Fix Alembic xform (#2784) (#2786)

(cherry picked from commit 062965b)

Co-authored-by: Michael MIGLIORE <[email protected]>

Author: mwestphal

application/testing/CMakeLists.txt

@@ -787,6 +787,7 @@ if(F3D_PLUGIN_BUILD_ALEMBIC)
   f3d_test(NAME TestAlembicNonFaceVarying DATA tetrahedron_non_facevarying_uv.abc ARGS -s --load-plugins=alembic)
   f3d_test(NAME TestAlembicAnimation DATA drop.abc ARGS --animation-time=2 --load-plugins=alembic --animation-progress)
   f3d_test(NAME TestAlembicAnimationXForm DATA xform_anim.abc ARGS -g --animation-time=1.5 --load-plugins=alembic --animation-progress)
+  f3d_test(NAME TestAlembicAnimationXFormRotation DATA joint1.abc ARGS -g --animation-time=1.5 --load-plugins=alembic --animation-progress)
   f3d_test(NAME TestAlembicCurves DATA monkey_curves.abc ARGS --load-plugins=alembic THRESHOLD 0.07) #  High threshold because of line rendering
 
   if(VTK_VERSION VERSION_GREATER_EQUAL 9.3.20240707)

plugins/alembic/configs/config.d/10_alembic.json

@@ -3,7 +3,6 @@
     "match-type": "glob",
     "match": "*.abc",
     "options": {
-      "scalar-coloring": true,
       "load-plugins": "alembic"
     }
   }

plugins/alembic/configs/thumbnail.d/10_alembic.json

@@ -3,7 +3,6 @@
     "match-type": "glob",
     "match": "*.abc",
     "options": {
-      "scalar-coloring": true,
       "load-plugins": "alembic"
     }
   }

plugins/alembic/module/vtkF3DAlembicReader.cxx

@@ -263,18 +263,23 @@ class vtkF3DAlembicReader::vtkInternals
 
       this->SetupIndicesStorage(faceVertexCounts, originalData.Indices);
 
+      // By default, Alembic is CW while VTK is CCW
+      // So we need to reverse the order of indices only if the mesh is not mirrored
+      const bool doReverseRotate = matrix.determinant() > 0;
+
       // Positions
       {
         V3fContainer pV3F;
         for (size_t pIndex = 0; pIndex < positions->size(); pIndex++)
         {
-          const Alembic::Abc::V3f tp = positions->get()[pIndex] * matrix;
+          Alembic::Abc::V3f tp;
+          matrix.multVecMatrix(positions->get()[pIndex], tp);
           pV3F.emplace_back(tp.x, tp.y, tp.z);
         }
         originalData.Attributes.insert(AttributesContainer::value_type("P", pV3F));
 
         this->UpdateIndices<Alembic::AbcGeom::Int32ArraySamplePtr>(
-          facePositionIndices, pIndicesOffset, originalData.Indices);
+          facePositionIndices, pIndicesOffset, originalData.Indices, doReverseRotate);
       }
 
       // Texture coordinate
@@ -297,12 +302,12 @@ class vtkF3DAlembicReader::vtkInternals
           {
             originalData.uvFaceVarying = true;
             this->UpdateIndices<Alembic::AbcGeom::UInt32ArraySamplePtr>(
-              uvIndices, uvIndicesOffset, originalData.Indices);
+              uvIndices, uvIndicesOffset, originalData.Indices, doReverseRotate);
           }
           else
           {
             this->UpdateIndices<Alembic::AbcGeom::Int32ArraySamplePtr>(
-              facePositionIndices, uvIndicesOffset, originalData.Indices);
+              facePositionIndices, uvIndicesOffset, originalData.Indices, doReverseRotate);
           }
         }
       }
@@ -319,8 +324,9 @@ class vtkF3DAlembicReader::vtkInternals
           Alembic::AbcGeom::UInt32ArraySamplePtr normalIndices = normalValue.getIndices();
           for (size_t index = 0; index < normalValue.getVals()->size(); ++index)
           {
-            Alembic::AbcGeom::V3f normal = (*(normalValue.getVals()))[index];
-            normal_v3f.emplace_back(normal[0], normal[1], normal[2]);
+            Alembic::AbcGeom::V3f normal;
+            matrix.multDirMatrix((*(normalValue.getVals()))[index], normal);
+            normal_v3f.emplace_back(normal);
           }
           originalData.Attributes.insert(AttributesContainer::value_type("N", normal_v3f));
 
@@ -329,12 +335,12 @@ class vtkF3DAlembicReader::vtkInternals
             originalData.nFaceVarying = true;
 
             this->UpdateIndices<Alembic::AbcGeom::UInt32ArraySamplePtr>(
-              normalIndices, nIndicesOffset, originalData.Indices);
+              normalIndices, nIndicesOffset, originalData.Indices, doReverseRotate);
           }
           else
           {
             this->UpdateIndices<Alembic::AbcGeom::Int32ArraySamplePtr>(
-              facePositionIndices, nIndicesOffset, originalData.Indices);
+              facePositionIndices, nIndicesOffset, originalData.Indices, doReverseRotate);
           }
         }
       }
@@ -433,7 +439,7 @@ class vtkF3DAlembicReader::vtkInternals
         const Alembic::AbcGeom::IXformSchema& xFormSchema = xForm.getSchema();
         Alembic::AbcGeom::XformSample xFormSamp;
         xFormSchema.get(xFormSamp, selector);
-        objMatrix = matrix * xFormSamp.getMatrix();
+        objMatrix = xFormSamp.getMatrix() * matrix;
       }
 
       objects.pop();

testing/baselines/TestAlembicAnimationXFormRotation.png

@@ -68,6 +68,7 @@
 - Wolf.fbx: OLEKSO: [CC-NC 4.0](http://creativecommons.org/licenses/by-nc/4.0/)
 - world\*: VTK Data: BSD-3-Clause
 - xform_anim.abc: Public Domain
+- joint1.abc: Public Domain
 - zombie\*.mdl: LibreQuake Project: BSD-3-Clause
 
 All other datasets are licensed under the BSD-3-Clause F3D license.

testing/baselines/TestDefaultConfigFileAlembic.png

@@ -0,0 +1,3 @@
+version https://git-lfs.github.com/spec/v1
+oid sha256:dd724979117dee9212eace48d49bd59d9e968a2af2991cc56d69fe76226d57d9
+size 40129