Beams and floor / walls / ceiling, from the geometry.

A 3D preview shows the model with coloured surfaces. If detection gets something wrong (a piece of furniture read as a wall, say), click the surface and correct its type (floor / ceiling / wall / exclude).

HTM 3D view of an imported furnished room: detected furniture on the floor, speakers, screen and seats
The same room once imported, in HTM's 3D view: the detected furniture sits on the floor, ready for speaker placement and acoustic analysis.

Known limitations

  • Units assumed in metres (see above).
  • Furniture: a furnished model can confuse floor/ceiling detection. Prefer an “architecture only” export, or exclude the parasitic surfaces in the preview.
  • Very shallow attics (roof pitch below ~32°): the slope is mistaken for a wall/ceiling and isn't detected: set the sloped ceiling by hand.
  • Rotated L: an L turned 45° off the axes isn't recognised as an L: reorient it in the source tool.

Then: let HTM do the work

Once the model is imported, HTM places your speakers, predicts the acoustics and checks compliance, exactly as after a manual entry. Import just saves you the tape measure.

Download HTM REW guide