[Radiance-general] Radiance-general Digest, Vol 125, Issue 3
María Beatriz Piderit
beapiderit at gmail.com
Wed Jul 2 15:31:22 PDT 2014
Dear Kyle,
I downloaded the file that was in the link you attached for rendering hdr sky images. I tried it with two of my images, the first was a clear sky and the other one was an overcast sky.
With the overcast sky I didn't had any problems, it rendered fine, although the clear sky image render didn't come out well. There are two issues: the first is that in the HDR images the sky appears really dark, and in the TIFF image the sky looks good but the ground disappears.
Could you give me some tips to improve the clear sky images? Have you had this problem when dealing with a clear sky render?
This is the link where you can see the results: https://www.dropbox.com/sh/ujhiskn9ohks3vt/AAAjkOyAis6_MfCEHfXwwalea
Best,
M. Beatriz Piderit M.
Arquitecta UBB, MA, PhD UC Louvain
Departamento Diseño y Teoría de la Arquitectura
Universidad del Bio-Bio Concepción, Chile
El 01-07-2014, a las 19:10, radiance-general-request at radiance-online.org escribió:
> Send Radiance-general mailing list submissions to
> radiance-general at radiance-online.org
>
> To subscribe or unsubscribe via the World Wide Web, visit
> http://www.radiance-online.org/mailman/listinfo/radiance-general
> or, via email, send a message with subject or body 'help' to
> radiance-general-request at radiance-online.org
>
> You can reach the person managing the list at
> radiance-general-owner at radiance-online.org
>
> When replying, please edit your Subject line so it is more specific
> than "Re: Contents of Radiance-general digest..."
>
>
> Today's Topics:
>
> 1. Re: HDR Sky Camera @ LBNL's Flexlab (Kyle Konis)
>
>
> ----------------------------------------------------------------------
>
> Message: 1
> Date: Tue, 1 Jul 2014 16:10:29 -0700
> From: Kyle Konis <kskonis at gmail.com>
> To: Radiance general discussion <radiance-general at radiance-online.org>
> Subject: Re: [Radiance-general] HDR Sky Camera @ LBNL's Flexlab
> Message-ID:
> <CAAzVHq2LfEF7k1q2Asexzh4Du-jeTJd_pfqB4SUZ4BO1x=hiXQ at mail.gmail.com>
> Content-Type: text/plain; charset="utf-8"
>
> Following up here, (and on the referenced thread from about a year ago), i
> did succeed in rendering some simple Radiance objects with HDR skies.
>
> I have uploaded an example video here with the LBNL Skycam images (June 21,
> 2014 until about 10:40 AM) which was all I could process during the world
> cup match:
> http://performance-and-form.com/projects/rendering-digital-objects-with-high-dynamic-range-hdr-sky-images/
>
> Thanks are due to Coralie Cauwerts for corresponding to provide me with the
> proper .cal file for mapping hemispherical (rather than spherical) images.
>
> The skies are used to render a chrome sphere sitting on a pedestal. You can
> tell it is not a real object because it is outside for several hours and no
> birds sit or poop on it. (Good luck HDR Skycam ! )
>
> I have zipped all the files used to make the video and put them on the page
> for download, as well as a few experiments i have made in manipulating
> surfaces (either transmission or shading) in response to sky data from
> Portland, Oregon using a Canon A570 with Stereo Data Maker used to automate
> bracketed image acquisition (i have a plan to post the details for that, as
> it is a very low-cost < $80 approach and will get to it).
>
> let me know (offline) if there are issues downloading or executing the
> files,
>
> best,
>
> -Kyle
>
> -----------------------------------------------
> Kyle Konis, AIA, Ph.D
> Assistant Professor
> School of Architecture, WAH 204
> University of Southern California
> Los Angeles, CA 90089-0291
> http://arch.usc.edu/faculty/kkonis
> -----------------------------------------------
>
>
>
>
>
>
>
> On Tue, Jul 1, 2014 at 8:52 AM, Christian Humann <chris at christianhumann.com>
> wrote:
>
>> Hi Joe,
>>
>> Thank you for the references.
>>
>> The HDR image by default is co-planar with the x and z axis with its
>> surface normal pointing in the negative y direction. You'll need to
>> translate the image so that its surface normal is pointed down along the
>> negative z axis and rotate it so that North is up when looking up towards
>> zenith.
>>
>> The groundglow description is actually not necessary and has no effect. If
>> you wanted to define the ground for inclusion in a scene you could use the
>> following:
>>
>> void glow groundglow
>> 0
>> 0
>> 4 .15 .15 .15 0 #(.15 .15 .15 = RGB values for the ground material)
>>
>> groundglow source ground
>> 0
>> 0
>> 4 0 0 -1 180
>>
>>
>> I too have been getting lower values than the measured global horizontal
>> illuminance. I think the suggestions made made by Rob and Greg about using
>> mksource and adjusting the subtended angle of the solar source may be the
>> solution. Not sure yet how to implement the latter but I will certainly
>> keep you posted.
>>
>> Cheers,
>> Chris
>>
>> On Jun 30, 2014, at 10:26 PM, Joe Smith <the.oat.cracker at gmail.com> wrote:
>>
>> Hi Chris,
>>
>> Thank you very much for your reply, especially for reminding me the
>> conversion of the unit between foot candela and lux!
>>
>> May I ask the following questions?
>>
>> 1. why the hdr fisheye image needs to be rotated along x axis for 90
>> degrees and along z axis for 180 degrees? using the fisheye.cal file as
>> reference when defining the colorpict "skypict"?
>>
>> 2. why "skypict is used as a modifier to define the "glow" material
>> "groundglow"? I thought usually this position is set as "void"
>>
>>
>> Using your approach, I tried some other hdr image provided by your
>> project, and it seems the global horizontal illuminance is always
>> underestimated as compared to the one reported in the csv file.
>>
>> rubbing my head about this issue, and advices are greatly appreciated!
>>
>> Regards,
>> Joe
>>
>>
>>
>> On Tue, Jul 1, 2014 at 3:06 AM, Christian Humann <
>> chris at christianhumann.com> wrote:
>>
>>> Hi Joe,
>>>
>>> The global values in the CSV file are in footcandles so you will need to
>>> multiply them by 10.76 in order to get Lux.
>>>
>>> Also, you'll need to add a source description for the sun in order to get
>>> the solar contribution as the camera sensor can not capture the intensity
>>> of the sun for the HDR image. Essentially the HDR image allows you to get
>>> a close approximation of the global diffuse value. I use gendaylit (see
>>> below) to generate the sun and sky scene. You can get the altitude,
>>> azimuth, direct-normal-illuminance and diffuse-horizontal-illuminance from
>>> the CSV file (be sure to multiply the latter two values by 10.76 to
>>> translate them from footcandles to Lux for input into Gendaylit). Also be
>>> sure to adjust your 'rtrace' results by dividing by 10.76 to get
>>> footcandles if you want to compare to the global-horizontal-illuminacne
>>> readings in the CSV file.
>>>
>>> ########Sun and Sky scene -----> global.rad
>>> !gendaylit -ang 45.41 85.92 -w -O 0 -L 80463.28 19916.76 | xform -e -rz
>>> 0
>>> void colorpict skypict
>>> 11 red green blue 140621_1530.hdr fisheye.cal fish_u fish_v -rx 90 -rz 180
>>> 0
>>> 0
>>>
>>> skypict glow skyglow
>>> 0
>>> 0
>>> 4 1 1 1 1
>>>
>>> skyglow source sky
>>> 0
>>> 0
>>> 4 0 0 1 180
>>>
>>> skypict glow groundglow
>>> 0
>>> 0
>>> 4 1 1 1 0
>>>
>>> groundglow source ground
>>> 0
>>> 0
>>> 4 0 0 -1 180
>>> #########
>>> # 3. the cmd.sh file
>>> oconv ./global.rad > ./scene_empty.oct
>>>
>>> echo '0 0 0 0 0 1' | rtrace -I -h -w -ab 1 -oov ./scene_empty.oct >
>>> ./results_position_irradiance_RGB_wm2.txt
>>>
>>> cat ./results_position_irradiance_RGB_wm2.txt | rcalc -e
>>> '$1=179*(0.265*$4+0.670*$5+0.065*$6)/10.76' > ./results_illuminance_lux.txt
>>> ##########
>>>
>>> When I run the above I get a global horizontal illuminance value from
>>> 'rtrace' of approx. 6900 footcandles. The photometer gave a reading of
>>> 7176 footcandles.
>>>
>>>
>>> I'm still working my brain around all this as well and hope that these
>>> discussions will foster a better understanding of how to use the HDR images
>>> for the highest level of accuracy possible.
>>>
>>> Hope this helps.
>>>
>>> Best,
>>> Chris
>>>
>>>
>>>
>>>
>>> On Jun 28, 2014, at 10:06 AM, Joe Smith <the.oat.cracker at gmail.com>
>>> wrote:
>>>
>>> Hi, I found 2 references and did a test to generate HDR image-based
>>> rendering, steps are explained below.
>>>
>>> But I'm still rubbing my head to understand how the Cartesian coordinates
>>> or the postion vector of a point on the sky is transformed as UV
>>> coordinates of the fisheye image as shown in the "angmap.cal" file. So,
>>> advices are greatly appreciated!
>>>
>>> Thanks!
>>> Joe
>>>
>>>
>>> References:
>>> 1. Debevec, P. (2002). Image-based lighting. IEEE Computer Graphics and
>>> Applications, 22(2), 26-34. doi: 10.1109/38.988744
>>> 2. Au, P. Y. P. (2013). HDR Luminance Measurement: Comparing real and
>>> simulated data. (Master of Building Science Thesis), Victoria University of
>>> Wellington.
>>>
>>>
>>> Steps:
>>> Step1. prepare the following 6 files and put them in the same folder
>>>
>>> #### 1.1 geom.rad ################################################
>>> red_plastic sphere ball
>>> 0
>>> 0
>>> 4 2 2 0.5 0.5
>>>
>>> steel sphere ball1
>>> 0
>>> 0
>>> 4 2 -2 0.5 0.5
>>>
>>> gold sphere ball2
>>> 0
>>> 0
>>> 4 -2 -2 0.5 0.5
>>>
>>> white_matte sphere ball3
>>> 0
>>> 0
>>> 4 -2 2 0.5 0.5
>>>
>>> crystal sphere ball4
>>> 0
>>> 0
>>> 4 0 0 1 1
>>>
>>> !genbox gray_plastic pedestal_top 8 8 0.5 | xform -t -4 -4 -0.5
>>>
>>>
>>> #### 1.2 materials.mat ################################################
>>> void plastic red_plastic
>>> 0
>>> 0
>>> 5 .7 .1 .1 .06 .1
>>>
>>> void metal steel
>>> 0
>>> 0
>>> 5 0.6 0.62 0.68 1 0
>>>
>>> void metal gold
>>> 0
>>> 0
>>> 5 0.75 0.55 0.25 0.85 0.2
>>>
>>> void plastic white_matte
>>> 0
>>> 0
>>> 5 .8 .8 .8 0 0
>>>
>>> void dielectric crystal
>>> 0
>>> 0
>>> 5 .5 .5 .5 1.5 0
>>>
>>> void plastic black_matte
>>> 0
>>> 0
>>> 5 .02 .02 .02 .00 .00
>>>
>>> void plastic gray_plastic
>>> 0
>>> 0
>>> 5 0.25 0.25 0.25 0.06 0.0
>>>
>>>
>>>
>>> #### 1.3 sky_and_ground.rad
>>> ################################################
>>> void colorpict hdr_image
>>> 7 red green blue 140621_1530.hdr angmap.cal u v
>>> 0
>>> 0
>>>
>>> hdr_image glow sky_glow
>>> 0
>>> 0
>>> 4 1 1 1 0
>>>
>>> sky_glow source HDR_sky
>>> 0
>>> 0
>>> 4 0 0 1 180
>>>
>>> # ground
>>> void glow ground_glow
>>> 0
>>> 0
>>> 4 1 1 1 0
>>>
>>> ground_glow source ground
>>> 0
>>> 0
>>> 4 0 0 -1 180
>>>
>>>
>>> #### 1.4 angmap.cal ################################################
>>> {
>>> angmap.cal
>>>
>>> Convert from directions in the world (Dx, Dy, Dz) into (u,v)
>>> coordinates on the light probe image
>>>
>>> +z is up (toward top of sphere, i.e. the zenith)
>>> +y is North
>>> }
>>>
>>> d = sqrt(Dx*Dx + Dy*Dy);
>>>
>>> r = acos(Dz)/PI;
>>>
>>> u = 0.5 - Dx/d * r;
>>> v = 0.5 + Dy/d * r;
>>>
>>>
>>> #### 1.5 view.vf ################################################
>>> # looking towards east
>>> #rvu -vtv -vp -12 0 0.5 -vd 1 0 0 -vu 0 0 1 -vh 60 -vv 40
>>> # looking towards west
>>> #rvu -vtv -vp 12 0 0.5 -vd -1 0 0 -vu 0 0 1 -vh 60 -vv 40
>>> # looking towards north
>>> rvu -vtv -vp 0 -12 0.5 -vd 0 1 0 -vu 0 0 1 -vh 60 -vv 40
>>> # looking towards south
>>> #rvu -vtv -vp 0 12 0.5 -vd 0 -1 0 -vu 0 0 1 -vh 60 -vv 40
>>>
>>>
>>> #### 1.6 cmd.sh ################################################
>>> oconv ./materials.mat ./sky_and_ground.rad ./geom.rad > ./scene.oct
>>>
>>> rvu -vf ./view.vf ./scene.oct
>>>
>>> #ximage ./sky.hdr
>>>
>>> rpict -x 2400 -y 2400 -t 30 -ab 1 -ar 50000 -aa 0.08 -ad 128 -as 64 -st 0
>>> -lw 0 -lr 8 -vf ./view.vf ./scene.oct > ./image.hdr
>>>
>>> pfilt -1 -x /3 -y /3 -r 1 ./image.hdr > ./image_filtered.hdr
>>>
>>>
>>> Step2. put the 140621_1530.hdr file provided by LBNL (
>>> http://flexskycam.lbl.gov) in the same folder
>>>
>>> Step3. run the cmd.sh batch file to produce the rendering
>>>
>>>
>>>
>>>
>>> On Sat, Jun 28, 2014 at 7:28 AM, Andrew McNeil <amcneil at lbl.gov> wrote:
>>>
>>>> Hi All,
>>>>
>>>> I haven't done any testing myself, I wanted to make the data available
>>>> right away so that others could tinker too (and maybe make it easier for
>>>> me).
>>>>
>>>> Joe - You're correct that the HDR sky image essentially replaces the
>>>> skyfunc modifier, here's a thread where Kyle was doing the same thing:
>>>> http://www.radiance-online.org/pipermail/radiance-general/2012-October/008962.html
>>>>
>>>>
>>>> Rob - In a clear sky condition our HDR images won't capture the full
>>>> luminance of the sun. Mksource would be helpful to zero out the pixels, but
>>>> the source that it makes won't be useful without adjusting the radiance of
>>>> the source to match that of the sun.
>>>>
>>>> Best,
>>>> Andy
>>>>
>>>>
>>>>
>>>>
>>>> On Fri, Jun 27, 2014 at 2:58 PM, Rob Guglielmetti <
>>>> rob.guglielmetti at gmail.com> wrote:
>>>>
>>>>> Hi German, and everyone else. Certainly one could use these HDR images
>>>>> to generate sky vectors and apply them to daylight coefficients for a given
>>>>> model(s). Greg Ward has created a cool tool called mksource to facilitate
>>>>> this process in Radiance, identifying small, intense pixels in the image;
>>>>> creating and placing Radiance light sources in their stead, and zeroing the
>>>>> pixels to avoid double counting.
>>>>>
>>>>> Considerations:
>>>>> - Capturing the true (full) dynamic range of an exterior scene with
>>>>> direct sun is difficult.
>>>>> - Using locally-captured HDR images for daylight availability analysis
>>>>> is statistically dubious. Granted, so is using TMY data, for different
>>>>> reasons. This is why I changed the title of this list to "considerations",
>>>>> from "problems". =)
>>>>>
>>>>>
>>>>>
>>>>>
>>>>>
>>>>> On Fri, Jun 27, 2014 at 3:38 PM, CHI-German Molina <gmolina at hdlao.com>
>>>>> wrote:
>>>>>
>>>>>> Wow, I have been thinking on doing this for a while... although I have
>>>>>> no idea where to start from.
>>>>>>
>>>>>> Is it possible to calculate the Daylight Coefficients of the building;
>>>>>> and use the HDR image to generate sky vectors and calculate different
>>>>>> options for optimizing daylighting?
>>>>>>
>>>>>> I am picturing a computer that, every 5 minutes, calculate the sky
>>>>>> vector, computes the interior lighting conditions, and simulates the
>>>>>> different lighting options performing a whole-building lighting control
>>>>>> with no photo sensors. Even more, maybe a whole neighborhood could use the
>>>>>> same camera. Nonsense?
>>>>>>
>>>>>> Thanks for sharing!
>>>>>>
>>>>>>
>>>>>> 2014-06-27 0:59 GMT-04:00 Joe Smith <the.oat.cracker at gmail.com>:
>>>>>>
>>>>>>> Hi, Andy, thanks for sharing LBNL's sky mapping experiment!
>>>>>>>
>>>>>>> Can you kindly advice on resources that elaborate on how to use HDR
>>>>>>> sky image for daylight simulation? Does it involve specifying the HDR
>>>>>>> image, rather than a "skyfunc", as the material identifier for the sky
>>>>>>> geometry? How is the pixel value of a given point on the HDR image
>>>>>>> converted to luminance value of the corresponding position on the sky?
>>>>>>>
>>>>>>> Thanks!
>>>>>>> - Joe
>>>>>>>
>>>>>>> Andrew McNeil <amcneil at lbl.gov>?2014?6?27???????
>>>>>>>
>>>>>>> Hi Everyone,
>>>>>>>>
>>>>>>>> LBNL has installed an HDR sky camera at our new FLEXLAB site:
>>>>>>>> http://flexskycam.lbl.gov. I've uploaded sample data, including hdr
>>>>>>>> images and csv datafiles, recorded by the camera for three days over the
>>>>>>>> past week( clear, partly cloudy and overcast). We're happy to share more
>>>>>>>> data with other researchers and daylight practitioners (but we don't have
>>>>>>>> much to offer yet).
>>>>>>>>
>>>>>>>> The images can be mapped to a Radiance sky for simulation under real
>>>>>>>> sky conditions. I have not used the sky HDR images yet, myself, so if
>>>>>>>> anybody uses them successfully please report back and share what you've
>>>>>>>> done!
>>>>>>>>
>>>>>>>> Questions about the camera hardware and capabilities should be
>>>>>>>> directed to Chris Humann at Terrestrial Light.
>>>>>>>>
>>>>>>>> Best,
>>>>>>>> Andy
>>>>>>>>
>>>>>>>
>>>>>>> _______________________________________________
>>>>>>> Radiance-general mailing list
>>>>>>> Radiance-general at radiance-online.org
>>>>>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>>>>>
>>>>>>>
>>>>>>
>>>>>>
>>>>>> --
>>>>>> *Germ?n Molina L.*
>>>>>> Ingeniero Trainee
>>>>>> Hunter Douglas Chile S.A.
>>>>>> Celular +569 89224445
>>>>>>
>>>>>> *Nota de Confidencialidad:* Este mensaje inclu?do los archivos
>>>>>> adjuntos son confidenciales y pueden contener informacion privilegiada
>>>>>> protegida por ley. Si Ud. no es el destinatario, deberia abstenerse de
>>>>>> copiarlo, distribuirlo, divulgarlo o usar la informacion contenida. Por
>>>>>> favor, avise inmediatamente al emisor y borre este mensaje de su sistema.
>>>>>> Los mensajes electronicos son susceptibles de ser cambiados, infectados o
>>>>>> adulterados sin autorizacion. No asumimos responsabilidad alguna por
>>>>>> ninguna clase de cambios o sus consecuencias. Usted debe estar informado
>>>>>> que la compania puede hacer un seguimiento de sus mensajes electronicos y
>>>>>> su contenido, gracias.
>>>>>>
>>>>>> *Confidentiality Notice:* The information contained in this email
>>>>>> message, including any attachment, is confidential and is intended only for
>>>>>> the person or entity to which it is addressed. If you are neither the
>>>>>> intended recipient nor the employee or agent responsible for delivering
>>>>>> this message to the intended recipient, you are hereby notified that you
>>>>>> may not review, retransmit, convert to hard copy, copy, use or distribute
>>>>>> this email message or any attachments to it. If you have received this
>>>>>> email in error, please contact the sender immediately and delete this
>>>>>> message from any computer or other data bank, Thank you.
>>>>>>
>>>>>> A informa??o transmitida ? confidencial e para conhecimento exclusivo
>>>>>> do destinat?rio. Sua utiliza??o, n?o autorizada, constitui crime pass?vel
>>>>>> de pris?o. Todas as precau??es poss?veis foram tomadas para garantir que
>>>>>> este e-mail n?o contenha v?rus. Uma vez que nossa empresa n?o pode assumir
>>>>>> responsabilidade por nenhuma perda ou dano causado por este e-mail ou de
>>>>>> seus anexos, recomendamos que o destinat?rio utilize seus procedimentos de
>>>>>> antiv?rus antes de qualquer uso.
>>>>>>
>>>>>> _______________________________________________
>>>>>> Radiance-general mailing list
>>>>>> Radiance-general at radiance-online.org
>>>>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> Radiance-general mailing list
>>>>> Radiance-general at radiance-online.org
>>>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>>>
>>>>>
>>>>
>>>> _______________________________________________
>>>> Radiance-general mailing list
>>>> Radiance-general at radiance-online.org
>>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>>
>>>>
>>> _______________________________________________
>>> Radiance-general mailing list
>>> Radiance-general at radiance-online.org
>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>
>>>
>>>
>>> _______________________________________________
>>> Radiance-general mailing list
>>> Radiance-general at radiance-online.org
>>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>>
>>>
>> _______________________________________________
>> Radiance-general mailing list
>> Radiance-general at radiance-online.org
>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>
>>
>>
>> _______________________________________________
>> Radiance-general mailing list
>> Radiance-general at radiance-online.org
>> http://www.radiance-online.org/mailman/listinfo/radiance-general
>>
>>
> -------------- next part --------------
> An HTML attachment was scrubbed...
> URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20140701/500d5529/attachment.html>
>
> ------------------------------
>
> _______________________________________________
> Radiance-general mailing list
> Radiance-general at radiance-online.org
> http://www.radiance-online.org/mailman/listinfo/radiance-general
>
>
> End of Radiance-general Digest, Vol 125, Issue 3
> ************************************************
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20140702/d6259732/attachment-0001.html>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: Archivo adjunto al mensaje.jpeg
Type: image/jpeg
Size: 5939 bytes
Desc: not available
URL: <http://www.radiance-online.org/pipermail/radiance-general/attachments/20140702/d6259732/attachment-0001.jpeg>
More information about the Radiance-general
mailing list