diff -r 95f8ca75d1e0 core/api.cpp
--- a/core/api.cpp	Wed Jan 11 19:42:56 2012 +0100
+++ b/core/api.cpp	Sat Jan 14 18:40:13 2012 -0700
@@ -582,6 +582,11 @@
 	Context::GetActive()->SaveFLM(string(name));
 }
 
+extern "C" void luxMergeFLM(const char* name)
+{
+	Context::GetActive()->MergeFLM(string(name));
+}
+
 extern "C" void luxOverrideResumeFLM(const char *name)
 {
 	Context::GetActive()->OverrideResumeFLM(string(name));
diff -r 95f8ca75d1e0 core/api.h
--- a/core/api.h	Wed Jan 11 19:42:56 2012 +0100
+++ b/core/api.h	Sat Jan 14 18:40:13 2012 -0700
@@ -113,9 +113,10 @@
 LUX_EXPORT void luxMotionInstance(const char *name, float startTime, float endTime, const char *toTransform);
 LUX_EXPORT void luxWorldEnd();
 
-/* Load/Save FLM file */
+/* Load/Save/Merge FLM file */
 LUX_EXPORT void luxLoadFLM(const char* name);
 LUX_EXPORT void luxSaveFLM(const char* name);
+LUX_EXPORT void luxMergeFLM(const char* name);
 /* Overrides the resume settings of the Film in the next scene to resume from the given FLM file, or use filename from scene if empty */
 LUX_EXPORT void luxOverrideResumeFLM(const char *name);
 /* Overrides the Film output filename */
diff -r 95f8ca75d1e0 core/context.cpp
--- a/core/context.cpp	Wed Jan 11 19:42:56 2012 +0100
+++ b/core/context.cpp	Sat Jan 14 18:40:13 2012 -0700
@@ -1054,6 +1054,25 @@
 	luxCurrentScene->SaveFLM(flmFileName);
 }
 
+void Context::MergeFLM(const string &flmFileName) {
+	lux::Film *film = luxCurrentScene->camera->film;
+
+	std::ifstream ifs(flmFileName.c_str(), std::ios_base::in | std::ios_base::binary);
+	if(ifs.good()) {
+		// read the data
+		LOG(LUX_INFO,LUX_NOERROR) << "Merging FLM file: " << flmFileName;
+		float newSamples = film->UpdateFilm(ifs);
+		if (newSamples <= 0) {
+			LOG(LUX_SEVERE,LUX_NOFILE) << "Error reading FLM file '" << flmFileName << "'";
+		} else {
+			LOG(LUX_INFO,LUX_NOERROR) << "Merged " << newSamples << " samples from FLM file";
+		}
+	}
+	else
+		LOG(LUX_SEVERE,LUX_NOFILE) << "Error opening FLM file '" << flmFileName << "'";
+	ifs.close();
+}
+
 // Save current film to OpenEXR image
 void Context::SaveEXR(const string &name, bool useHalfFloat, bool includeZBuffer, int compressionType, bool tonemapped) {
 	luxCurrentScene->SaveEXR(name, useHalfFloat, includeZBuffer, compressionType, tonemapped);
diff -r 95f8ca75d1e0 core/context.h
--- a/core/context.h	Wed Jan 11 19:42:56 2012 +0100
+++ b/core/context.h	Sat Jan 14 18:40:13 2012 -0700
@@ -141,6 +141,7 @@
 	// Load/save FLM file
 	void LoadFLM(const string &name);
 	void SaveFLM(const string &name);
+	void MergeFLM(const string &name);
 	void OverrideResumeFLM(const string &name);
 	void OverrideFilename(const string &filename);
 
diff -r 95f8ca75d1e0 qtgui/luxrender.ui
--- a/qtgui/luxrender.ui	Wed Jan 11 19:42:56 2012 +0100
+++ b/qtgui/luxrender.ui	Sat Jan 14 18:40:13 2012 -0700
@@ -1179,6 +1179,7 @@
     <addaction name="action_resumeFLM"/>
     <addaction name="action_loadFLM"/>
     <addaction name="action_saveFLM"/>
+    <addaction name="action_mergeFLM"/>
     <addaction name="separator"/>
     <addaction name="action_Save_Panel_Settings"/>
     <addaction name="action_Load_Panel_Settings"/>
@@ -1220,6 +1221,11 @@
     <string>Save FLM...</string>
    </property>
   </action>
+  <action name="action_mergeFLM">
+    <property name="text">
+      <string>Merge FLM...</string>
+    </property>
+  </action>
   <action name="action_exitAppSave">
    <property name="text">
     <string>Save and Exit</string>
diff -r 95f8ca75d1e0 qtgui/mainwindow.cpp
--- a/qtgui/mainwindow.cpp	Wed Jan 11 19:42:56 2012 +0100
+++ b/qtgui/mainwindow.cpp	Sat Jan 14 18:40:13 2012 -0700
@@ -73,6 +73,7 @@
 int EVT_LUX_TONEMAPPED = QEvent::registerEventType();
 int EVT_LUX_FLMLOADERROR = QEvent::registerEventType();
 int EVT_LUX_SAVEDFLM = QEvent::registerEventType();
+int EVT_LUX_MERGEDFLM = QEvent::registerEventType();
 int EVT_LUX_LOGEVENT = QEvent::registerEventType();
 int EVT_LUX_BATCHEVENT = QEvent::registerEventType();
 int EVT_LUX_NETWORKUPDATETREEEVENT = QEvent::registerEventType();
@@ -166,6 +167,7 @@
 	connect(ui->action_resumeFLM, SIGNAL(triggered()), this, SLOT(resumeFLM()));
 	connect(ui->action_loadFLM, SIGNAL(triggered()), this, SLOT(loadFLM()));
 	connect(ui->action_saveFLM, SIGNAL(triggered()), this, SLOT(saveFLM()));
+	connect(ui->action_mergeFLM, SIGNAL(triggered()), this, SLOT(mergeFLM()));
 	connect(ui->action_exitAppSave, SIGNAL(triggered()), this, SLOT(exitAppSave()));
 	connect(ui->action_exitApp, SIGNAL(triggered()), this, SLOT(exitApp()));
 	connect(ui->action_Save_Panel_Settings, SIGNAL(triggered()), this, SLOT(SavePanelSettings()));
@@ -351,6 +353,9 @@
 	m_saveTimer = new QTimer();
 	connect(m_saveTimer, SIGNAL(timeout()), SLOT(saveTimeout()));
 
+	m_mergeTimer = new QTimer();
+	connect(m_mergeTimer, SIGNAL(timeout()), SLOT(mergeTimeout()));
+
 	m_netTimer = new QTimer();
 	connect(m_netTimer, SIGNAL(timeout()), SLOT(netTimeout()));
 
@@ -372,6 +377,7 @@
 	m_updateThread = NULL;
 	m_flmloadThread = NULL;
 	m_flmsaveThread = NULL;
+	m_flmmergeThread = NULL;
 
 	m_batchProcessThread = NULL;
 	batchProgress = NULL;
@@ -427,6 +433,7 @@
 	delete m_updateThread;
 	delete m_flmloadThread;
 	delete m_flmsaveThread;
+	delete m_flmmergeThread;
 	delete m_renderTimer;
 	delete m_batchProcessThread;
 	delete renderView;
@@ -751,6 +758,30 @@
 	m_flmsaveThread = new boost::thread(boost::bind(&MainWindow::flmSaveThread, this, flmFileName));
 }
 
+void MainWindow::mergeFLM(QString flmFileName)
+{
+	if( !luxStatistics("sceneIsReady") && !luxStatistics("filmIsReady") )
+		return;
+
+	if(m_guiRenderState == WAITING )
+		return;
+
+	if (flmFileName.isNull() || flmFileName.isEmpty())
+			flmFileName = QFileDialog::getOpenFileName(this, tr("Choose an FLM file to merge"), m_lastOpendir, tr("LuxRender FLM files (*.flm)"));
+
+	if(flmFileName.isNull())
+		return;
+
+	indicateActivity ();
+	statusMessage->setText("Merging FLM...");
+
+	// Start merge thread
+	m_mergeTimer->start(1000);
+
+	delete m_flmmergeThread;
+	m_flmmergeThread = new boost::thread(boost::bind(&MainWindow::flmMergeThread, this, flmFileName));
+}
+
 // Render menu slots
 void MainWindow::resumeRender()
 {
@@ -1105,6 +1136,10 @@
 			m_flmsaveThread->join();
 		delete m_flmsaveThread;
 		m_flmsaveThread = NULL;
+		if (m_flmmergeThread)
+			m_flmmergeThread->join();
+		delete m_flmmergeThread;
+		m_flmmergeThread = NULL;
 		if (m_updateThread)
 			m_updateThread->join();
 		delete m_updateThread;
@@ -1258,6 +1293,13 @@
 	qApp->postEvent(this, new QEvent((QEvent::Type)EVT_LUX_SAVEDFLM));
 }
 
+void MainWindow::flmMergeThread(QString filename)
+{
+	luxMergeFLM(qPrintable(filename));
+
+	qApp->postEvent(this, new QEvent((QEvent::Type)EVT_LUX_MERGEDFLM));
+}
+
 void MainWindow::batchProcessThread(QString inDir, QString outDir, QString outExtension, bool allLightGroups, bool asHDR)
 {
 	// Find 'flm' files in the input directory
@@ -1752,6 +1794,17 @@
 		m_flmsaveThread = NULL;
 		retval = TRUE;
 	}
+	else if (eventtype == EVT_LUX_MERGEDFLM) {
+		m_mergeTimer->stop();
+		statusMessage->setText("");
+		// reset progressindicator
+		indicateActivity(false);
+		if (m_flmmergeThread)
+			m_flmmergeThread->join();
+		delete m_flmmergeThread;
+		m_flmmergeThread = NULL;
+		retval = TRUE;
+	}
 	else if (eventtype == EVT_LUX_LOGEVENT) {
 		logEvent((LuxLogEvent *)event);
 		retval = TRUE;
diff -r 95f8ca75d1e0 qtgui/mainwindow.hxx
--- a/qtgui/mainwindow.hxx	Wed Jan 11 19:42:56 2012 +0100
+++ b/qtgui/mainwindow.hxx	Sat Jan 14 18:40:13 2012 -0700
@@ -312,9 +312,9 @@
 	
 	LuxGuiRenderState m_guiRenderState;
 	
-	QTimer *m_renderTimer, *m_statsTimer, *m_loadTimer, *m_saveTimer, *m_netTimer, *m_blinkTimer;
+	QTimer *m_renderTimer, *m_statsTimer, *m_loadTimer, *m_saveTimer, *m_mergeTimer, *m_netTimer, *m_blinkTimer;
 	
-	boost::thread *m_engineThread, *m_updateThread, *m_flmloadThread, *m_flmsaveThread, *m_batchProcessThread, *m_networkAddRemoveSlavesThread;
+	boost::thread *m_engineThread, *m_updateThread, *m_flmloadThread, *m_flmsaveThread, *m_flmmergeThread, *m_batchProcessThread, *m_networkAddRemoveSlavesThread;
 
 	bool openExrHalfFloats, openExrDepthBuffer;
 	int openExrCompressionType;
@@ -334,6 +334,7 @@
 	void updateThread();
 	void flmLoadThread(QString filename);
 	void flmSaveThread(QString filename);
+	void flmMergeThread(QString filename);
 	void batchProcessThread(QString inDir, QString outDir, QString outExtension, bool allLightGroups, bool asHDR);
 
 	enum { MaxRecentServers = 20 };
@@ -388,6 +389,7 @@
 	void resumeFLM ();
 	void loadFLM (QString flmFileName = QString());
 	void saveFLM ();
+	void mergeFLM (QString flmFileName = QString());
 	void resumeRender ();
 	void pauseRender ();
 	void stopRender ();