From e4cec83945982bdc8c028803db4efe6a095cba4d Mon Sep 17 00:00:00 2001
From: Uwe <donovaly@users.noreply.github.com>
Date: Mon, 28 Mar 2022 02:41:38 +0200
Subject: [PATCH] [FEM] fix crash in pipeline creation

fixes #6670
---
 src/Mod/Fem/App/FemVTKTools.cpp | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/src/Mod/Fem/App/FemVTKTools.cpp b/src/Mod/Fem/App/FemVTKTools.cpp
index 8e0c6d77a8..52cffa266b 100644
--- a/src/Mod/Fem/App/FemVTKTools.cpp
+++ b/src/Mod/Fem/App/FemVTKTools.cpp
@@ -933,7 +933,9 @@ void FemVTKTools::exportFreeCADResult(const App::DocumentObject* result, vtkSmar
             SMDS_NodeIteratorPtr aNodeIter = meshDS->nodesIterator();
             for (size_t i = 0; i < vec.size(); ++i) {
                 const SMDS_MeshNode* node = aNodeIter->next();
-                data->SetValue(node->GetID() - 1, vec[i] * factor);
+                // for the MassFlowRate the last vec entries can be a nullptr, thus check this
+                if (node)
+                    data->SetValue(node->GetID() - 1, vec[i] * factor);
             }
 
             grid->GetPointData()->AddArray(data);