[Radiance-general] rtcontrib issue (stuck on p.16 of understanding rtcontrib tutorial)

[Ji Zhang]

Dear list, following Kyle's post:

I was trying to render an image for the view from the back of the room
regarding the contribution from each of the 145 sky patches (Axel's
tutorial pp. 17)

The 146 individual sky patches hdr sterographic images are stored in the
"145_patches_rcontrib" directory.

Then I ran the following bash shell script:

DIMS=600
vw="-x $DIMS -y $DIMS -vf ./views/back.vf"
vwrays -ff $vw | rcontrib -bn 146 @./rtc.opt \
-fo -ffc $(vwrays -d $vw) -f tregenza.cal -b tbin \
-o ./145_patches_rcontrib/p%03d.hdr -m sky_glow \
-w ./testroom_whitesky.oct

Each of the 146 sky patch hdr images was replaced by a room view rendering.
However, some of the hdr images seem to have problem and can't be open with
PhotoSphere, such as p001-008, p024-038, p054-066, p080-090, p104-113,
p123-129, p137-140, and p144

May I ask if this is because no contribution from these specific sky
patches to the visible surfaces can be identified from this point of view
at the back of the room (e.g. the sky patch is "behind" the vertical window
plane judging from the change of the shadow pattern of the renderings) ?

Thanks!
- Ji


On Sun, Jul 1, 2012 at 7:37 AM, kyle konis <kskonis at gmail.com> wrote:

> I have added the -bn option and now have a good batch of sky subdivisions.
>
> vwrays -ff $vw | rtcontrib -bn 146 @rtc.opt -ffc \
> $(vwrays -d $vw) -V+ -f tregenza.cal -b tbin  \
> -o images/patches/p%03d.hdr \
> -m sky_glow testroom_whitesky.oct
>
> and a nice visualization with Andy's previous response to Ji:
>
> cnt 146 | rcalc -e '$1=rand(recno);$2=rand(recno+.3);$3=rand(recno+.7)' | \
> dctimestep ./images/patches/p%03d.hdr > ./images/sky_colorcomb.hdr
>
>
> ...
>
> I am still a bit confused regarding patch p000.hdr
>
> When i attempt to open in Photosphere, i get :  "Cannot map HDR pixels
> in MapSubimage"
>
> Since the sky only needs 145 patches, the purpose of this p000.hdr is
> a mystery.  (Although i recall reading something about is purpose late
> last night . . .  a placeholder for the ground reflection if it is
> added  . . . ?)
>
>
> -Kyle
>
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