| --- |
| license: cc-by-sa-4.0 |
| pretty_name: LaMAR splats |
| tags: |
| - gaussian-splatting |
| - visual-localization |
| - lamar |
| - indoor |
| --- |
| |
| # LaMAR as Gaussian splats |
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|
| Gaussian-splat conversions of the NavVis scan meshes of the [LaMAR](https://lamar.ethz.ch) benchmark (Sarlin et al., *LaMAR: Benchmarking Localization and Mapping for Augmented Reality*, ECCV 2022), one top-level folder per location: `hge/` (ETH main building), `cab/` (ETH CAB building) and `lin/` (Lindenhof, an old-town area of Zurich). |
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| Original data: https://cvg-data.inf.ethz.ch/lamar/, (c) ETH Zurich Computer Vision and Geometry Group and Microsoft, licensed [CC BY-SA 4.0](https://creativecommons.org/licenses/by-sa/4.0/). |
| **Changes were made.** The dataset's vertex-colored NavVis meshes were converted to Gaussians, spatially tiled and stored as SPZ v4 (details below). These derived splats are released under the same license, CC BY-SA 4.0, with attribution to the original authors. |
| No source meshes, point clouds, images or session files are included. `sources.json` lists where the originals are (URLs, member paths, sizes, sha256). |
|
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| ## Contents |
|
|
| | Session | Source mesh | Source triangles | Gaussians | SPZ GB | |
| |---|---|---:|---:|---:| |
| | `navvis_2022-02-06_12.55.11` | `mesh_simplified` | 89,028,324 | 166,800,456 | 1.71 | |
| | `navvis_2022-02-26_16.21.10` | `mesh_simplified` | 88,930,914 | 168,329,046 | 1.73 | |
| | `navvis_2021-02-18_10.02.08` | `mesh` | 337,935,451 | 546,820,597 | 5.38 | |
| | `navvis_2021-02-18_11.33.08` | `mesh` | 270,605,718 | 460,777,974 | 4.50 | |
| | `navvis_2021-05-10_19.34.30` | `mesh` | 404,160,039 | 647,286,891 | 6.29 | |
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|
| ### `cab/` and `lin/` |
|
|
| | Location | Session | Source mesh | Source triangles | Gaussians | SPZ GB | |
| |---|---|---|---:|---:|---:| |
| | CAB | `navvis_2022-06-21_09.28.22` | `mesh_simplified` | 80,791,650 | 153,009,837 | 1.54 | |
| | CAB | `navvis_2022-06-25_11.14.36` | `mesh_simplified` | 137,074,217 | 260,550,686 | 2.67 | |
| | LIN | `navvis_2022-07-03_08.30.21` | `mesh_simplified` | 191,194,343 | 364,232,909 | 3.73 | |
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| Only sessions that ship a source mesh are converted (the HoloLens and iPhone sessions of these locations have none). |
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|
| Layout: `<location>/<session>/index.json` (tile list, tile-local SPZ positions plus `offset`, Gaussian counts, recipe) and `<location>/<session>/tiles/tNNN.spz`. |
| Frame: positions are in the LaMAR global frame of the location. Each session mesh was transformed by the `pose_graph_optimized, __absolute__` pose of its `proc/alignment_global.txt` (stored as `to_global`, qw qx qy qz tx ty tz, in every `index.json`). Add the tile `offset` to the SPZ positions. |
|
|
| ## How the splats were made |
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|
| CPU-only, deterministic, no rendering or learned estimation. Recipe `analytical_source_error_v1_edge2t1.5_aniso2` of the Splataverse mesh-to-splat converter: one Gaussian per source triangle, refined on elongated triangles (edge lattice 2, threshold 1.5), Gaussians shaped to their cell (anisotropy cap 2), color from barycentrically interpolated vertex colors, opacity 0.99. Tiles are an adaptive XY partition of at most 3M source triangles. The recipe and its options are recorded in each tile receipt and `index.json`. |
| `hge/` 2022 sessions and all `cab/` and `lin/` sessions use the dataset's `mesh_simplified.ply`; the two 2021-02 and the 2021-05 `hge/` sessions use the full `mesh.ply`. We did not decimate any mesh. |
|
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| ## Known limitations |
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|
| - Appearance is per-vertex color from the dataset's meshes (no textures or materials), so surfaces are softer than the original imagery and carry no view-dependent effects. |
| - Glass is reconstructed with spurious geometry in the source meshes; windows show odd shapes and bright blobs. This comes from the source scan, not from the conversion. |
| - Sessions overlap in space and time; they are not merged or deduplicated. |
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|
