[Radiance-general] Integrated photon mapping and material roughness

[Martin Klingler]

Hello experts,

 

playing around with the new integrated photon mapping I met the following strage effect.

 

First I am using the old version (Radiance 3.7 and Photon map patch 4.3.1) and this very simple geometry (sorry for the german notes):

 

# LED als IES-Verteilung

# strahlt in Richtung der x-Achse

!xform LED.rad | xform -ry -90 -t -0.2 0 0

 

# Umlenkspiegel als Metal

void metal spiegel

0

0

5

0.9 0.9 0.9 1 0

 

!gensurf spiegel mir ?-0.25+s*0.5? ?-0.25+t*0.5? ?0? 1 1 | xform -ry -135

 

# Testflaeche

void plastic weiss

0

0

5

0.8 0.8 0.8 0 0

 

!gensurf weiss test ?-4+s*8? ?-4+t*8? ?-2? 1 1

 

A caustic map is generated like this: mkpmap -apc map2 1000000 -dp 50000

 

And based on that rad file:

 

# Rad Input File created by trad Son Aug  2 11:57:29 CEST 2015

DETAIL= Medium

EYESEP= 1

INDIRECT= 1

OCTREE= Dir_Pmap.oct

PENUMBRAS= True

PICTURE= Dir_Pmap

QUALITY= Medium

RESOLUTION= 1024

UP= Z

VARIABILITY= High

ZONE= Interior -4 4 -4 4 -2 0.5

render= -apcb map2 100 2000

scene= System_Pmap.rad

view= g1 -vtl -vp 0 0 -0.5 -vd 0 0 -1 -vu 0 1 0 -vh 8.5 -vv 8.5

 

I get this output: https://dl.dropboxusercontent.com/u/27495200/HGF.jpg

 

If I change the roughness for the "spiegel" material to 0.1, I get this output: https://dl.dropboxusercontent.com/u/27495200/RoughF.jpg

which seem to be quite Ok for me.

 

Now I change to the radiance HEAD from the 4th July. I use the same geometry and the following rad file:

 

# Rad Input File created by trad Son Aug  2 11:59:05 CEST 2015

DETAIL= Medium

INDIRECT= 0

OCTREE= Pmap1.oct

PCMAP= map3 1000000 50

PENUMBRAS= True

PICTURE= Pmap1rough

QUALITY= Medium

RESOLUTION= 1024

UP= Z

VARIABILITY= High

ZONE= Interior -4 4 -4 4 -2 0.5

mkpmap= -dp 50000

scene= System_Pmap.rad

view= g1 -vtl -vp 0 0 -0.5 -vd 0 0 -1 -vu 0 1 0 -vh 8.5 -vv 8.5

 

With the roughness of 0.0 I get this output: https://dl.dropboxusercontent.com/u/27495200/HGnF.jpg

Which, compared to a run with mirror material, seems to be even better than the old result.

 

But when I change to the roughness 0.1 I get this output: https://dl.dropboxusercontent.com/u/27495200/RoughnF.jpg

 

I already tried differend setting for the bandwidth parameter but the were no fundamental chages.

 

May thanks for any ideas

Martin Klingler

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