pnn32's avatar

Room as camera obscura using Octane Render

By pnn32
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30 Comments
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This is mostly 'proof-of-concept' / 'technology demo' image, rather than completed artwork :) But it can be interesting for someone because of:
 Bullet; Green  Demonstration of possibilities of unbiased render engine - the small hole in wall works exactly as it should IRL, projecting environment light to room's interior, while turning it upside down.
 Bullet; Green  Nice artistic effect of room turned into 'camera obscura', can be featured in various scenes
 Bullet; Green  It's the good challenge for other (unbiased) render engines.. let's hope it's also possible to render in iRay or some other ones

Unfortunately, the render process requires just incredible amount of computing power and the first appropriate image appears only after noticeable amount of time. So... to render full scene (with characters, for example) in appropriate time and low noise, you will need a rig with several GTX Titan at least :faint:

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Bullet; Blue More links on theme:

Artistic works
thecreativediary.blogspot.com/…

Detailed (real-world) tutorial with explanations and tips
content.photojojo.com/diy/diy-…

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Bullet; Purple Tech details:
Octane Render 2.24.2, 28k spp in PMC mode
Room was modeled in Blender (having size of 3x3x4.5 meters with 50mm round hole in one wall), OBJ file in attachment
Other props are from Poser (The photo camera with tripod >> www.renderosity.com/mod/freest… )
Environment HDRI from HDRLabs >> www.hdrlabs.com/
Published:
© 2016 - 2020 pnn32
Comments30
anonymous's avatar
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Laspe's avatar
Interesting experiment and impressive result!
Piitas's avatar
Weird and interesting :) (Smile)  I had no idea that could work.
It worked with LuxRender too: Camera Obscura with LuxRender
pnn32's avatar
Thank you for mentioning my work and congrats with such nice render challenge result :D
Just wondering, how much time it takes with LuxRender... (CPU-only? Or you have access to network rendering cluster? :))
Piitas's avatar
Of course. I would never have found out about the camera obscura thing if it wasn't for your render. So thank you! :) (Smile)
The LuxRender one was rendered with cpu in something like 12 hours and 5kspp. LuxRender can use portals to help guide the rendering process in cases like these, and they gave an insane speedup. Without portals it would be really slow.
pnn32's avatar
The Octane is also has special 'portal' material, but I don't see any improvements (in terms of speed or image quality) with it.. but probably it can help in such specific case...
P.S. Here is another render challenge >> fav.me/d9lfaag , the purpose is getting proper reflections from those small mirrors. The disco ball model is free to download and modify, if needed :)
ruhney71's avatar
JUST AWESOME!

I worked on a camera obscura ones. We placed a storage container in the town center, drilled a hole in the side, placed photo sensitive paper on the adjacent wall and let it sit there for hours. At the end of the day we took the paper out and developed it in our lab. Cool thing was that insite of hundreds of people crossing the town center, no soul was seen on the image. Just the buildings. Movement is not registered.

Thanks for putting this up! Really cool!!!! 
pnn32's avatar
So you can easy imagine, how long should be exposure for appropriate image quality... especially when you use software emulation, not hardware (Sun-based, really) implementation  :D
firestorm31z's avatar
upside down images. 

so the images are projected on the walls upside down?

just trying to wrap my head around on why someone would want upside down images on a wall. :D
pnn32's avatar
No one wants that upside down turn.. so some artists use additional prism behind hole for projection correction :)
firestorm31z's avatar
projection correction?  please explain.  I'm clueless about that.
pnn32's avatar
I mean turning image again upside down.. so it will be finally projected correctly on wall.
Tako-Yakida's avatar
Great result! Unbiased rendering engines are definitely cool for this reason.
Chanteur-de-Vent's avatar
И сколько эта прелесть заняла в часах (днях)?
pnn32's avatar
На самом деле немного :)  меньше часа. Проблема в том, что первые минуты виден лишь черный квадрат с отдельными пикселями, и неясно, когда хоть что-нибудь 'проявится'. Да и заметного снижения шумов (ждал до 40k spp) не происходит в процессе рендеринга... возможно, что проявляются ограничения алгоритмов.
Много времени ушло на эксперименты, в частности понимание принципа, что чем меньше размер отверстия, тем лучше резкость изображения, но меньше светосила этого 'объектива'.. так что пришлось выбирать компромисс.
В описаниях реальных комнат говорилось, что глаза начинают видеть картинку через несколько минут... хотя глаз способен реагировать на отдельный фотоны.. вот так-то.
firestorm31z's avatar
well that certainly explains the "multi" Titan comment. :D

is this as GPU unit or as a CPU unit?
pnn32's avatar
Did you mean what is 'rig'?  Most commonly used as term for workstation/server with several GPUs or external box with these GPUs.
firestorm31z's avatar
well, I obviously wrote it poorly.

but yeah, the question is for a render farm rig setup.  a workstation with multiple GPUs (GPU unit) or multiple computers (CPU unit) with 1 GPU.
pnn32's avatar
Second option (computers ...with 1 GPU in each ?) is called distributed network rendering. The first can be more effective, but installing a lot of GPUs into one workstation can has technical limits or can be too expensive (special system boards, external GPU boxes and so on are very expensive).
firestorm31z's avatar
there is the other aspect in having multiple gpus in one machine, multiple monitors! :D
Chanteur-de-Vent's avatar
Ну, допустим что человеческий глаз различает только не менее 4-5 фотонов, и то только после нескольких дней в темной комнате вообще без света. Так что несколько минут адоптации - это фигня. 

Если хочешь, могу попробовать потестировать в Iray.
pnn32's avatar
Да, было бы интересно посмотреть, как с таким iRay справится. Модель комнаты во вложении, HDRI по ссылке в описании, из рекомендаций  - поставить значение imager exposure (не знаю, как точно в iRay это называется) и мощности окружающего света как можно больше, чтобы быстрее увидеть результаты.
Chanteur-de-Vent's avatar
Первые тесты с треском провалились. Поставила оба сеттинга на максимум, увеличила до максимума время и количество самплов, она закончила за 10 мин и выдала девственно чистый черный экран. 

Сегодня вечером попробую найти способ запустить "бесконечный" рендер, без ограничений.
pnn32's avatar
А размер объекта (комнаты) был правильно выставлен при добавлении в сцену?  Должны быть единицы измерения  - метры. Дальше если только увеличивать размер отверстия, но тогда снизится резкость.
Chanteur-de-Vent's avatar
Эммм... Черт, могла и напутать. Надо будет пересмотреть. Скорее всего загрузила в см, а потом увеличила до какого-то произвольного размера.
anonymous's avatar
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