Auto UV Unwrap#

Key: generateAtlasUVs

This operation generates texture (UV) coordinates for mesh prims with lower distortion than projection-based methods, writing them as the face-varying st primvar. It segments each mesh into patches, flattens them to 2D, and packs the patches into a single atlas.

Tuning#

distortionThreshold (default 3) is the primary dial: it bounds how much stretch a patch may have before it is cut. Lower values produce more, smaller patches (more seams, less distortion); higher values produce fewer patches (fewer seams, more distortion). The value is clamped to a minimum of 1.05.

enableAtlasPacking (default true) packs all patches into one atlas; disable it to leave patches unpacked. overwriteExisting (default true) regenerates UVs even where an st primvar already exists; set it false to preserve authored UVs.

World-space scaling#

When useWorldSpaceScales is true (default), texel density is derived from world-space size using scaleFactor and scaleUnits so UV scale is consistent across meshes of different sizes. These scale inputs are in stage units and should track metersPerUnit.

Notes#

UVs are written as face-varying st. Meshes with time-varying topology, instance proxies, or unauthored topology are skipped. An empty paths processes all meshes.

Starting configurations#

Default unwrap:

[{"operation": "generateAtlasUVs", "distortionThreshold": 3.0}]

Low-distortion (more seams):

[{"operation": "generateAtlasUVs", "distortionThreshold": 1.5}]

Arguments#

Meshes to generate UVs for#

Optional list of prim paths to consider

  • Name: paths

  • Type: [string]

  • Default Value: []

Distortion Threshold#

Lower values reduce distortion but increase number of UV islands. Should be > 1.

  • Name: distortionThreshold

  • Type: float

  • Default Value: 3

Enable Atlas Packing#

Enable atlas packing for AutoUV unwrap

  • Name: enableAtlasPacking

  • Type: bool

  • Default Value: True

Use World Space Scales#

Scales UV islands to world space dimensions of the source mesh

  • Name: useWorldSpaceScales

  • Type: bool

  • Default Value: True

Scale Factor#

Uniform scale factor to apply to UV islands to change texel density

  • Name: scaleFactor

  • Type: float

  • Default Value: 0.01

Scale Units#

Real world unit in which the scale factor is described

  • Name: scaleUnits

  • Type: float

  • Default Value: 0

Overwrite Existing#

Overwrite existing UVs on the meshes selected for processing

  • Name: overwriteExisting

  • Type: bool

  • Default Value: True