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Appleseed – open-source physically-based rendering engine

appleseedhq.net

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Re: Appleseed – open-source physically-based rendering engine

#22

Here are some render comparisons for the curious: http://appleseedhq.net/stuff/renderers-comparison/index.html

How am I supposed to compare these three on the top as a non-expert in this area? The middle one looks noisier than the other two. I notice the one on the left has darker color in dresser which may be an advantage of correct, color handing but might be incorrect with one on right being brighter due to the correct handing of window's light on it. And what's up with the graininess of all of them? Just a few things that…

Without knowing the settings which were used by each renderer (and thus stuff like the BSDF materials, sampling techniques, random number generator sequences, etc, etc), it's very difficult to say.

All these things play a crucial part in how efficiently a renderer can produce an image with as little noise as possible.

But it's also possible to look through the noise (ignore it), and look for issues - i.e. the Classroom scene is very odd as Appleseed doesn't have soft shadows (what light type was used? PhysicalSky/Sun? HDR IBL?), and the Tungsten illumination from the environment is less warm.

Re: Appleseed – open-source physically-based rendering engine

#23
post #17

Earlier quoted context omitted.

How am I supposed to compare these three on the top as a non-expert in this area? The middle one looks noisier than the other two. I notice the one on the left has darker color in dresser which may be an advantage of correct, color handing but might be incorrect with one on right being brighter due to the correct handing of window's light on it. And what's up with the graininess of all of them? Just a few things that…

> And what's up with the graininess of all of them? I am not a rendering expert either but IIRC "physical rendering" works by shooting photons across the scene based on a random distribution, and in the end, the finished rendering is an average version of all photon passes. If you don't shoot enough photons, the averaged out version will be noisy because there will be some hotspots were significantly more photons hit…

Typically, it's not using photons but the other way round, paths are started from the camera primarily.

The noise stems from the simple fact that those renderers try to solve an infinte dimensional integral (all light reflected by all surfaces) with stochastic Monte Carlo methods, the most popular being path tracing. There are other methods (finite element radiosity for example) to simulate light transport that do not exhibit stochastic noise, but those have fallen out of favor.

Re: Appleseed – open-source physically-based rendering engine

#24

This looks really beautiful. The fact that it's open source adds to that beauty. I'm not even interested in physically based rendering and it makes me want to play with it.

If you want to learn about state of the art rendering, check out pbrt.org. Even without the book, the source code contains a wealth of information and was written for teaching.

Re: Appleseed – open-source physically-based rendering engine

#25

It's all cool and awesome, but why put all those resources into new renderer, when one could contribute to Blender and such, which are way more mature?

1. Because it's fun. 2. Because you're using a different program than blender. 3. Because you want to work on code that you know wouldn't get accepted in the blender code base anyway. 4. Because you can.

I have contributed patches to Blender that got accepted. Even I feel the urge to write my own render engine, to try out different approaches and just so I can claim "I wrote that".

Re: Appleseed – open-source physically-based rendering engine

#27

Earlier quoted context omitted.

Tensorflow is also managed by the most influential tech company in the world.

Right; Tensorflow is managed well, and working on it might lead to a job, while appleseed seems like yet another open-source time sink with few prospects. Obviously money isn't everything, so maybe there's a better criteria for judging projects, but at least on the "lasting impact on the world" front appleseed seems to fall short...

>Right; Tensorflow is managed well, and working on it might lead to a job

Tensorflow's management is not relevant to its popularity. It's been well demonstrated that companies are tripping all over themselves to use anything put out by Google and/or Facebook, regardless of its applicability to the company's actual problem space or the quality of the product as compared to competitors. There are a lot of people out there just itching to find any excuse to blow millions of dollars deploying any open-source project touted by Google or Facebook, often blissfully unaware that these projects are born out of necessity, not amusement, and that Google/FB would've happily been using a mature, out of the box solution if it accommodated their needs.

The point is saying "Look at an independent guy's project. It's not even as active as some of Google's projects, and they're just one of the biggest companies in the world! Hah!" is really, really unfair, and doesn't say anything about anything.

>Obviously money isn't everything, so maybe there's a better criteria for judging projects, but at least on the "lasting impact on the world" front appleseed seems to fall short...

That the project does not now appear poised for world domination doesn't mean it's not significant, influential, or important, or that it won't eventually go on to have a larger-than-expected impact. This is particularly true if it explores an interesting or rarely-used paradigm, or is otherwise noteworthy for its technical excellence.

KDE's Konqueror began as a custom web browser for their desktop environment and easily could've been classified "yet another open-source timesink". But its engine, KHTML, became the foundation for WebKit. If someone is interested in making something interesting, there's no reason to begrudge it.

Re: Appleseed – open-source physically-based rendering engine

#28

It's all cool and awesome, but why put all those resources into new renderer, when one could contribute to Blender and such, which are way more mature?

Two points: Blender is not a renderer, it's a modelling and animation program with a built-in renderer, Cycles. But it can connect to other renderers, too. Cycles is not that old. It replaced Blender's prior renderer just a few years ago.

Appleseed has also been under active development for 7+ years; so not that young, especially considering that physically-based renders really only started coming into full production use 3-4 years ago. There are still many visual effects studios using approximation-based setups today, so I'd say there's lots of room for "new renderers" to carve their niche.

Re: Appleseed – open-source physically-based rendering engine

#30

If you're into graphics pipelines, here's a few interesting videos of Gaffer node networks rendering with Appleseed: http://www.gafferhq.org/demos/

how does gaffer compare to BMD Fusion? Thanks!

BTW it would be really great if the webmaster of gafferhq.org considered to add some contrast to the parts of the website that should be read by visitors.

(aka http://contrastrebellion.com/ )

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