1 files changed, 8 insertions, 0 deletions
diff --git a/source/blender/io/alembic/intern/abc_customdata.h b/source/blender/io/alembic/intern/abc_customdata.h
index 5eae6307474..97a9235753f 100644
--- a/source/blender/io/alembic/intern/abc_customdata.h
+++ b/source/blender/io/alembic/intern/abc_customdata.h
@@ -132,6 +132,14 @@ typedef enum {
   ABC_UV_SCOPE_VERTEX,
 } AbcUvScope;
 
+/**
+ * UVs can be defined per-loop (one value per vertex per face), or per-vertex (one value per
+ * vertex). The first case is the most common, as this is the standard way of storing this data
+ * given that some vertices might be on UV seams and have multiple possible UV coordinates; the
+ * second case can happen when the mesh is split according to the UV islands, in which case storing
+ * a single UV value per vertex allows to de-duplicate data and thus to reduce the file size since
+ * vertices are guaranteed to only have a single UV coordinate.
+ */
 AbcUvScope get_uv_scope(const Alembic::AbcGeom::GeometryScope scope,
                         const CDStreamConfig &config,
                         const Alembic::AbcGeom::UInt32ArraySamplePtr &indices);