User Manual#

Supported File Formats#

The following file formats are supported by GSplat Converter:

PLY Files (*.ply) — Standard 3D Gaussian Splat format; binary (little/big-endian) and ASCII. Required vertex properties: x y z, scale_0/1/2, rot_0..3, opacity, f_dc_0/1/2, f_rest_0..N.
SPZ Files (*.spz) — Niantic compressed Gaussian Splat format (v2 and v3).

Usage#

There are two entry points for importing Gaussian Splat files using the GSplat Converter in Kit.

File → Import#

To import a Gaussian Splat file into Omniverse, choose Import in the File menu. For .ply files you can select either the default Asset Importer (mesh path) or the 3D Gaussian Splat (Particle Field) importer. .spz files are always converted via the splat path.

Content Browser → Convert to USD#

To convert a file to USD, right-click it in the Content Browser and choose Convert to USD.

Note

There is no standalone GSplat Converter Tools window. All Kit-based conversion is handled through omni.kit.tool.asset_importer.

Converter Options#

Option	Default	Description
`--generateSh`	`false`	Synthesize SH DC coefficients from `red/green/blue` when `f_dc` properties are absent.
`--generateScales`	`false`	Estimate splat scales from KNN neighborhood spacing. Requires `scipy`.
`--up-axis`	`Y`	USD stage up-axis: `Y` or `Z`.
`--rotate-x/y/z`	`0.0`	Euler rotation in degrees (XYZ order) applied before writing. Useful to correct COLMAP Y-down orientation.
`--name`	input stem	Override the USD prim name.

For full option details, see the extension API reference:

omni.kit.converter.gsplat

CLI#

Headless batch conversion is available via the pip-installable usd-convert-gsplat CLI or the Kit shim.

# Basic conversion (pip install)
usd-convert-gsplat -i scene.ply -o scene.usda

# SPZ input
usd-convert-gsplat -i scene.spz -o scene.usdz

# Correct COLMAP Y-down orientation
usd-convert-gsplat -i scene.ply -o scene.usda --rotate-x 180

# Synthesize SH from RGB colors
usd-convert-gsplat -i scene.ply -o scene.usda --generateSh

# Z-up output stage
usd-convert-gsplat -i scene.ply -o scene.usda --up-axis Z

# From a Kit layout (shim delegates to usd_convert_gsplat)
python -m omni.kit.converter.gsplat.cli -i scene.ply -o scene.usdc

Programming Guide#

Python developers can use the Kit Python Script Editor or a standalone script to convert Gaussian Splat assets to USD programmatically.

from usd_convert_gsplat import read_ply, read_spz, write_gaussian_splat_usd

# Read a PLY or SPZ file
splat_data = read_ply("scene.ply")
# splat_data = read_spz("scene.spz")

# Write to USD
write_gaussian_splat_usd(
    splat_data,
    output_path="scene.usdz",
    source_file="scene.ply",          # optional, stored in the layer comment
    prim_name="MyScene",              # optional, defaults to the output file stem
    up_axis="Y",                      # "Y" or "Z"
    rotation_degrees=(0, 0, 0),       # Euler XYZ in degrees
)

Inside Kit, the same symbols are re-exported from omni.kit.converter.gsplat for convenience:

from omni.kit.converter.gsplat import read_ply, write_gaussian_splat_usd