ToMayaMeshConverter : Reverts "ToMayaMeshConverter : No longer set no…

…rmals" Reverts changes to no longer set normals when reading from a Cortex object to Maya mesh since by not reading the normals, we don't take into account the difference between face and vertex normals meaning Maya may not recompute the normals as expected. Also, SCCs published from outside Maya are also likely to be read into Maya with different than expected normals.
ImageEngine · Aug 29, 2024 · e1ee2c8 · e1ee2c8
1 parent 897a4dd
commit e1ee2c8
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Showing 4 changed files with 75 additions and 13 deletions.
diff --git a/Changes b/Changes
@@ -7,6 +7,7 @@ Fixes
 - USDScene :
   - Fixed round-tripping of colons in set names.
   - Fixed `hash()` to consider animation on ModelAPI extents when hashing the bound.
+- ToMayaMeshConverter : Reverted #1386 that no longer locked normals set on the Mesh from the scc to fix issues with Maya incorrectly recomputing normals as Vertex normals when they were originally computed as Face normals
 
 10.5.9.1 (relative to 10.5.9.0)
 ========

diff --git a/src/IECoreMaya/ToMayaMeshConverter.cpp b/src/IECoreMaya/ToMayaMeshConverter.cpp
@@ -183,10 +183,6 @@ void ToMayaMeshConverter::addUVSet( MFnMesh &fnMesh, const MIntArray &polygonCou
 
 bool ToMayaMeshConverter::doConversion( IECore::ConstObjectPtr from, MObject &to, IECore::ConstCompoundObjectPtr operands ) const
 {
-	// Note: Normals are not set on the Mesh from the scc as by setting them 
-	// explicitly we are implying they should be locked which is not 
-	// supported, instead we rely on Maya computing the normals everytime
-
 	MStatus s;
 
 	IECoreScene::ConstMeshPrimitivePtr mesh = IECore::runTimeCast<const IECoreScene::MeshPrimitive>( from );
@@ -267,6 +263,79 @@ bool ToMayaMeshConverter::doConversion( IECore::ConstObjectPtr from, MObject &to
 		return false;
 	}
 
+	it = mesh->variables.find("N");
+	if ( it != mesh->variables.end() )
+	{
+		if (it->second.interpolation == IECoreScene::PrimitiveVariable::FaceVarying )
+		{
+			/// \todo Employ some M*Array converters to simplify this
+			MVectorArray vertexNormalsArray;
+			IECore::ConstV3fVectorDataPtr n = IECore::runTimeCast<const IECore::V3fVectorData>(it->second.data);
+			if (n)
+			{
+				IECoreScene::PrimitiveVariable::IndexedView<Imath::V3f> normalView = IECoreScene::PrimitiveVariable::IndexedView<Imath::V3f>( it->second );
+				vertexNormalsArray.setLength( normalView.size() );
+
+				size_t i = 0;
+				for(const auto& normal : normalView)
+				{
+					vertexNormalsArray[i++] = IECore::convert<MVector, Imath::V3f>( normal );
+				}
+			}
+			else
+			{
+				IECore::ConstV3dVectorDataPtr n = IECore::runTimeCast<const IECore::V3dVectorData>(it->second.data);
+				if (n)
+				{
+					IECoreScene::PrimitiveVariable::IndexedView<Imath::V3d> normalView = IECoreScene::PrimitiveVariable::IndexedView<Imath::V3d>( it->second );
+					vertexNormalsArray.setLength( normalView.size() );
+
+					size_t i = 0;
+					for(const auto& normal : normalView)
+					{
+						vertexNormalsArray[i++] = IECore::convert<MVector, Imath::V3d>( normal );
+					}
+				}
+				else
+				{
+					IECore::msg( IECore::Msg::Warning, "ToMayaMeshConverter::doConversion", boost::format( "PrimitiveVariable \"N\" has unsupported type \"%s\"." ) % it->second.data->typeName() );
+				}
+			}
+
+			if ( vertexNormalsArray.length() )
+			{
+				MStatus status;
+				MItMeshPolygon itPolygon( mObj, &status );
+				if( status != MS::kSuccess )
+				{
+					IECore::msg( IECore::Msg::Warning, "ToMayaMeshConverter::doConversion", "Failed to create mesh iterator" );
+				}
+
+				unsigned v = 0;
+				MIntArray vertexIds;
+				MIntArray faceIds;
+
+				for ( ; !itPolygon.isDone(); itPolygon.next() )
+				{
+					for ( v=0; v < itPolygon.polygonVertexCount(); ++v )
+					{
+						faceIds.append( itPolygon.index() );
+						vertexIds.append( itPolygon.vertexIndex( v ) );
+					}
+				}
+
+				if( !fnMesh.setFaceVertexNormals( vertexNormalsArray, faceIds, vertexIds ) )
+				{
+					IECore::msg( IECore::Msg::Warning, "ToMayaMeshConverter::doConversion", "Setting normals failed" );
+				}
+			}
+		}
+		else
+		{
+			IECore::msg( IECore::Msg::Warning, "ToMayaMeshConverter::doConversion", "PrimitiveVariable \"N\" has unsupported interpolation (expected FaceVarying)." );
+		}
+	}
+
 	/// Add UV sets
 	for ( it = mesh->variables.begin(); it != mesh->variables.end(); ++it )
 	{

diff --git a/test/IECoreMaya/ParameterisedHolder.py b/test/IECoreMaya/ParameterisedHolder.py
@@ -286,6 +286,7 @@ def testMeshParameterIOProblem( self ) :
 		op = fnOP.getOp()
 
 		mesh = IECoreScene.MeshPrimitive.createBox( imath.Box3f( imath.V3f( -2, -2, -2 ), imath.V3f( 2, 3, 4 ) ) )
+		mesh[ "N" ] = IECoreScene.PrimitiveVariable( mesh[ "N" ].interpolation, mesh[ "N" ].expandedData() )
 		op.parameters()[ "input" ].setValue( mesh )
 		fnOP.setNodeValues()
 
@@ -300,13 +301,7 @@ def testMeshParameterIOProblem( self ) :
 		op = fnOP.getOp()
 
 		mesh2 = op.parameters()["input"].getValue()
-
 		self.assertTrue( mesh2.arePrimitiveVariablesValid() )
-		# The ToMayaMeshConverter relies on Maya to calculate the normals
-		# whereas createBox uses indexed normals so we cannot include them
-		# in the comparison otherwise they will never be the same
-		del mesh[ "N" ]
-		del mesh2[ "N" ]
 		self.assertEqual( mesh2, mesh )
 
 	def testOpHolder( self ) :

diff --git a/test/IECoreMaya/ToMayaMeshConverterTest.py b/test/IECoreMaya/ToMayaMeshConverterTest.py
@@ -308,9 +308,6 @@ def testNormals( self ) :
 				self.assertAlmostEqual( origNormal[j], normal3f[j], 6 )
 				self.assertAlmostEqual( origNormal[j], normal3d[j], 6 )
 
-		# normals should always be unlocked when reading from scc
-		self.assertFalse( any( maya.cmds.polyNormalPerVertex( newSphere+".vtx[*]", query=True, allLocked=True ) ) )
-
 	def testSetMeshInterpolation( self ) :
 
 		sphere = maya.cmds.polySphere( subdivisionsX=10, subdivisionsY=5, constructionHistory=False )