# Vwrays-Rtcontrib generated image agreement	with Rpict image

**URL:** <https://discourse.radiance-online.org/t/vwrays-rtcontrib-generated-image-agreement-with-rpict-image/2902>\
**Category:** radiance-general\
**Created:** [June 11, 2010, 7:51pm UTC](https://discourse.radiance-online.org/t/vwrays-rtcontrib-generated-image-agreement-with-rpict-image/2902 "2010-06-11T19:51:28Z")\
**Posts on this page:** 3\
**Page:** 1

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**Author:** ![Chris\_Humann](https://discourse.radiance-online.org/letter_avatar_proxy/v4/letter/c/90db22/32.png) [@Chris\_Humann](https://discourse.radiance-online.org/u/Chris_Humann)\
**Post date:** [June 11, 2010, 7:51pm UTC](https://discourse.radiance-online.org/t/vwrays-rtcontrib-generated-image-agreement-with-rpict-image/2902/1 "2010-06-11T19:51:28Z")

</div>

Hi all,

I've been using rtcontrib to look at different window contributions in a space under an overcast sky. When I 'pcomb' the resultant images and compare the illuminance values to an image generated with 'rad' I get light levels 1/3 of what I'm getting in the rad generated image.

For the rtcontrib routine I used:  
oconv mat.rad d\_cie.rad d\_c1.rad d\_c2.rad d\_c3.rad d\_c5.rad d\_c6.rad d\_c7.rad d\_c9.rad d\_c130.rad d\_c131.rad d\_c132.rad d\_c133.rad d\_c134.rad d\_c255.rad \> punch\_40.oct

vwrays -ff -x 1024 -y 1024 -vf plan\_1.vf | rtcontrib -ffc -I+ -V+ `vwrays -d -x 1024 -y 1024 -vf plan_1.vf` @options.opt -o images/plan1\_%s.pic -M glass.txt punch\_40.oct

The parameters set in the 'options.opt' file are:  
-n 2  
-ab 5  
-ad 8000  
-as 2000  
-ar 800  
-dt 0  
-dc 1  
-ds .2  
-lw .000001

the "glass.txt' file contains the different glass geometries:  
d\_c130  
d\_c131  
d\_c132  
d\_c133

For the 'pcomb' routine:  
pcomb -o plan\_1\_d\_c130.hdr -o plan\_1\_d\_c131.hdr -o plan\_1\_d\_c132.hdr -o plan\_1\_d\_c133.hdr \> plan\_1\_all\_glass.hdr

For the 'rad' routine:  
rpict -t 60 -vu 0 0 1 -vf plan\_1.vf -x 2700 -y 2700 -dp 4096 -ar 323 -ms 0.31 -ds .2 -dt .05 -dc .75 -dr 3 -sj 1 -st .01 -aa .1 -ad 1536 -as 768 -av 0 0 0 -lr 12 -lw .0005 -ab 3 -i -ps 3 -pt .04 -o plan\_1.unf d.oct

I'm sure I'm missing somethng, but am just not sure what.

Thanks!

Chris

Christian Humann ~ Associate  
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Alameda, CA 94501 USA  
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510 521 3800 VOICE  
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[www.coolshadow.com](http://www.coolshadow.com)

---

<div class="post-metadata">

**Author:** ![Greg\_Ward](https://discourse.radiance-online.org/user_avatar/discourse.radiance-online.org/greg_ward/32/471_2.png) [@Greg\_Ward](https://discourse.radiance-online.org/u/Greg_Ward)\
**Post date:** [June 11, 2010, 8:42pm UTC](https://discourse.radiance-online.org/t/vwrays-rtcontrib-generated-image-agreement-with-rpict-image/2902/2 "2010-06-11T20:42:59Z")

</div>

Hi Chris,

Could the -I+ option you're giving to rtcontrib be substituted with the -i+ option? The former would compute an array of irradiance values surrounding your -vp setting, rather than an irradiance image of intersected surfaces. I wouldn't think the images would look very similar in this case. Did you compare the appearance of rtcontrib -I+ versus rpict -i?

-Greg

> **···**
>
> > From: Chris Humann \<chris@coolshadow.com\>  
> > Date: June 11, 2010 12:51:28 PM PDT
> > 
> > Hi all,
> > 
> > I've been using rtcontrib to look at different window contributions in a space under an overcast sky. When I 'pcomb' the resultant images and compare the illuminance values to an image generated with 'rad' I get light levels 1/3 of what I'm getting in the rad generated image.
> > 
> > For the rtcontrib routine I used:  
> > oconv mat.rad d\_cie.rad d\_c1.rad d\_c2.rad d\_c3.rad d\_c5.rad d\_c6.rad d\_c7.rad d\_c9.rad d\_c130.rad d\_c131.rad d\_c132.rad d\_c133.rad d\_c134.rad d\_c255.rad \> punch\_40.oct
> > 
> > vwrays -ff -x 1024 -y 1024 -vf plan\_1.vf | rtcontrib -ffc -I+ -V+ `vwrays -d -x 1024 -y 1024 -vf plan_1.vf` @options.opt -o images/plan1\_%s.pic -M glass.txt punch\_40.oct
> > 
> > The parameters set in the 'options.opt' file are:  
> > -n 2  
> > -ab 5  
> > -ad 8000  
> > -as 2000  
> > -ar 800  
> > -dt 0  
> > -dc 1  
> > -ds .2  
> > -lw .000001
> > 
> > the "glass.txt' file contains the different glass geometries:  
> > d\_c130  
> > d\_c131  
> > d\_c132  
> > d\_c133
> > 
> > For the 'pcomb' routine:  
> > pcomb -o plan\_1\_d\_c130.hdr -o plan\_1\_d\_c131.hdr -o plan\_1\_d\_c132.hdr -o plan\_1\_d\_c133.hdr \> plan\_1\_all\_glass.hdr
> > 
> > For the 'rad' routine:  
> > rpict -t 60 -vu 0 0 1 -vf plan\_1.vf -x 2700 -y 2700 -dp 4096 -ar 323 -ms 0.31 -ds .2 -dt .05 -dc .75 -dr 3 -sj 1 -st .01 -aa .1 -ad 1536 -as 768 -av 0 0 0 -lr 12 -lw .0005 -ab 3 -i -ps 3 -pt .04 -o plan\_1.unf d.oct
> > 
> > I'm sure I'm missing somethng, but am just not sure what.
> > 
> > Thanks!
> > 
> > Chris

---

<div class="post-metadata">

**Author:** ![Chris\_Humann](https://discourse.radiance-online.org/letter_avatar_proxy/v4/letter/c/90db22/32.png) [@Chris\_Humann](https://discourse.radiance-online.org/u/Chris_Humann)\
**Post date:** [June 11, 2010, 10:37pm UTC](https://discourse.radiance-online.org/t/vwrays-rtcontrib-generated-image-agreement-with-rpict-image/2902/3 "2010-06-11T22:37:04Z")

</div>

Thanks Greg, that was the problem and the needle I was looking for. I don't think I would have figured that out anytime soon.

Best,  
Chris  
Christian Humann ~ Associate  
LOISOS + UBBELOHDE  
- - - - - - - - - - - - - - - - - - - - - - - - - - -  
1917 Clement Avenue Building 10A  
Alameda, CA 94501 USA  
- - - - - - - - - - - - - - - - - - - - - - - - - - -  
510 521 3800 VOICE  
510 521 3820 FAX  
- - - - - - - - - - - - - - - - - - - - - - - - - - -

> **[Loisos + Ubbelohde](https://coolshadow.com/)**
>
> Light, Energy, Environment. Loisos + Ubbelohde helps create high-performance buildings that deliver efficiency, comfort and delight.

> **···**
>
> On Jun 11, 2010, at 1:42 PM, Greg Ward wrote:
> 
> > Hi Chris,
> > 
> > Could the -I+ option you're giving to rtcontrib be substituted with the -i+ option? The former would compute an array of irradiance values surrounding your -vp setting, rather than an irradiance image of intersected surfaces. I wouldn't think the images would look very similar in this case. Did you compare the appearance of rtcontrib -I+ versus rpict -i?
> > 
> > -Greg
> > 
> > > From: Chris Humann \<chris@coolshadow.com\>  
> > > Date: June 11, 2010 12:51:28 PM PDT
> > > 
> > > Hi all,
> > > 
> > > I've been using rtcontrib to look at different window contributions in a space under an overcast sky. When I 'pcomb' the resultant images and compare the illuminance values to an image generated with 'rad' I get light levels 1/3 of what I'm getting in the rad generated image.
> > > 
> > > For the rtcontrib routine I used:  
> > > oconv mat.rad d\_cie.rad d\_c1.rad d\_c2.rad d\_c3.rad d\_c5.rad d\_c6.rad d\_c7.rad d\_c9.rad d\_c130.rad d\_c131.rad d\_c132.rad d\_c133.rad d\_c134.rad d\_c255.rad \> punch\_40.oct
> > > 
> > > vwrays -ff -x 1024 -y 1024 -vf plan\_1.vf | rtcontrib -ffc -I+ -V+ `vwrays -d -x 1024 -y 1024 -vf plan_1.vf` @options.opt -o images/plan1\_%s.pic -M glass.txt punch\_40.oct
> > > 
> > > The parameters set in the 'options.opt' file are:  
> > > -n 2  
> > > -ab 5  
> > > -ad 8000  
> > > -as 2000  
> > > -ar 800  
> > > -dt 0  
> > > -dc 1  
> > > -ds .2  
> > > -lw .000001
> > > 
> > > the "glass.txt' file contains the different glass geometries:  
> > > d\_c130  
> > > d\_c131  
> > > d\_c132  
> > > d\_c133
> > > 
> > > For the 'pcomb' routine:  
> > > pcomb -o plan\_1\_d\_c130.hdr -o plan\_1\_d\_c131.hdr -o plan\_1\_d\_c132.hdr -o plan\_1\_d\_c133.hdr \> plan\_1\_all\_glass.hdr
> > > 
> > > For the 'rad' routine:  
> > > rpict -t 60 -vu 0 0 1 -vf plan\_1.vf -x 2700 -y 2700 -dp 4096 -ar 323 -ms 0.31 -ds .2 -dt .05 -dc .75 -dr 3 -sj 1 -st .01 -aa .1 -ad 1536 -as 768 -av 0 0 0 -lr 12 -lw .0005 -ab 3 -i -ps 3 -pt .04 -o plan\_1.unf d.oct
> > > 
> > > I'm sure I'm missing somethng, but am just not sure what.
> > > 
> > > Thanks!
> > > 
> > > Chris
> > 
> > \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_  
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