diff --git a/csgterm.cc b/csgterm.cc
index 826ec440..c1c6e14a 100644
--- a/csgterm.cc
+++ b/csgterm.cc
@@ -164,3 +164,45 @@ QString CSGTerm::dump()
 		return QString("(%1 - %2)").arg(left->dump(), right->dump());
 	return label;
 }
+
+CSGChain::CSGChain()
+{
+}
+
+void CSGChain::add(PolySet *polyset, CSGTerm::type_e type, QString label)
+{
+	polysets.append(polyset);
+	types.append(type);
+	labels.append(label);
+}
+
+void CSGChain::import(CSGTerm *term, CSGTerm::type_e type)
+{
+	if (term->type == CSGTerm::PRIMITIVE) {
+		add(term->polyset, type, term->label);
+	} else {
+		import(term->left, type);
+		import(term->right, term->type);
+	}
+}
+
+QString CSGChain::dump()
+{
+	QString text;
+	for (int i = 0; i < types.size(); i++)
+	{
+		if (types[i] == CSGTerm::UNION) {
+			if (i != 0)
+				text += "\n";
+			text += "+";
+		}
+		if (types[i] == CSGTerm::DIFFERENCE)
+			text += " -";
+		if (types[i] == CSGTerm::INTERSECTION)
+			text += " *";
+		text += labels[i];
+	}
+	text += "\n";
+	return text;
+}
+
diff --git a/glview.cc b/glview.cc
index 3260645f..b6132536 100644
--- a/glview.cc
+++ b/glview.cc
@@ -47,6 +47,19 @@ void GLView::initializeGL()
 	glDepthRange(-FAR_FAR_AWAY, +FAR_FAR_AWAY);
 
 	glClearColor(1.0, 1.0, 0.9, 0.0);
+
+#if 0
+	GLfloat light_diffuse[] = {1.0, 1.0, 1.0, 1.0};
+	GLfloat light_position[] = {1.0, 1.0, -1.0, 0.0};
+
+	glLightfv(GL_LIGHT0, GL_DIFFUSE, light_diffuse);
+	glLightfv(GL_LIGHT0, GL_POSITION, light_position);
+	glEnable(GL_LIGHT0);
+
+	glColorMaterial(GL_FRONT_AND_BACK, GL_AMBIENT_AND_DIFFUSE);
+	glEnable(GL_COLOR_MATERIAL);
+	glEnable(GL_LIGHTING);
+#endif
 }
 
 void GLView::resizeGL(int w, int h)
@@ -56,7 +69,7 @@ void GLView::resizeGL(int w, int h)
 
 void GLView::paintGL()
 {
-	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
+	glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT | GL_STENCIL_BUFFER_BIT);
 
 	glMatrixMode(GL_PROJECTION);
 	glLoadIdentity();
@@ -68,7 +81,10 @@ void GLView::paintGL()
 	glRotated(object_rot_y, 1.0, 0.0, 0.0);
 	glRotated(object_rot_z, 0.0, 0.0, 1.0);
 
+	glDepthFunc(GL_LESS);
+
 #if 0
+	glLineWidth(1);
 	glColor3d(0.0, 0.0, 1.0);
 	glBegin(GL_LINES);
 	glVertex3d(0, 0, 0); glVertex3d(10, 0, 0);
@@ -77,6 +93,7 @@ void GLView::paintGL()
 	glEnd();
 #endif
 
+	glLineWidth(5);
 	glColor3d(1.0, 0.0, 0.0);
 
 	if (renderfunc)
diff --git a/mainwin.cc b/mainwin.cc
index 67a757fa..55e29142 100644
--- a/mainwin.cc
+++ b/mainwin.cc
@@ -37,6 +37,7 @@ MainWindow::MainWindow(const char *filename)
 	root_node = NULL;
 	root_raw_term = NULL;
 	root_norm_term = NULL;
+	root_chain = NULL;
 #ifdef ENABLE_CGAL
 	root_N = NULL;
 #endif
@@ -82,8 +83,8 @@ MainWindow::MainWindow(const char *filename)
 		actViewModeCGALSurface->setCheckable(true);
 		actViewModeCGALGrid->setCheckable(true);
 #endif
-		actViewModeTrownTogether = menu->addAction("Thrown Together", this, SLOT(viewModeTrownTogether()));
-		actViewModeTrownTogether->setCheckable(true);
+		actViewModeThrownTogether = menu->addAction("Thrown Together", this, SLOT(viewModeThrownTogether()));
+		actViewModeThrownTogether->setCheckable(true);
 
 		menu->addSeparator();
 		menu->addAction("Top");
@@ -137,7 +138,7 @@ MainWindow::MainWindow(const char *filename)
 #ifdef ENABLE_OPENCSG
 	viewModeOpenCSG();
 #else
-	viewModeTrownTogether();
+	viewModeThrownTogether();
 #endif
 
 	setCentralWidget(s1);
@@ -267,6 +268,11 @@ void MainWindow::actionCompile()
 		root_norm_term = NULL;
 	}
 
+	if (root_chain) {
+		delete root_chain;
+		root_chain = NULL;
+	}
+
 	root_norm_term = root_raw_term->link();
 
 	while (1) {
@@ -282,6 +288,9 @@ void MainWindow::actionCompile()
 		return;
 	}
 
+	root_chain = new CSGChain();
+	root_chain->import(root_norm_term);
+
 	console->append("Compilation finished.");
 }
 
@@ -296,23 +305,6 @@ static void report_func(const class AbstractNode*, void *vp, int mark)
         m->console->append(msg);
 }
 
-#include <CGAL/Nef_3/OGL_helper.h>
-
-static void renderGLviaCGAL(void *vp)
-{
-	MainWindow *m = (MainWindow*)vp;
-	if (m->root_N) {
-		CGAL::OGL::Polyhedron P;
-		CGAL::OGL::Nef3_Converter<CGAL_Nef_polyhedron>::convert_to_OGLPolyhedron(*m->root_N, &P);
-		P.init();
-		if (m->actViewModeCGALSurface->isChecked())
-			P.set_style(CGAL::OGL::SNC_BOUNDARY);
-		if (m->actViewModeCGALGrid->isChecked())
-			P.set_style(CGAL::OGL::SNC_SKELETON);
-		P.draw();
-	}
-}
-
 void MainWindow::actionRenderCGAL()
 {
 	actionCompile();
@@ -356,7 +348,7 @@ void MainWindow::actionDisplayCSGTree()
 {
 	QTextEdit *e = new QTextEdit(NULL);
 	e->setTabStopWidth(30);
-	e->setWindowTitle("CSG Dump");
+	e->setWindowTitle("CSG Tree Dump");
 	if (root_node) {
 		e->setPlainText(root_node->dump(""));
 	} else {
@@ -370,8 +362,8 @@ void MainWindow::actionDisplayCSGProducts()
 {
 	QTextEdit *e = new QTextEdit(NULL);
 	e->setTabStopWidth(30);
-	e->setWindowTitle("CSG Dump");
-	e->setPlainText(QString("\nCSG before normalization:\n%1\n\n\nCSG after normalization:\n%2\n").arg(root_raw_term ? root_raw_term->dump() : "N/A", root_norm_term ? root_norm_term->dump() : "N/A"));
+	e->setWindowTitle("CSG Products Dump");
+	e->setPlainText(QString("\nCSG before normalization:\n%1\n\n\nCSG after normalization:\n%2\n\n\nCSG rendering chain:\n%3\n").arg(root_raw_term ? root_raw_term->dump() : "N/A", root_norm_term ? root_norm_term->dump() : "N/A", root_chain ? root_chain->dump() : "N/A"));
 	e->show();
 	e->resize(600, 400);
 }
@@ -395,17 +387,79 @@ void MainWindow::viewModeActionsUncheck()
 	actViewModeCGALSurface->setChecked(false);
 	actViewModeCGALGrid->setChecked(false);
 #endif
-	actViewModeTrownTogether->setChecked(false);
+	actViewModeThrownTogether->setChecked(false);
 }
 
 #ifdef ENABLE_OPENCSG
 
+#include <GL/glut.h>
+
+class DLPrim : public OpenCSG::Primitive
+{
+public:
+	DLPrim(unsigned int displayListId, OpenCSG::Operation operation, unsigned int convexity) :
+			OpenCSG::Primitive(operation, convexity), id(displayListId) { }
+	virtual void render() { glCallList(id); }
+	unsigned int id;
+};
+
+static void renderGLviaOpenCSG(void *vp)
+{
+	MainWindow *m = (MainWindow*)vp;
+	static int glew_initialized = 0;
+	if (!glew_initialized) {
+		glew_initialized = 1;
+		glewInit();
+	}
+	if (m->root_chain) {
+		glDepthFunc(GL_LEQUAL);
+		/* FIXME */
+		for (int i = 0; i < m->root_chain->polysets.size(); i++) {
+			if (m->root_chain->types[i] == CSGTerm::DIFFERENCE) {
+				m->root_chain->polysets[i]->render_surface(PolySet::COLOR_CUTOUT);
+				m->root_chain->polysets[i]->render_edges(PolySet::COLOR_CUTOUT);
+			} else {
+				m->root_chain->polysets[i]->render_surface(PolySet::COLOR_MATERIAL);
+				m->root_chain->polysets[i]->render_edges(PolySet::COLOR_MATERIAL);
+			}
+		}
+	} else {
+		GLuint id1 = glGenLists(1);
+		glNewList(id1, GL_COMPILE);
+		glutSolidCube(1.8);
+		glEndList();
+
+		GLuint id2 = glGenLists(1);
+		glNewList(id2, GL_COMPILE);
+		glutSolidSphere(1.2, 20, 20);
+		glEndList();
+
+		DLPrim* box = new DLPrim(id1, OpenCSG::Intersection, 1);
+		DLPrim* sphere = new DLPrim(id2, OpenCSG::Subtraction, 1);
+		std::vector<OpenCSG::Primitive*> primitives;
+
+		primitives.push_back(box);
+		primitives.push_back(sphere);
+
+		OpenCSG::render(primitives, OpenCSG::Goldfeather, OpenCSG::NoDepthComplexitySampling);
+
+		glDepthFunc(GL_EQUAL);
+		glColor3f(1.0, 0, 0);
+		for (unsigned int i = 0; i < primitives.size(); i++) {
+			primitives[i]->render();
+			glDeleteLists(((DLPrim*)primitives[i])->id, 1);
+			delete primitives[i];
+		}
+		glDepthFunc(GL_LESS);
+	}
+}
+
 void MainWindow::viewModeOpenCSG()
 {
-	/* FIXME */
 	viewModeActionsUncheck();
 	actViewModeOpenCSG->setChecked(true);
-	screen->renderfunc = NULL;
+	screen->renderfunc = renderGLviaOpenCSG;
+	screen->renderfunc_vp = this;
 	screen->updateGL();
 }
 
@@ -413,6 +467,23 @@ void MainWindow::viewModeOpenCSG()
 
 #ifdef ENABLE_CGAL
 
+#include <CGAL/Nef_3/OGL_helper.h>
+
+static void renderGLviaCGAL(void *vp)
+{
+	MainWindow *m = (MainWindow*)vp;
+	if (m->root_N) {
+		CGAL::OGL::Polyhedron P;
+		CGAL::OGL::Nef3_Converter<CGAL_Nef_polyhedron>::convert_to_OGLPolyhedron(*m->root_N, &P);
+		P.init();
+		if (m->actViewModeCGALSurface->isChecked())
+			P.set_style(CGAL::OGL::SNC_BOUNDARY);
+		if (m->actViewModeCGALGrid->isChecked())
+			P.set_style(CGAL::OGL::SNC_SKELETON);
+		P.draw();
+	}
+}
+
 void MainWindow::viewModeCGALSurface()
 {
 	viewModeActionsUncheck();
@@ -433,28 +504,28 @@ void MainWindow::viewModeCGALGrid()
 
 #endif /* ENABLE_CGAL */
 
-static void renderGLTrownTogether_worker(CSGTerm *t)
-{
-	if (t->left)
-		renderGLTrownTogether_worker(t->left);
-	if (t->right)
-		renderGLTrownTogether_worker(t->right);
-	if (t->polyset)
-		t->polyset->render_opengl();
-}
-
-static void renderGLTrownTogether(void *vp)
+static void renderGLThrownTogether(void *vp)
 {
 	MainWindow *m = (MainWindow*)vp;
-	if (m->root_raw_term)
-		renderGLTrownTogether_worker(m->root_raw_term);
+	if (m->root_chain) {
+		glDepthFunc(GL_LEQUAL);
+		for (int i = 0; i < m->root_chain->polysets.size(); i++) {
+			if (m->root_chain->types[i] == CSGTerm::DIFFERENCE) {
+				m->root_chain->polysets[i]->render_surface(PolySet::COLOR_CUTOUT);
+				m->root_chain->polysets[i]->render_edges(PolySet::COLOR_CUTOUT);
+			} else {
+				m->root_chain->polysets[i]->render_surface(PolySet::COLOR_MATERIAL);
+				m->root_chain->polysets[i]->render_edges(PolySet::COLOR_MATERIAL);
+			}
+		}
+	}
 }
 
-void MainWindow::viewModeTrownTogether()
+void MainWindow::viewModeThrownTogether()
 {
 	viewModeActionsUncheck();
-	actViewModeTrownTogether->setChecked(true);
-	screen->renderfunc = renderGLTrownTogether;
+	actViewModeThrownTogether->setChecked(true);
+	screen->renderfunc = renderGLThrownTogether;
 	screen->renderfunc_vp = this;
 	screen->updateGL();
 }
diff --git a/openscad.h b/openscad.h
index e9a7455c..e62e79c9 100644
--- a/openscad.h
+++ b/openscad.h
@@ -31,6 +31,11 @@ static inline uint qHash(double v) {
 	return x.u[0] ^ x.u[1];
 }
 
+#ifdef ENABLE_OPENCSG
+// this must be included before the GL headers
+#  include <GL/glew.h>
+#endif
+
 #include <QHash>
 #include <QVector>
 #include <QMainWindow>
@@ -59,8 +64,9 @@ class ModuleInstanciation;
 class Module;
 
 class Context;
-class CSGTerm;
 class PolySet;
+class CSGTerm;
+class CSGChain;
 class AbstractNode;
 class AbstractPolyNode;
 
@@ -274,6 +280,10 @@ typedef CGAL_Nef_polyhedron::Point_3 CGAL_Point;
 
 #endif /* ENABLE_CGAL */
 
+#ifdef ENABLE_OPENCSG
+#  include <opencsg.h>
+#endif
+
 class PolySet
 {
 public:
@@ -291,14 +301,20 @@ public:
 	void append_vertex(double x, double y, double z);
 	void insert_vertex(double x, double y, double z);
 
-	void render_opengl() const;
+	enum colormode_e {
+		COLOR_NONE,
+		COLOR_MATERIAL,
+		COLOR_CUTOUT
+	};
+
+	void render_surface(colormode_e colormode) const;
+	void render_edges(colormode_e colormode) const;
 
 #ifdef ENABLE_CGAL
 	CGAL_Nef_polyhedron render_cgal_nef_polyhedron() const;
 #endif
 };
 
-#ifdef ENABLE_OPENCSG
 class CSGTerm
 {
 public:
@@ -327,7 +343,20 @@ public:
 	void unlink();
 	QString dump();
 };
-#endif
+
+class CSGChain
+{
+public:
+	QVector<PolySet*> polysets;
+	QVector<CSGTerm::type_e> types;
+	QVector<QString> labels;
+
+	CSGChain();
+
+	void add(PolySet *polyset, CSGTerm::type_e type, QString label);
+	void import(CSGTerm *term, CSGTerm::type_e type = CSGTerm::UNION);
+	QString dump();
+};
 
 class AbstractNode
 {
@@ -346,9 +375,7 @@ public:
 #ifdef ENABLE_CGAL
 	virtual CGAL_Nef_polyhedron render_cgal_nef_polyhedron() const;
 #endif
-#ifdef ENABLE_OPENCSG
 	virtual CSGTerm *render_csg_term(double m[16]) const;
-#endif
 	virtual QString dump(QString indent) const;
 };
 
@@ -363,9 +390,7 @@ public:
 #ifdef ENABLE_CGAL
 	virtual CGAL_Nef_polyhedron render_cgal_nef_polyhedron() const;
 #endif
-#ifdef ENABLE_OPENCSG
 	virtual CSGTerm *render_csg_term(double m[16]) const;
-#endif
 };
 
 extern int progress_report_count;
@@ -428,6 +453,7 @@ public:
 	AbstractNode *root_node;
 	CSGTerm *root_raw_term;
 	CSGTerm *root_norm_term;
+	CSGChain *root_chain;
 #ifdef ENABLE_CGAL
 	CGAL_Nef_polyhedron *root_N;
 #endif
@@ -460,7 +486,7 @@ public:
 	QAction *actViewModeCGALSurface;
 	QAction *actViewModeCGALGrid;
 #endif
-	QAction *actViewModeTrownTogether;
+	QAction *actViewModeThrownTogether;
 	void viewModeActionsUncheck();
 
 private slots:
@@ -471,7 +497,7 @@ private slots:
 	void viewModeCGALSurface();
 	void viewModeCGALGrid();
 #endif
-	void viewModeTrownTogether();
+	void viewModeThrownTogether();
 };
 
 extern AbstractModule *parse(const char *text, int debug);
diff --git a/openscad.pro b/openscad.pro
index 30caf29e..ed4618e5 100644
--- a/openscad.pro
+++ b/openscad.pro
@@ -6,7 +6,7 @@ DEFINES += "ENABLE_CGAL=1"
 LIBS += -lCGAL -lmpfr
 
 DEFINES += "ENABLE_OPENCSG=1"
-LIBS += -lopencsg -lGLEW
+LIBS += -lopencsg -lGLEW -lglut
 
 LEXSOURCES += lexer.l
 YACCSOURCES += parser.y
diff --git a/polyset.cc b/polyset.cc
index a60828b5..63d8514e 100644
--- a/polyset.cc
+++ b/polyset.cc
@@ -41,8 +41,12 @@ void PolySet::insert_vertex(double x, double y, double z)
 	polygons.last().insert(0, Point(x, y, z));
 }
 
-void PolySet::render_opengl() const
+void PolySet::render_surface(colormode_e colormode) const
 {
+	if (colormode == COLOR_MATERIAL)
+		glColor3ub(249, 215, 44);
+	if (colormode == COLOR_CUTOUT)
+		glColor3ub(157, 203, 81);
 	for (int i = 0; i < polygons.size(); i++) {
 		const Polygon *poly = &polygons[i];
 		glBegin(GL_POLYGON);
@@ -54,6 +58,23 @@ void PolySet::render_opengl() const
 	}
 }
 
+void PolySet::render_edges(colormode_e colormode) const
+{
+	if (colormode == COLOR_MATERIAL)
+		glColor3ub(255, 236, 94);
+	if (colormode == COLOR_CUTOUT)
+		glColor3ub(171, 216, 86);
+	for (int i = 0; i < polygons.size(); i++) {
+		const Polygon *poly = &polygons[i];
+		glBegin(GL_LINE_STRIP);
+		for (int j = 0; j < poly->size(); j++) {
+			const Point *p = &poly->at(j);
+			glVertex3d(p->x, p->y, p->z);
+		}
+		glEnd();
+	}
+}
+
 #ifdef ENABLE_CGAL
 
 class CGAL_Build_PolySet : public CGAL::Modifier_base<CGAL_HDS>