[FEM] fix sphere cut filter

when using a sphere as function for a filter, the pipeline must be recomputed when the sphere geometry is changed, not only the sphere

src/Mod/Fem/Gui/ViewProviderFemPostFunction.cpp

@@ -576,14 +576,36 @@ void ViewProviderFemPostSphereFunction::updateData(const App::Property* p) {
         getManipulator()->setMatrix(t);
     }
     Gui::ViewProviderDocumentObject::updateData(p);
-}
 
+    // after updating the geometry we must recompute the pipeline the sphere is in
+    if (p == &func->Center || p == &func->Radius) {
+        auto directParents = func->getInList();
+        // directParents is at the level of the functions container, so we must read the parent of this container
+        if (!directParents.empty()) {
+            for (auto obj : directParents) {
+                if (obj->getTypeId() == Base::Type::fromName("Fem::FemPostFunctionProvider")) {
+                    auto outerParents = obj->getInList();
+                    if (!outerParents.empty()) {
+                        for (auto objOuter : outerParents) {
+                            if (objOuter->getTypeId() == Base::Type::fromName("Fem::FemPostPipeline") ) {
+                                if (!isDragging())
+                                    // not recursve, otherwise VTK will show an error on initialization
+                                    objOuter->recomputeFeature(); 
+                                else
+                                    objOuter->recomputeFeature(true);
+                            }
+                        }
+                    }
+                }
+            }
+        }
+    }
+}
 
 FunctionWidget* ViewProviderFemPostSphereFunction::createControlWidget() {
     return new SphereWidget();
 }
 
-
 SphereWidget::SphereWidget() {
 
     ui = new Ui_SphereWidget();