使用ZBrush制作牛角怪的工作流程

從一個快速的ZBrush雕刻到一個完全實現(xiàn)的生產(chǎn)就緒的角色或生物可能是一個非常鈍和壓倒性的過程。 在此演練中，我將嘗試繪制此過程中所有階段的概述，以便更好地了解所涉及的步驟。

Taking a character or creature from a quick ZBrush sculpt to a fully realized, production ready asset can be a very obtuse and overwhelming process. During this walkthrough I will try to map out an overview of all the stages in this process, so you get a better understanding of the steps involved.

From sketch to sculpt

To get warmed up for other projects, I often do some quick ZBrush sketch sculpts from my imagination; this guy actually started off as one of these. Using my trusty handful of brushes, I went from two spheres; one for the head and one for the torso, to a semi-final sculpt using DynaMesh. I mostly use the Move and Clay Tubes brushes for overall mass, then DamStandard and Pinch with its modifier setting turned to 100 for detail carving. The hair tentacles were painted in using the Curve Tubes brush, with a little bit of tapering to the thickness along the curve length.

從草圖到雕刻

為了得到其他項目的熱身，我經(jīng)常做一些快速的ZBrush草圖雕塑; 這個家伙其實開始是其中之一。 用我信賴的少量筆刷，我從兩個角度去做; 一個事頭，一個是軀干，使用DynaMesh。 我主要使用移動和粘土管刷為總體質(zhì)量，然后DamStandard和Pinch，其修改器設(shè)置變?yōu)?/span>100進行細節(jié)雕刻。 使用曲線管刷將頭發(fā)觸角涂抹，沿著曲線長度略微縮小至厚度。

Retopology

I usually retopologize my meshes when the sculpt is about 90% done, this is because I know that the process of reprojecting the details onto the new geometry will usually introduce a few issues. I often will have to resculpt some of the more troublesome areas such as the corners of the mouth and eyelids. Depending on how much control I need over the edge flow, I'll use either ZRemesher (less control but much faster) or TopoGun (more control but takes way longer) for this.

Retopology

當?shù)袼艽蠹s完成90％時，通常會重新對我的網(wǎng)格進行重新定位，這是因為我知道將細節(jié)重新投影到新幾何體上的過程通常會引入一些問題。 我經(jīng)常會重塑一些比較麻煩的地方，比如嘴角和眼瞼的角落。 根據(jù)邊緣流程需要多少控制，我將使用ZRemesher（更少的控制但更快）或TopoGun（更多的控制，但是需要更長的時間）。

Laying out UVs

As soon as the retopologized mesh is in and the details are reprojected, it is time to unwrap some delicious UVs. If you're texturing in MARI, UV seams aren't really an issue. You should however plan ahead, so that your UV's are set up to make the texturing phase as efficient as possible. Adding a repeating pattern around the neckline of your character's tunic? Then unwrapping that section into a straight horizontal patch will make it a lot easier to paint than if it's some weird snake like spiral.

鋪設(shè)UVs

一旦重新開放的網(wǎng)狀物，細節(jié)被重新投射，現(xiàn)在是時候打開一些UVs。 如果您在MARI紋理，UV接縫并不是一個問題。 然而，您應(yīng)該提前計劃，以便您的UV被設(shè)置為使紋理化階段盡可能高效。 在你的角色長袍的領(lǐng)口附加一個重復(fù)的圖案？ 然后將該部分展開成一個直的水平補丁將使它更容易繪制，如果它是一些奇怪的蛇像螺旋。

Texture painting in MARI Indie

I use MARI for my texture map painting, including tertiary displacement detail (skin pores, fine wrinkles, fabric texture). While the color maps are usually a mix between hand painting and layering photographed, flatly lighted elements, I have started basing my skin displacement detail on skin scans. After purchasing a scan set (usually .tiff files), I color correct them in Photoshop to give me suitable maps to paint from. These tend to work much better than what you can get from just color correcting a standard photo, where things like skin pigmentation can give you flawed shape information.

在MARI獨立紋理繪畫

我使用MARI進行紋理貼圖，包括三位置細節(jié)（皮膚毛孔，細紋，織物紋理）。 雖然彩色地圖通常是手繪和分層照片之間的混合，平面照明的元素，我已經(jīng)開始基于我的皮膚位移細節(jié)在皮膚掃描。 在購買掃描集（通常.tiff文件）后，我將在Photoshop中對它們進行顏色校正，以給出適合的地圖繪制。 這些傾向比通過顏色校正標準照片獲得的效果要好得多，皮膚色素沉著可以讓您產(chǎn)生有缺陷的形狀信息。

Render scene setup

This is the stage where I import all of the low resolution meshes into Maya and start testing the displacements. The main challenge here is layering the two sets of displacement maps. Since the maps from ZBrush are 32bit files with no displacement at zero (black), and those from MARI are 8bit files with zero displacement at 0.5, some normalization of values is needed. I do this by shifting the MARI map values down using a HSV Remap node, followed by a Multiply node to control the overall strength. The two map sets are then merged using a +/- Average node.

渲染場景設(shè)置

這是我將所有低分辨率網(wǎng)格導(dǎo)入Maya并開始測試位移的階段。 這里的主要挑戰(zhàn)是分層兩套位移圖。 由于ZBrush的映射是32位文件，沒有位移為零（黑色），而MARI的文件是8位文件，位移為0.5，需要進行一些規(guī)范化。 我通過使用HSV Remap節(jié)點向下移動MARI映射值，然后使用“Multiply”節(jié)點來控制整體強度。 然后使用+/-平均節(jié)點合并兩個地圖集。

Taking notes from classical photography

When the displacement is working, I pretty much finalize the lighting. I am a big fan of taking notes from real life photography when planning portrait lighting in particular. Many websites such as Digitalcameraworld.com have great guide charts for classical lighting schemes. Here I used a simple 2-light setup using an Arnold area light as the key light, and another, smaller area light as a combination fill light/rim light. I also added an Ai Skydome light with an HDRi attached, but on very low exposure as I only wanted to break up the Specular hits a little.

古典攝影記錄

當位移工作時，我?guī)缀跬瓿闪苏彰鳌?/span> 特別是規(guī)劃肖像照明時，我是從現(xiàn)實生活中拍攝筆記的大粉絲。 許多網(wǎng)站，如Digitalcameraworld.com有很好的指南圖表古典照明方案。 在這里，我使用一個簡單的2光設(shè)置，使用阿諾德地區(qū)光作為關(guān)鍵燈，另一個較小的區(qū)域光作為組合填充光/邊框燈。 我還添加了一個帶有HDRi的Ai Skydome燈，但是曝光非常低，因為我只想打破鏡頭點擊。

Building shaders

The last step is also the most time consuming. Setting up skin shaders in particular is lots of trial and error, and test renders take time. You might also find that you have to go back and tweak some of your texture maps at this point to get the desired result. Keep in mind that Arnold is a physically plausible renderer, so the scale of your model has to be correct for the shaders to behave properly.

設(shè)置著色器

最后一步也是最耗時的。 特別設(shè)置皮膚著色器是很多的嘗試和錯誤，測試渲染需要時間。 您也可能會發(fā)現(xiàn)，您必須回去并調(diào)整一些紋理貼圖才能獲得所需的結(jié)果。 請記住，阿諾德是一個物理上可行的渲染器，所以您的模型的規(guī)模必須是正確的，以使著色器的行為正確。

Finishing up

After having all of the shaders set up and looking good, the only thing left is to crank up the sampling quality and let Arnold start working away at the final render. For this project I wanted to get as close to final result directly in the beauty render, so what I ended up with is just the plain render with some minor color correction and level adjustments applied to it in Photoshop. The frame was rendered as a linear 32bit .exr file, which gave me all the dynamic range I needed to do whatever color and value adjustments necessary in Photoshop.

整理

在所有的著色器設(shè)置和看起來不錯之后，剩下的唯一的事情就是調(diào)整采樣質(zhì)量，讓Arnold在最后的渲染中開始工作。 對于這個項目，我想直接在美容渲染中得到最終結(jié)果，所以我最后得到的只是在Photoshop中應(yīng)用了一些小的顏色校正和級別調(diào)整的簡單渲染。 該框架呈現(xiàn)為一個線性32位的.exr文件，它給了我所有的動態(tài)范圍，我需要在Photoshop做顏色和價值調(diào)整。