From c5c937c8bdecc40883c5916bd6afdfbfa47318c5 Mon Sep 17 00:00:00 2001
From: Kacper Donat <kadet1090@gmail.com>
Date: Wed, 31 Dec 2025 17:09:43 +0100
Subject: [PATCH] PartDesign: Fix misplaced preview for patterns

Previous solution did not take into account supporting shape transform
which should now be handled correctly.
---
 .../PartDesign/Gui/ViewProviderTransformed.cpp    | 15 ++++++++++++++-
 1 file changed, 14 insertions(+), 1 deletion(-)

diff --git a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
index d5e203d228..50c6f6ca15 100644
--- a/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
+++ b/src/Mod/PartDesign/Gui/ViewProviderTransformed.cpp
@@ -104,6 +104,19 @@ 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);
 
@@ -120,7 +133,7 @@ void ViewProviderTransformed::updatePreview()
                 auto sep = new SoSeparator;
 
                 auto transformNode = new SoTransform;
-                transformNode->setMatrix(convert(transformMatrix));
+                transformNode->setMatrix(convert(transformMatrix * invertedSupportMatrix));
 
                 sep->addChild(transformNode);
                 sep->addChild(pcPreviewShape);