UVMapping

4 tools. Back to the index.

clear_uv_channel

Destructive, idempotent.

Drop all UVs from one UV channel on a static mesh. Idempotent on already-empty channels. Resizes the UV-channel count if the cleared channel is the highest one (UE 5.8 doesn't auto-shrink channel count, so callers that want to "remove" a UV channel should follow up with set_num_uv_channels).

Parameter	Type	Required	Description
static_mesh_path	string	yes	Asset path to the UStaticMesh
uv_channel	number	no	Index of the UV channel to clear (0-based; default 0)

Returns: { static_mesh_path, uv_channel, uv_channel_count_before, uv_channel_count_after, cleared, saved }

get_uv_health_report

Read-only.

Read-only diagnostic summary for one UV channel on a static mesh: counts, lightmap status, in-unit-square ratio, overlap count, and unique UVs.

Parameter	Type	Required	Description
mesh_path	string	yes	Static mesh path (e.g. /Game/Meshes/Cube)
lod_index	number	no	LOD index to inspect (default 0)
uv_channel	number	no	UV channel index to inspect (default 0)

Returns: { mesh_path, lod_index, uv_channel, vertex_count, triangle_count, lightmap_coordinate_index, no_lightmap_configured: bool, is_lightmap_hard_failing: bool, approx_overlap_count, in_unit_square_triangle_ratio, approx_unique_islands, per_triangle_iteration_error?: string } -- approx_unique_islands counts distinct UV positions (rounded to 4 decimals), not islands; when per_triangle_iteration_error is set the per-triangle counters stay 0.

list_uv_channels

Read-only.

Per-LOD inventory of UV channels on a static mesh (read-only, no MarkDirty / no save).

Parameter	Type	Required	Description
mesh_path	string	yes	Static mesh path (e.g. /Game/Meshes/Cube)
lod_index	number	no	Optional LOD index to inspect, or -1 to inventory every LOD (default -1)

Returns: { mesh_path: string, total_lods: int, lods: [{lod_index, uv_channel_count, vertex_count, triangle_count, lightmap_coordinate_index, has_lightmap, channels: [{channel, is_lightmap, vertex_count}]}] }

set_triangle_uvs

Destructive, idempotent.

Set the 3 UV corners of a single triangle in one UV channel. Use this for granular UV edits without a full repack / regeneration. The triangle becomes an isolated UV island (the engine allocates fresh UV elements per call). Triangle IDs are 0-based into the mesh's triangle list. The bIsValidTriangle out-param surfaces the engine's validity verdict (false if TriangleID is out of range, the UV channel doesn't exist, or the resulting topology would be invalid).

Parameter	Type	Required	Description
static_mesh_path	string	yes	Asset path to the UStaticMesh
uv_channel	number	no	UV channel index (default 0)
triangle_id	number	no	Triangle ID to update (0-based; default 0)
uv0	array	no	First triangle corner as a [u, v] pair. Read by the local ParseUV helper, which the extractor cannot follow, so this hint is what puts the param in the schema at all -- documenting the three on one line made all three unparseable and the tool had NO way to pass UVs.
uv1	array	no	Second corner as [u, v].
uv2	array	no	Third corner as [u, v]. Alternatively pass the six flat numbers u0/v0/u1/v1/u2/v2 instead of the three arrays.

Returns: { static_mesh_path, uv_channel, triangle_id, is_valid_triangle, modified, saved }