From 200d9af299797763135939b42045063a68ed9e7e Mon Sep 17 00:00:00 2001
From: John Haddon <thehaddonyoof@gmail.com>
Date: Tue, 25 Aug 2026 16:57:05 +0100
Subject: [PATCH] Alembic PrimitiveReader : Support double vectors

---
 .../src/IECoreAlembic/PrimitiveReader.cpp     | 34 +++++++++++------
 .../test/IECoreAlembic/AlembicSceneTest.py    | 37 +++++++++++++++++++
 2 files changed, 59 insertions(+), 12 deletions(-)

diff --git a/contrib/IECoreAlembic/src/IECoreAlembic/PrimitiveReader.cpp b/contrib/IECoreAlembic/src/IECoreAlembic/PrimitiveReader.cpp
index 69b3bf8f7d..a2573adb97 100644
--- a/contrib/IECoreAlembic/src/IECoreAlembic/PrimitiveReader.cpp
+++ b/contrib/IECoreAlembic/src/IECoreAlembic/PrimitiveReader.cpp
@@ -67,11 +67,6 @@ void PrimitiveReader::readArbGeomParams( const Alembic::Abc::ICompoundProperty &
 			IDoubleGeomParam p( params, header.getName() );
 			readGeomParam( p, sampleSelector, primitive );
 		}
-		else if( IV3dGeomParam::matches( header ) )
-		{
-			IV3dGeomParam p( params, header.getName() );
-			readGeomParam( p, sampleSelector, primitive );
-		}
 		else if( IUcharGeomParam::matches( header ) )
 		{
 			IUcharGeomParam p( params, header.getName() );
@@ -107,11 +102,6 @@ void PrimitiveReader::readArbGeomParams( const Alembic::Abc::ICompoundProperty &
 			IV2fGeomParam p( params, header.getName() );
 			readGeomParam( p, sampleSelector, primitive );
 		}
-		else if( IV3fGeomParam::matches( header ) )
-		{
-			IV3fGeomParam p( params, header.getName() );
-			readGeomParam( p, sampleSelector, primitive );
-		}
 		else if( IC3fGeomParam::matches( header ) )
 		{
 			IC3fGeomParam p( params, header.getName() );
@@ -122,14 +112,34 @@ void PrimitiveReader::readArbGeomParams( const Alembic::Abc::ICompoundProperty &
 			IC4fGeomParam p( params, header.getName() );
 			readGeomParam( p, sampleSelector, primitive );
 		}
+		else if( IP3fGeomParam::matches( header ) )
+		{
+			IP3fGeomParam p( params, header.getName() );
+			readGeomParam( p, sampleSelector, primitive );
+		}
+		else if( IV3fGeomParam::matches( header ) )
+		{
+			IV3fGeomParam p( params, header.getName() );
+			readGeomParam( p, sampleSelector, primitive );
+		}
 		else if( IN3fGeomParam::matches( header ) )
 		{
 			IN3fGeomParam p( params, header.getName() );
 			readGeomParam( p, sampleSelector, primitive );
 		}
-		else if( IP3fGeomParam::matches( header ) )
+		else if( IP3dGeomParam::matches( header ) )
 		{
-			IP3fGeomParam p( params, header.getName() );
+			IP3dGeomParam p( params, header.getName() );
+			readGeomParam( p, sampleSelector, primitive );
+		}
+		else if( IV3dGeomParam::matches( header ) )
+		{
+			IV3dGeomParam p( params, header.getName() );
+			readGeomParam( p, sampleSelector, primitive );
+		}
+		else if( IN3dGeomParam::matches( header ) )
+		{
+			IN3dGeomParam p( params, header.getName() );
 			readGeomParam( p, sampleSelector, primitive );
 		}
 		else if( IM44fGeomParam::matches( header ) )
diff --git a/contrib/IECoreAlembic/test/IECoreAlembic/AlembicSceneTest.py b/contrib/IECoreAlembic/test/IECoreAlembic/AlembicSceneTest.py
index 8f34b9f16e..3cc171db12 100644
--- a/contrib/IECoreAlembic/test/IECoreAlembic/AlembicSceneTest.py
+++ b/contrib/IECoreAlembic/test/IECoreAlembic/AlembicSceneTest.py
@@ -2039,5 +2039,42 @@ def testArbGeomParamTypes( self ) :
 		for name in points.keys() :
 			self.assertEqual( points2[name], points[name] )
 
+	def testV3dVectorDataPrimitiveVariable( self ) :
+
+		points = IECoreScene.PointsPrimitive( IECore.V3fVectorData( [ imath.V3f( i ) for i in range( 0, 2 ) ] ) )
+
+		points["point"] = IECoreScene.PrimitiveVariable(
+			IECoreScene.PrimitiveVariable.Interpolation.Vertex,
+			IECore.V3dVectorData(
+				[ imath.V3d( i, i + 1, i + 2 ) for i in range( 0, 2 ) ],
+				IECore.GeometricData.Interpretation.Point
+			)
+		)
+		points["vector"] = IECoreScene.PrimitiveVariable(
+			IECoreScene.PrimitiveVariable.Interpolation.Vertex,
+			IECore.V3dVectorData(
+				[ imath.V3d( i, i * 2, i * 3 ) for i in range( 0, 2 ) ],
+				IECore.GeometricData.Interpretation.Vector
+			)
+		)
+		points["normal"] = IECoreScene.PrimitiveVariable(
+			IECoreScene.PrimitiveVariable.Interpolation.Vertex,
+			IECore.V3dVectorData(
+				[ imath.V3d( i, i - 1, i - 2 ) for i in range( 0, 2 ) ],
+				IECore.GeometricData.Interpretation.Normal
+			)
+		)
+
+		fileName = os.path.join( self.temporaryDirectory(), "doubleVector.abc" )
+		root = IECoreScene.SceneInterface.create( fileName, IECore.IndexedIO.OpenMode.Write )
+		root.createChild( "object" ).writeObject( points, 0 )
+		del root
+
+		root = IECoreScene.SceneInterface.create( fileName, IECore.IndexedIO.OpenMode.Read )
+		points2 = root.child( "object" ).readObject( 0 )
+		self.assertEqual( points2["point"], points["point"] )
+		self.assertEqual( points2["vector"], points["vector"] )
+		self.assertEqual( points2["normal"], points["normal"] )
+
 if __name__ == "__main__":
     unittest.main()