diff --git a/cellular/Makefile b/cellular/Makefile
index 89967d8..a706a84 100755
--- a/cellular/Makefile
+++ b/cellular/Makefile
@@ -1,92 +1,110 @@
 # Makefile (for gnumake) to translate OBJ files to Radiance octree representing
 # an exemplary model of a cellular office (one work desk with small meeting
 # desk) as a realistic setting for daylight simulation.
 
 # Modelling and assignment of material names in Blender, export to Wavefront OBJ.
 # Furniture is modelled by collections in Blender with marker triangles for
 # replmarks, these get material <object>Marker with <object>.obj being the file-
 # name of the exported, detailed geometry. The latter are exported with the main
 # model but mapped to void by obj2rad.
 
 # Oct 2020, Lars O. Grobe <larsoliver.grobe@hslu.ch>
 # Lucerne University of Applied Sciences and Arts HSLU, Switzerland
 
 # This work is licensed under a Creative Commons Attribution 4.0 International
 # License: https://creativecommons.org/licenses/by/4.0/
 
 # Begin model configuration ====================================================
 
 # Name of this model, will be used to name scene files
 name = Cellular
 
+# Switch artificial lighting on (<0) or off (=0)
+export lighting=0
+
 # Glazing definition
 # Overwrite default (red, green, blue) properties of window groups by defining
 # wgTopMat, wgMiddleMat, wgBottoMat and point variable to the file here
 glazingMat = glazingMatDef.mat
 
 # Sky definition
 # Overwrite default by given file
 sky = skies/skyDef.sky
 
 # Radiance object files to be included by xform (use only for simple geometries)
 objects = desk.rad locker.rad sideBoard.rad lamp.rad workstation.rad
 
 # Radiance meshes to be compiled from Wavefront OBJs
 meshes = chair1.rtm chair2.rtm poster1.rtm poster2.rtm
 
+# Number of processort cores / parallel processes to fork
+NCPU=1
+
 # End model configuration ======================================================
 
+# Main scene file, may contain triangular markers processed by replmarks
+octree = $(name).oct
+scene = $(name).rad
+ambfile = $(name).amb
+unffile = $(name).unf
+
 # view for test
 rvuview = -vtv -vp -1.2 .2 1.7 -vd .5 1 0 -vh 90 -vv 75 # perspective
         # -vta -vp 0 .1 1.7 -vd 0 1 0 -vh 180 -vv 180   # fisheye
+
 # render settings for test
-rvuopt = -n 4  -ab 2 -ad 1024 -as 512 -aa .15 -st 0 -ss 16 -lw 2e-3
+rvuopt = -n $(NCPU)  -ab 2 -ad 1024 -as 512 -aa .15 -st 0 -ss 16 -lw 2e-3
 
-# Main scene file, may contain triangular markers processed by replmarks
-octree = $(name).oct
-scene = $(name).rad
+# view for unfiltered HDR
+rtpictview = -vta -vp .25 1.5 1.45 -vd 1 0 0 -vh 180 -vv 180
+
+# render settings for unfiltered HDR
+rtpictopt = -n $(NCPU) -ab 3 -ad 2048 -as 1024 -aa .1 -st 0 -ss 16 -lw 1e-4 -af $(ambfile) -x 2400 -y 2400
 
 # markers must be have modifier name <mesh>Marker, where <mesh> is the basenam
 # of the compiled mesh (without suffix .rtm)
 meshMarkers := $(foreach mesh, $(meshes),-I $(mesh) $(subst .rtm,Marker,$(mesh)))
 objectMarkers := $(foreach object, $(objects),-x $(object) $(subst .rad,Marker,$(object)))
 replmarksStr = $(meshMarkers) $(objectMarkers)
 
 # Complete RAYPATH variable
 myRAYPATH = $(RAYPATH):$(glazingPath)
 
 vpath %.obj obj   # Wavefront OBJ files
 vpath %.map mat   # Mapping from Wavefront materials to Radiance modifiers
 vpath %.mat mat   # Radiance modifiers
 vpath %.sky skies # Sky desciptions
 
 # recipes from here
 .PHONY: clean debug octree
 
 # default target
 debug : $(octree)
 	RAYPATH=$(myRAYPATH); rvu $(rvuopt) $(rvuview) $<
-	@echo "Done."
 
 octree : $(octree)
 
+unf : $(octree)
+	RAYPATH=$(myRAYPATH); rtpict $(rtpictopt) $(rtpictview) -x 64 -y 64 $< > /dev/null
+	RAYPATH=$(myRAYPATH); rtpict $(rtpictopt) $(rtpictview) $< > $(unffile)
+
 # Convert scene and replace markers by objects or meshes
 $(scene) : %.rad : %.mat $(glazingMat) %.map %.obj $(meshes) $(objects)
 	cat $< $(word 2, $^) > $@
 	obj2rad -m $(word 3, $^) $(word 4, $^) | replmarks $(replmarksStr) >> $@
 
 # Convert Wavefront OBJs to Radiance meshes
 %.rtm : %.mat %.obj
 	obj2mesh -w -a $^ $@
 
 # Convert Wavefront OBJs to Radiance objects
 $(objects) : %.rad : %.mat %.obj
 	cat $< > $@
 	obj2rad  $(lastword $^) >> $@
 
 # Compile scene into octree
 $(octree) : $(scene) $(sky)
 	oconv $^ > $@
 
 clean :
-	rm -f $(meshes) $(objects) $(scene) $(octree)
+	rm -f $(meshes) $(objects) $(scene) $(octree) $(ambfile)
diff --git a/cellular/mat/lamp.mat b/cellular/mat/lamp.mat
index c64e4bf..a325327 100644
--- a/cellular/mat/lamp.mat
+++ b/cellular/mat/lamp.mat
@@ -1,17 +1,13 @@
 void metal lampFrameMat
 0
 0
 5	.6	.6	.6
 	.3	.02
 
 void plastic lampGlassMat
 0
 0
 5	.6	.6	.6
 	.3	0
 
-void glow lampGlassMat
-0
-0
-4	10	10	10
-	0
+! ((lighting)) && echo "void glow lampGlassMat 0 0 4 10 10 10 0"