====? 文章 引自 Octane Help? ====

====? 翻譯 Google translate? ? ====

PATH TRACING

Now be ready to hunt for photons in the endless sea of ??Pathracing. Pathtracing is an advanced "unbiased" render method written for this purpose. With this method, you can obtain photorealistic images with physical certainty. Pathtracing may cause problems in some small light sources or you may not get full efficiency in the case of caustic reflections. In such cases you can use PMC Kernel (see PMC section).

現(xiàn)在準備好在無盡的Pathracing海中尋找光子。 Pathtracing是為此目的而編寫的高級“無偏”渲染方法。 使用此方法，您可以獲得具有物理確定性的逼真圖像。 路徑追蹤可能會在某些 small Light sources 小型光源中引起問題，或者在caustic reflections腐蝕性反射的情況下可能無法獲得完全的效率。 在這種情況下，您可以使用PMC內(nèi)核（請參閱PMC部分）。

Unfortunately, every good thing has a drawback: this method increases render times. This is the price we will always pay when we try to infiltrate the reality through the computer.

不幸的是，每件好事都有一個缺點：這種方法會增加渲染時間。 當我們試圖通過計算機滲透現(xiàn)實時，這是我們將永遠要付出的代價。

As we have already mentioned, when using the common options of the kernels, there may be only kernel-specific options that you have chosen, or some of the previous ones may not be visible. When you choose Pathtracing, two new features "Caustic blur" and "GI Clamp" are activated. Below we will explain only these options. We have already explained all the other options in this section in Directlighting. You can look at those sections as needed.

正如我們已經(jīng)提到的，當使用內(nèi)核的公共選項時，可能只有您選擇的特定于內(nèi)核的選項，或者某些先前的選項可能不可見。 當您選擇Pathtracing時，會激活兩個新功能“Caustic blur”和“GI Clamp”。 下面我們將僅解釋這些選項。 我們已在Directlighting中解釋了本節(jié)中的所有其他選項。 您可以根據(jù)需要查看這些部分。

Max. Samples 最大采樣 :??

Sets the maximum number of samples per pixel before the rendering process stops. The higher the number of samples per pixel, the cleaner the render. There is no rule as to how many samples per pixel are required for a good render, it is subjective and may vary depending on the content and complexity of the scene being rendered. For example, since Directlighting is a fast kernel, 500-1000 samples for static images and animations will suffice. If you have more than one direct and indirect light source in your scene and you are also using mesh light, you can increase a few hundred samples. But we can not say the same thing for Pathtracing kernel mode, for instance. As we've just mentioned, there is no magic number for it.

設置渲染過程停止前每個像素的最大采樣數(shù)。 每個像素的采樣數(shù)越多，渲染越清晰。 沒有關于良好渲染需要每像素多少采樣的規(guī)則，它是主觀的并且可以根據(jù)正被渲染的場景的內(nèi)容和復雜性而變化。 例如，由于Directlighting是一個快速內(nèi)核，靜態(tài)圖像和動畫的500-1000個采樣就足夠了。 如果場景中有多個直接和間接光源，并且您還使用mesh light，則可以增加幾百個采樣。 但是，對于Pathtracing內(nèi)核模式，我們不能這樣說。 正如我們剛剛提到的，它沒有固定的數(shù)字。

Diffuse Depth 漫射深度: ?

Gives the maximum number of diffuse reflections if GI Mode is set to Diffuse. 3-5 is enough for the most scenarios.

如果GI模式設置為“GI_DIFFUSE”，則給出最大漫反射數(shù)。 對于大多數(shù)場景來說，3-5就足夠了。

Specular Depth : ?

Controls how many times a ray is refracted after hit the surface without losing its energy. A zero number means that the ray does not hit the surface and can not continue on the path (reflect or refract). if it is greater than zero, it continues on its way through the surface and refracts until it loses its energy. Higher numbers mean higher render times but more color bleeding and more details in transparent materials. Low numbers can introduce artifacts or turn some refractions into pure black. You can see different specular depth results from the picture below.

控制光線在擊中表面后折射次數(shù)。零數(shù)字表示光線不會撞擊表面，無法在路徑上繼續(xù)（反射或折射）。如果它大于零，它繼續(xù)穿過表面并折射，直到它失去能量。 數(shù)字越大意味著渲染時間越長，但顏色滲透越多，透明材料的細節(jié)越多。 低數(shù)字可能會引入假象或?qū)⒁恍┱凵渥兂杉兒谏?您可以從下面的圖片中看到不同的鏡面深度結(jié)果。

Ray Epsilon? :?

The distance between the geometry and the light ray when calculating ray intersections for lighting and shadowing. Larger values push rays away from the geometry surface. Lower values are more accurate, but can cause artifacts on large or distant objects. Ray Epsilon is similar to Ray tracing bias in other rendering engines. Adjust Ray Epsilon to reduce artifacts in large scale scenes. Look at the picture below.

計算光線和陰影的光線交叉點時幾何體與光線之間的距離。 較大的值會將光線推離幾何表面。 較低的值更準確，但可能導致大型或遠距離物體上的偽影。 Ray Epsilon類似于其他渲染引擎中的（Ray tracing）光線跟蹤偏差。 調(diào)整Ray Epsilon以減少大型場景中的偽影。 看下面的圖片。

從左往右：1.再大場景中過小的 Ray epsilon 會產(chǎn)生光斑；2.在超小模型場景中過大的數(shù)值會倒錯誤；3.適合的數(shù)值

Filter Size?過濾器尺寸 : ?

Sets the filter size in terms of pixels. This can improve aliasing artifacts in the render. However, if the filter is set too high, the image can become blurry.

以像素為單位設置過濾器大小。 這可以改善渲染中的鋸齒偽像。 但是，如果濾鏡設置得太高，圖像可能會變得模糊。

CAUSTIC BLUR 焦散模糊 :

This feature is only active in Pathtracing and PMC Kernel. You can set the caustic reflections to look sharp or soft with this option. When you enter a low value, caustics will look sharp, but you can see the bright pixels called "fireflies" depending on the scene setup. When you enter high values, the caustics begin to appear blurry. This is one of the values you will definitely play in scene optimization.

此功能僅在Pathtracing和PMC內(nèi)核中有效。 您可以使用此選項將焦散反射設置為銳利或柔和。 當您輸入一個較低的值時，焦散會看起來很清晰，但您可以根據(jù)場景設置看到稱為“fireflies”的明亮像素。 輸入高值時，焦散開始變得模糊。 這是您在場景優(yōu)化中肯定會發(fā)揮的價值之一。

Info:?There are a few ways to reduce or eliminate Fireflies. In this Caustic matter, you can lower the GI Clamp value.

信息：有幾種方法可以減少或消除螢火蟲。 在此焦散物質(zhì)中，您可以降低GI Clamp值。

GI CLAMP :

It clamps the contribution for each path to the specified value. By reducing the "GI clamp" value, you can reduce the amount of fireflies caused by sparse but very strongly contributing paths, i.e. it reduces noise by removing energy. "Caustic blur", on the other hand, reduces noise by blurring caustics, but conserves energy. Keep this number between 1-3.

它將每條路徑的貢獻限制為指定值。 通過降低“GI clamp”值，可以減少由稀疏但非常強的貢獻路徑引起的fireflies數(shù)量，即通過去除能量來減少噪聲。 另一方面，“Caustic blur”通過模糊焦散來降低噪音，但節(jié)省能量。 將此數(shù)字保持在1-3之間。