waking up.

醒來後。

They also served as the big reveal of a technical breakthrough.

它們也是一個技術突破的大揭祕。

Final Fantasy: The Spirits Within was one of the first movies with a realistic human

最終幻想：靈魂深處》是第一批具有現實人類的電影之一。

CGI character — at least in theory.

CGI角色--至少在理論上。

To our eyes today, the movement and textures make it look at best like a video game cutscene.

在我們今天的眼中，這些動作和紋理使它看起來最多隻是一個視頻遊戲的剪輯。

But focus on the skin.

但要把注意力放在皮膚上。

How did we go from lifeless skin to skin that, on Alita, a stylized character with giant

我們是如何從沒有生命力的皮膚變成在《阿麗塔》中具有巨大的風格化角色的皮膚的呢？

eyes and a robot body, looks so much better?

眼睛和機器人的身體，看起來好多了？

How do we make fake skin look real?

我們如何使假的皮膚看起來真實？

That journey to realistic skin includes pore mapping, the appearance of light on apples

通往真實皮膚的旅程包括毛孔映射、蘋果上的光線外觀

and chicken, and knowing the difference between a glass of whole and skim milk.

和雞肉，並知道一杯全脂和脫脂牛奶之間的區別。

I'm finding it really hard not to feel like a total stoner thinking about my skin —

我發現真的很難不覺得自己是一個完全的石頭人，想著我的皮膚----。

I'm touching my face right now.

我現在就在摸我的臉。

“Honestly, when we go through looking at this stuff, we're all doing this and like

"老實說，當我們通過看這些東西時，我們都在做這個，而且喜歡

trying to look in the mirror.

試圖照鏡子。

My name is Nick Epstein.

我的名字是尼克-愛潑斯坦。

I was a visual effects supervisor on Alita: Battle Angel.”

我是《阿麗塔：戰鬥天使》的視覺效果主管。"

Alita: Battle Angel is a 2019 action movie based on the manga and it features a stylized

阿麗塔：戰鬥天使》是一部基於漫畫的2019年動作電影，它的特點是風格化的

character that's perfectly believable.

角色，是完全可信的。

She's come a long way from this guy, the Scorpion King from the Mummy Returns.

她已經從這個傢伙，即《木乃伊歸來》中的蠍子王，走過了漫長的道路。

This shot is so infamous that the VFX YouTube channel Corridor Crew spent a whole video

這個鏡頭是如此臭名昭著，以至於VFX YouTube頻道Corridor Crew花了一整個視頻

trying to fix it.

試圖修復它。

There are a lot of problems, but a big one is the skin.

有很多問題，但其中一個大問題是皮膚。

The Mummy Returns' Scorpion King is played by the Rock.

木乃伊歸來》的蠍子王是由洛克扮演的。

You wouldn't know it.

你不會知道的。

But Alita definitely resembles the actor who played her.

但阿麗塔絕對與扮演她的演員很像。

“We needed to make sure that we were capturing Rosa's performance, like the heart of the

"我們需要確保我們捕捉到了羅莎的表現，就像心臟一樣。

movie was really Rosa's performance as Alita.

電影中，羅莎扮演的阿麗塔的表現真的很好。

So we actually built a fully digital version of Rosa.

是以，我們實際上建立了一個完全數字版的羅莎。

And then we could apply sort of our sort of more, I guess, normal realism factors and

然後，我們可以應用我們的那種更多的，我想，正常的現實主義因素和

barometers to that.”

"的晴雨表。

Getting that facial model right is a crucial first step for the skin's movement.

把握好這個面部模型是皮膚運動的關鍵第一步。

When the hard work begins.

當艱苦的工作開始時。

“I have four factors I think.

"我有四個因素，我想。

Albedo, displacements, subsurface, and then dynamic changes and deformations and so on.”

反照率、位移、次表層，然後是動態變化和變形等等。"

Albedo is the base color map for your character.

反照率是你的角色的基礎顏色圖。

Imagine the color of a face in a void.

想象一下，在虛空中的臉的顏色。

No features, no wrinkles, no lights shining on it.

沒有特徵，沒有皺紋，沒有燈光照耀。

See how I make the cheeks a little red, the forehead a little lighter.

看我如何使臉頰有點紅，額頭有點淺。

That base is crucial to realism, and it's incredibly dynamic.

這個基礎對現實主義至關重要，而且它具有難以置信的活力。

Based on Rosa Salazar's real skin, they adjusted Alita's albedo map for different moods,

根據羅莎-薩拉扎的真實皮膚，他們為不同的情緒調整了阿麗塔的反照率圖。

health, everything.

健康，一切。

“So we could then sort of compare the albedo map when she's like really angry, for example,

"是以，我們可以在她非常生氣的時候比較反照率圖，例如。

with a neutral pose, and then extract basically like a blood flow map from that.

以中立的姿勢，然後從中提取基本上像血流圖一樣的東西。

And the shader could then, when she gets angry in her performance, dial in that extra blood

然後，當她在表演中發怒時，著色器可以在她的表演中撥出那個額外的血。

flow.”

流"。

Displacement maps push the scan up or down.

位移圖將掃描向上或向下推進。

Imagine how this little guy is flat, but features or a wrinkle here might change the height of

想象一下，這個小傢伙是平的，但特徵或這裡的皺紋可能會改變高度。

his face.

他的臉。

Look at all the detail in the Scorpion King's face here versus Imhotep's face in the next

看看這裡的蠍子王的臉和下一張的伊姆霍特普的臉的所有細節。

shot.

鏡頭。

That's the detail you can see in the close ups in Alita.

這就是你在《阿利塔》中的特寫鏡頭中可以看到的細節。

It's way smaller than wrinkles.

它比皺紋小得多。

“We call it micro geometry, even pore level displacement that's what gives you your oiliness,

"我們稱之為微觀幾何學，甚至是毛孔水準的位移，這就是給你的油性。

the specular response in your skin, which you can see even just looking at me in the

在你的皮膚上的鏡面反應，你可以看到，即使只是看著我在

in the camera here, you know, my forehead is very different to my nose, very different

在這裡的相機裡，你知道，我的額頭和我的鼻子非常不同，非常不同。

to my cheeks, and to my chin.

到我的臉頰，到我的下巴。

Unfortunately, my forehead is quite shiny, my nose also shiny, but my cheeks less so

不幸的是，我的額頭相當光亮，我的鼻子也很光亮，但我的臉頰不那麼光亮。

and that they're fairly isotropic, without direction, I have a very clear flow direction

而且它們是相當各向同性的，沒有方向，我有一個非常明確的流動方向

that way, a flow direction this way.

這樣，一個流動方向是這樣的。

We have a sort of reverse flow direction around my chin.

我們在我的下巴周圍有一種反向的流動方向。

So we actually draw curves on along these flow lines.

所以我們實際上是沿著這些流線畫曲線。

Some extreme close ups, we you know, we knew that the camera was going to basically fly

一些極端的特寫鏡頭，我們知道，我們知道攝影機基本上是要飛的。

into Alita's eye.”

進入阿麗塔的眼睛。"

But the difference between this face and this one isn't just the skin.

但這張臉和這張臉的區別不僅僅是皮膚。

It's what happens beneath it.

這是發生在它下面的事情。

“My name is Henrik Wann Jensen, and I'm the chief scientist of Luxion, makers of Keyshot.

"我的名字是亨利克-萬-詹森，我是Luxion公司的首席科學家，Keyshot的製造商。

And I specialize in computer graphics, in answering the question why do things look

而我的專長是計算機圖形學，在回答為什麼事物看起來是

the way they do and how can you simulate it on a computer?

他們的方式，以及你如何在計算機上模擬它？

See when we wrote the first paper as you may have noticed, we did some measurements in

當我們寫第一篇論文時，你可能已經注意到了，我們做了一些測量，在

it.

它。

So we actually went to the local supermarket with a laser pointer.

所以我們真的帶著脈衝光筆去了當地的超市。

I was shining on on the on the milk, we were shining on the meat.

我在照耀著牛奶，我們在照耀著肉。

And actually the guys who ran the supermarket came to us and what are you doing?

而實際上，經營超市的人來到我們這裡，你在做什麼？

This is not good.”

這不是好事。"

The big idea of that breakthrough 2001 paper, work that got the team to the technical Oscars,

那篇突破性的2001年論文的大意，是讓團隊進入奧斯卡技術獎的工作。

was that the way they'd seen light bounce through food was true of almost everything.

他們看到光通過食物反彈的方式幾乎對所有東西都是如此。

And if it could be simulated more quickly, that would make all computer graphics look

而如果能更快地進行模擬，這將使所有的計算機圖形看起來

more real, including skin.

更加真實，包括皮膚。

See how the laser bounces off the spoon?

看到脈衝光是如何從勺子上反彈的嗎？

But when I put my hand in front of it, the light passes through, and even bounces around

但當我把我的手放在它前面時，光線就會通過，甚至會反彈。

underneath?

在下面？

This drawing breaks down as an illustration, because light passes through and bounces under

這幅畫作為一個插圖被打破了，因為光線會穿過並在下面反彈。

our skin.

我們的皮膚。

Computers could simulate subsurface scattering, like they do with this marble.

計算機可以模擬地表下的散射，就像他們對這塊大理石所做的那樣。

But they did it by simulating every single bouncing light photon.

但他們是通過模擬每一個反彈的光子來實現的。

That took way too long.

這花了太多時間。

So most of the time, computer animation couldn't bother with it.

是以，大多數時候，電腦動畫都不可能去理會它。

It makes the Rock look wrong — light is bouncing off him, not passing through the

這使岩石看起來不對勁--光線從他身上反彈，而不是穿過他。

skin.

皮膚。

It affected other shots, too.

這也影響了其他的拍攝。

“In Shrek, they actually have a cookie guy and some milk.

"在《史萊克》中，他們實際上有一個吃餅乾的人和一些牛奶。

And if you ever see that shot, it looks like white paint, which was exactly the example

如果你看到那個鏡頭，它看起來像白色的油漆，這正是例子

we said if you don't do this properly, it's actually going to look like white paint.”

我們說，如果你不好好做，它實際上會看起來像白漆。"

Jensen and his colleagues figured out how to simulate subsurface scattering more efficiently.

詹森和他的同事想出瞭如何更有效地模擬地下散射的方法。

That changed animation.

這改變了動畫。

“Then in Shrek 2, they now knew about this technology.

"然後在《史萊克2》中，他們現在知道了這項技術。

And then they went all in on the milk.

然後他們全身心地投入到牛奶中。

So they had a ton of milk.

所以他們有一噸的牛奶。

But they now did the full subsurface scattering.

但他們現在做的是全面的次表面散射。

And so it had a little bit of an impact on that as well.

是以，它對這一點也有一點影響。

it's funny because I went to talk to Sony and you never know what people are interested

這很有趣，因為我去和索尼談，你永遠不知道人們對什麼感興趣。

in.

在。

They say, oh, you're the milk guy.”

他們說，哦，你是賣牛奶的。"

Subsurface scattering could efficiently simulate the different ways light passed through whole

次表層散射可以有效地模擬光線通過整體的不同方式。

versus skim milk, and also skin, or at least the beginning of it.

與脫脂牛奶相比，還有皮膚，或至少是皮膚的開始。

“But when we created the initial subsurface scattering algorithm, you're set up based

"但是，當我們創建最初的次表面散射算法時，你的設置是基於

on this assumption that you hit the skin and then everything is the same underneath.

在這個假設上，你打到了皮膚，然後下面的一切都一樣。

And of course, real human skin is not like that.

當然，真正的人類皮膚也不是這樣的。

We have different layers like epidermis, dermis.

我們有不同的層次，如表皮、真皮。

And we looked at sort of the basic things that decide what humans can look like.

我們看了一些決定人類可以看起來像什麼的基本東西。

And it turns out melanin, you actually have different melanin types, we have one that's

而事實證明，黑色素，你實際上有不同的黑色素類型，我們有一個是

lighter melanin type, one that's more on the brown side, on the dark side, you have to

較淺的黑色素類型，一個更偏向於棕色的，偏向於深色的，你必須

have mixtures of those to get the correct skins.

有這些的混合物來獲得正確的皮膚。

You could actually do a very convincing, now, rendering of human skin.”

你實際上可以做一個非常有說服力的，現在，人類皮膚的渲染。"

“So, you know, I've talked about how we define regions for micro geometry, some of

"所以，你知道，我已經談到了我們如何為微觀幾何學定義區域，一些

the things we did also revolved around dynamic scans.

我們所做的事情也是圍繞著動態掃描進行的。

So we actually had footage of what scan data, so it's this 3d three dimensional data of

是以，我們實際上有什麼掃描數據的鏡頭，所以它是這個三維立體數據的

Rosa running through Harvard lines of sort of every expression we could we could ask

羅莎通過哈佛線的排序的每一個表達，我們可以我們可以問

her to do.”

她要做的。"

Harvard lines are a series of sentences that help hit all the phonemes—chunks of speech

哈佛線是一系列的句子，有助於打擊所有的音素--語音塊

in a conversation.

在一次談話中。

It's for audio, but it can help artists see every possible way somebody's mouth can move

它是用於音頻的，但它可以幫助藝術家們看到某人的嘴巴可以移動的每一種可能方式。

when they're talking.

當他們說話的時候。

I'm doing this video.

我在做這個視頻。

It includes these things called Harvard lines, and I was hoping you could read some of them.

它包括這些被稱為哈佛線的東西，我希望你能讀到其中一些。

[Reading overlapping Harvard lines]

[閱讀重疊的哈佛線]

Early reviews for Final Fantasy: The Spirits

最終幻想：精神》的早期評論

Within focused on it as a treat for the eyeballs.

內專注於它是對眼球的一種享受。

Since then, increasingly complex simulations of not just skin but light and movement have

從那時起，不僅是皮膚，還有光線和運動的越來越複雜的模擬。

made visual effects look even more real.

使得視覺效果看起來更加真實。

The only question is how much further is left to go.

唯一的問題是還能走多遠。

“Take the winding path to reach the lake, note closely the size of the gas tank.

"走蜿蜒的小路到達湖邊，仔細注意油箱的大小。

It snowed rained and hailed the same morning the meal was cooked before the bell rang.

當天早上下了雪，下了雨，下了冰雹，在鈴聲響起之前，飯菜就已經煮好了。

What joy there is in living.”

活著是多麼的快樂"。

“One of the immediate effects that that sort of the visual effects industry they jumped

"視覺效果行業的一個直接影響是，他們躍躍欲試。

on right away was if you also have someone who's lit from behind, you see light passing

如果你有一個人從後面被照亮，你就會看到光從後面穿過。

through the ear.

通過耳朵。

If you look at movies like like Harry Potter with Dobby, the character, they were the first

如果你看一下像《哈利-波特》這樣的電影，多比這個角色，他們是第一個

to really adopt this technology.

來真正採用這項技術。

They all had big ears so they were very excited about that, and you'll see a lot of glowing

他們都有大耳朵，所以他們對此非常興奮，你會看到很多發光的東西。

light coming through the ears.”

光線從耳朵裡透出來。"