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picogen 0.3 - volumetrics

By phresnel
Software: To learn more about picogen, the free software used to create this image, visit #picogen or [link] .

About the image, programming-wise: This week I implemented volumetric rendering in picogen, largely influenced by PBRT (actually, one could call the renderer to be of the "PBRT kind" :) ). After 3 days of spare time hacking (yay, that is not even a normal working day:D) I got this result.

About the image, image-wise: This is not a lens flare effect. Lense flare effects occur due to very bright light bouncing inside your camera's lens construction ([link]). What you see in this image are so called "crepuscular rays", sometimes called "god rays".

Shadow is the absence of light, so the dark regions are really volumetric shadows thrown by the mountains, into the dense atmosphere. Those light shafts are actually (near-) parallel (*), and it is the position of the observer and the wide distance of view that make them look like emerging from a common center. I still think this is a fascinating effect, even, or better, especially, after "implementing" them. More about that phenomenom: [link] .

(*) While god rays are indeed only near-parallel in nature (but that "near" is not obvservable by us), they are really parallel in picogen, as they are implemented in terms of a directional light source, which is programmerish for an optimized light that has no position, which is a very good approximation for sun light

There is also a version where I applied simple post-fx, which imho largely increase the image's quality: [link] .

oh, and finally, that is, after 3 years on dA, I realize you can type HTML here :/
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lyc's avatar
hmm i definitely prefer this to the sharpened version ;)

the shafts of light are really cool, great job!
phresnel's avatar
Thanks mate. Though I am just the code monkey in this case (okay, there are some specifics to picogen, but practically it's the same as in PBRT) :)

My gf was actually of the same opinion, so I think I postpone my post-fx plans :D

I have 2 more images coming up, but I was too lazy; also need to make moooar images. Btw, picogen-core (that is, the renderer) is now frozen feature-wise (except for a simple job file format), so all my next effort go into the GUI and finally, after a year has passed, into the release of 0.3 :)