From 4fae2b83f8be2186d6f248b4d988fa3f7da2b8b3 Mon Sep 17 00:00:00 2001
From: Kacper Donat <kadet1090@gmail.com>
Date: Tue, 6 Jan 2026 13:29:56 +0100
Subject: [PATCH] PartDesign: Apply pattern transform in Feature not VP

This is followup for https://github.com/FreeCAD/FreeCAD/pull/26563 which
fixed previews for a given file but broke it for others.

This approach should be more robust as it is applied in the Feature
itself and not on view provider level which should give us more precise
control and per feature transform ability.
---
 src/Mod/PartDesign/App/FeatureTransformed.cpp | 28 ++++++++++++++++---
 .../Gui/ViewProviderTransformed.cpp           | 15 +---------
 2 files changed, 25 insertions(+), 18 deletions(-)

diff --git a/src/Mod/PartDesign/App/FeatureTransformed.cpp b/src/Mod/PartDesign/App/FeatureTransformed.cpp
index c5fa9e914a..d218113257 100644
--- a/src/Mod/PartDesign/App/FeatureTransformed.cpp
+++ b/src/Mod/PartDesign/App/FeatureTransformed.cpp
@@ -235,19 +235,34 @@ App::DocumentObjectExecReturn* Transformed::recomputePreview()
 {
     const auto mode = static_cast<Mode>(TransformMode.getValue());
 
-    const auto makeCompoundOfToolShapes = [this]() {
+    const Part::Feature* supportFeature = getBaseObject();
+    const Part::TopoShape supportShape = supportFeature->Shape.getShape();
+
+    if (supportShape.isNull()) {
+        return App::DocumentObject::StdReturn;
+    }
+
+    gp_Trsf supportTransform = supportShape.getShape().Location().Transformation();
+
+    const auto makeCompoundOfToolShapes = [this, &supportTransform]() {
         BRep_Builder builder;
         TopoDS_Compound compound;
 
         builder.MakeCompound(compound);
         for (const auto& original : getOriginals()) {
             if (auto* feature = freecad_cast<FeatureAddSub*>(original)) {
-                const auto& shape = feature->AddSubShape.getShape();
+                auto shape = feature->AddSubShape.getShape();
+
+                gp_Trsf trsf = feature->getLocation().Transformation().Multiplied(
+                    supportTransform.Inverted()
+                );
 
                 if (shape.isNull()) {
                     continue;
                 }
 
+                shape = shape.makeElementTransform(trsf);
+
                 builder.Add(compound, shape.getShape());
             }
         }
@@ -260,9 +275,14 @@ App::DocumentObjectExecReturn* Transformed::recomputePreview()
             PreviewShape.setValue(makeCompoundOfToolShapes());
             return StdReturn;
 
-        case Mode::WholeShape:
-            PreviewShape.setValue(getBaseShape());
+        case Mode::WholeShape: {
+            auto shape = getBaseTopoShape();
+            shape = shape.makeElementTransform(supportTransform.Inverted());
+
+            PreviewShape.setValue(shape.getShape());
+
             return StdReturn;
+        }
 
         default:
             return FeatureRefine::recomputePreview();
diff --git a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
index 50c6f6ca15..d5e203d228 100644
--- a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
+++ b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
@@ -104,19 +104,6 @@ void ViewProviderTransformed::updatePreview()
 
     try {
         if (auto feature = getObject<PartDesign::Transformed>()) {
-            const Part::Feature* supportFeature = feature->getBaseObject();
-            const Part::TopoShape& supportShape = supportFeature->Shape.getShape();
-
-            if (supportShape.isNull()) {
-                return;
-            }
-
-            Base::Matrix4D invertedSupportMatrix;
-            Part::TopoShape::convertToMatrix(
-                supportShape.getShape().Location().Transformation().Inverted(),
-                invertedSupportMatrix
-            );
-
             auto originals = feature->getOriginals();
             auto transforms = feature->getTransformations(originals);
 
@@ -133,7 +120,7 @@ void ViewProviderTransformed::updatePreview()
                 auto sep = new SoSeparator;
 
                 auto transformNode = new SoTransform;
-                transformNode->setMatrix(convert(transformMatrix * invertedSupportMatrix));
+                transformNode->setMatrix(convert(transformMatrix));
 
                 sep->addChild(transformNode);
                 sep->addChild(pcPreviewShape);