V-Ray DMC采样器原理释疑

各采样器比较

自适应细分是一个几乎所有其他“有偏差的非物理渲染器”（注1）都在采用的算法。它是一种相对来说有点老式，但在绝大多数情形下都非常好用的算法。它会算出干净且采样细致的图像结果，在静帧渲染时的表现非常出色，但是与DMC采样器相比，自适应细分往往会在一些本可以采样再少一点的地方过多采样
DMC采样器，那么要在某些同样的地方求出同样质量的反射模糊可能就不用这么多样本，DMC是目前在求取镜头景深和三维运动模糊时最好用（时间短质量高）的光线追踪采样算法

详解“采样”，自适应采样

计算机自己判断出在有必要的时候，才增加对个别像素的采样。这就是自适应采样技术，因为采样的数目是依据图像的复杂程度而适应性变化的。那么在颜色对比比较明显的地方采样数量会增加
自适应细分和DMC采样的共同点是它们都是自适应性的采样算法，但是工作机制不同

细分采样器

细分算法的采样点是处于如图所示的像素顶角上，初始样本采集到信息以后，细分采样器会分析这些信息，然后来决定哪些像素需要更多的采样样本。每一个像素边角上的样本都被拿来比较，如果某个像素的色差大于参数面板中设定的颜色阈值（下图所示），Vray就会进一步细分这个像素，并且在这个像素上采集更多的样本
难以理解，先放着

Interview at the All Things Digital D5 Conference, Steve and Bill Gates spoke with journalists Kara Swisher and Walt Mossberg onstage in May 2007.

Kara Swisher: The first question I was interested in asking is what you think each has contributed to the computer and technology industry— starting with you, Steve, for Bill, and vice versa. Steve Jobs: Well, Bill built the first software company in the industry. And I think he built the first software company before anybody really in our industry knew what a software company was, except for these guys. And that was huge. That was really huge. And the business model that they ended up pursuing turned out to be the one that worked really well for the industry. I think the biggest thing was, Bill was really focused on software before almost anybody else had a clue that it was really the software that— KS: Was important? SJ: That’s what I see. I mean, a lot of other things you could say, but that’s the high-order bit. And I think building a company’s really hard, and it requires your greatest persuasive abilities to hire the best ...

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Commencement Address at Stanford University--“Stay hungry. Stay foolish.”

I am honored to be with you today for your commencement from one of the finest universities in the world. Truth be told— I never graduated from college. This is the closest I’ve ever gotten to a college graduation. Today I want to tell you three stories from my life. That’s it. No big deal. Just three stories. The first story is about connecting the dots. I dropped out of Reed College after the first six months but then stayed around as a drop-in for another eighteen months or so before I really quit. So why did I drop out? It started before I was born. My biological mother was a young, unwed graduate student, and she decided to put me up for adoption. She felt very strongly that I should be adopted by college graduates, so everything was all set for me to be adopted at birth by a lawyer and his wife. Except that when I popped out they decided at the last minute that they really wanted a girl. So my parents, who were on a waiting...

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产品随想 | 周刊第43期：历史上的今天

Products Huberman Lab https://hubermanlab.com/ 一款聚焦于健康的播客今日热榜 https://tophub.today/ 聚合展示，国内各热门榜单，对跟进热点非常有帮助，热点运营的好帮手 SketchyBar https://github.com/FelixKratz/SketchyBar A highly customizable macOS status bar replacement Mac菜单栏定制自定义程度很高，看作者展示的案例，暂时没想出这样的好处（不过应用本身的编辑，确实也没啥意义）生命在于折腾吧！ Thanks-Mirror https://github.com/eryajf/Thanks-Mirror 整理记录各个包管理器，系统镜像，以及常用软件的好用镜像，Thanks Mirror。 Musicn https://github.com/zonemeen/musicn 一个下载高品质音乐的命令行工具，音乐来源: 咪咕 Planet Minecraft A creative Minecraft community fansite sharing maps, minecraft skins, resource packs, servers, mods, and more. 里面有很多动人的故事可能是世界上最大的Minecraft社区，从2010年至今 The Uncensored Library https://www.uncensoredlibrary.com/en blockworks https://www.blockworks.uk/ "Distinctive maps for Minecraft that have educated players and risen to the level of art" 游戏也可以让人有更高的实现，而不仅仅是沉迷其中，国外游戏厂商比我们做的好太多 Minecraft_Memory_Bypass_GUI https://github.com/xingchuanzhen/Minecraft_Memory_Bypass_GUI 绕过Minecraft...

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巴菲特致股东信-1976年

笔记：为什么选择轻资产行业：当竞争疯狂时，不会强迫加入降价大战最终选择了费雪的思想，选择能理解的优秀企业，以合理的价格买入并长期拥有翻译：雪球：https://xueqiu.com/6217262310/131440258 备份：https://archive.ph/XLK0S 原文： To the Stockholders of Berkshire Hathaway Inc, After two dismal years, operating results in 1976 improved significantly. Last year we said the degree of progress in insurance underwriting would determine whether our gain in earnings would be "moderate" or "major." As it turned out, earnings exceeded even the high end of our expectations. In large part, this was due to the outstanding efforts of Phil Liesche's managerial group at National Indemnity Company. In dollar terms, operating earnings came to $16,073,000, or $16.47 per share. While this is a record figure, we consider return on shareholders' equity to be a much more significant yardstick of economic performance. Here our result was 17.3%, moderately above our long-term average and even further above the average o...

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巴菲特致股东信-1973年

笔记：在上一年度预测的今年竞争加剧导致利润下滑，真的发生了翻译Link：雪球：https://xueqiu.com/6217262310/131257618 备份：https://archive.ph/KIfdT 原文： To the Stockholders of Berkshire Hathaway Inc.: Our financial results for 1973 were satisfactory, with operating earnings of $11,930,592, producing a return of 17.4% on beginning stockholders' equity. Although operating earnings improved from $11.43 to $12.18 per share, earnings on equity decreased from the 19.8% of 1972. This decline occurred because the gain in earnings was not commensurate with the increase in shareholders' investment. We had forecast in last year's report that such a decline was likely. Unfortunately, our forecast proved to be correct. Our textile, banking, and most insurance operations had good years, but certain segments of the insurance business turned in poor results. Overall, our insurance business continues to be a most attractive area in which to employ capital. Management'...

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巴菲特致股东信-1975年

笔记：华盛顿邮报已成为伯克希尔第一重仓股翻译：雪球：https://xueqiu.com/6217262310/131409324 备份：https://archive.ph/4hgK3 原文： To the Stockholders of Berkshire Hathaway Inc.: Last year, when discussing the prospects for 1975, we stated “the outlook for 1975 is not encouraging.” This forecast proved to be distressingly accurate. Our operating earnings for 1975 were $6,713,592, or $6.85 per share, producing a return on beginning shareholders ’ equity of 7.6%. This is the lowest return on equity experienced since 1967. Furthermore, as explained later in this letter, a large segment of these earnings resulted from Federal income tax refunds which will not be available to assist performance in 1976. On balance, however, current trends indicate a somewhat brighter 1976. Operations and prospects will be discussed in greater detail below, under specific industry titles. Our expectation is that significantly better results in textiles, earnings added from recent acquisitio...

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Steve Jobs introduced the iPhone on January 9, 2007.

This is a day I’ve been looking forward to for two and a half years. Link Every once in a while, a revolutionary product comes along that changes everything. And Apple has been— well, first of all, one’s very fortunate if you get to work on just one of these in your career. Apple’s been very fortunate. It’s been able to introduce a few of these into the world. In 1984, we introduced the Macintosh. It didn’t just change Apple, it changed the whole computer industry. In 2001, we introduced the first iPod, and it didn’t just change the way we all listen to music, it changed the entire music industry. Well, today, we’re introducing three revolutionary products of this class. The first one is a widescreen iPod with touch controls. The second is a revolutionary mobile phone. And the third is a breakthrough internet communications device. So, three things: a widescreen iPod with touch controls; a revolutionary mobile phone; and a breakthrough internet communicat...

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产品随想 | 周刊第90期：史家之绝唱，无韵之离骚

Why AI Will Save the World https://a16z.com/2023/06/06/ai-will-save-the-world/ Marc Andreessen的雄文，十分有說服力，邏輯清晰辯證了現今AI監管拋出的5個可能的AI問題讀的過程中，腦海裏浮現的都是編程隨想那篇文章为什么马克思是错的？——全面批判马列主义的知名著作导读 https://program-think.blogspot.com/2018/09/Book-Review-The-Errors-of-Marxism-Leninism.html 兩者的思維鏈條、敘事方式，非常相似人民聖殿教 https://zh.wikipedia.org/zh-hk/人民圣殿教?useskin=vector 瓊斯自稱是神的化身，幾千年前轉世為釋迦牟尼，創建了佛教；後來又轉世為耶穌基督，創建了基督教；之後短期化身轉世為巴孛，建立巴哈伊信仰；最後轉世為列寧，將社會主義發揚光大。邪教徒聲稱自己轉世成了列寧，這說明了什麼？ Apple Vision https://stratechery.com/2023/apple-vision Omnivore https://github.com/omnivore-app/omnivore Omnivore is a complete, open source read-it-later solution for people who like reading. How the YouTube Algorithm Works in 2023: The Complete Guide https://blog.hootsuite.com/how-the-youtube-algorithm-works/#A_brief_history_of_the_YouTube_algorithm 外人眼中的YouTube推薦算法變遷 Histography https://histography.io/ “Histography" is interactive timeline that spans across 14 billion years of history, f...

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巴菲特致股东信-1974年

笔记：价格战企业的逻辑：需要降价获取销量--->需要降低成本--->怎么降？扩大规模以摊低成本--->提高固定资产投入--->净资产回报率会降低翻译：雪球：https://xueqiu.com/6217262310/131257947 备份：https://archive.ph/5CEP6 原文： To the Stockholders of Berkshire Hathaway Inc.: Operating results for 1974 overall were unsatisfactory due to the poor performance of our insurance business. In last year's annual report some decline in profitability was predicted but the extent of this decline, which accelerated during the year, was a surprise. Operating earnings for 1974 were $8,383,576, or $8.56 per share, for a return on beginning shareholders' equity of 10.3%. This is the lowest return on equity realized since 1970. Our textile division and our bank both performed very well, turning in improved results against the already good figures of 1973. However, insurance underwriting, which has been mentioned in the last several annual reports as running at levels of unsustainable profitability, turned dramatically worse...

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Interview with Steve Jobs, WGBH, 1990

Interviewer: what is it about this machine? Why is this machine so interesting? Why has it been so influential? Jobs: Ah ahm, I'll give you my point of view on it. I remember reading a magazine article a long time ago ah when I was ah twelve years ago maybe, in I think it was Scientific American . I'm not sure. And the article ahm proposed to measure the efficiency of locomotion for ah lots of species on planet earth to see which species was the most efficient at getting from point A to point B. Ah and they measured the kilocalories that each one expended. So ah they ranked them all and I remember that ahm...ah the Condor, Condor was the most efficient at [CLEARS THROAT] getting from point A to point B. And humankind, the crown of creation came in with a rather unimpressive showing about a third of the way down...

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