本教程向朋友們介紹Maya Nurbs 車輪建模的流程，教程介紹的很詳細(xì)，知識(shí)教程是英文教程，感興趣的朋友可以慢慢閱讀一下！

　　為了讓大家更能理解這個(gè)教程，我并不翻譯其中一些命令，這樣可以讓一些初學(xué)者 ( 不是很熟悉 maya nurbs 建模命令 ) 更快找到這些命令。另：我的英文不好，所以在翻譯的時(shí)候會(huì)有一些不足之處，如果有讓你發(fā)笑的地方，請(qǐng)你給我提醒，我將更改過來 , 我的 email: chinacache@163.com.

　　希望可以和大家一同進(jìn)步！?。。?！

openyour maya, expand front view, then create a wheel pattern with shapes/curves like in the following image (pic 0). for this tutorial i use working units (cm) with object size around 3.927 (pic 1), this measurement affects every xyz axis number in this tutorial, but you could choose your own measurement, e.g. 3.9or4.

　　打開你的 maya, 切換到 front 視圖，創(chuàng)建圓滑的曲線 ( 如 pic 0 所示 ). 在這個(gè)教程里我使用厘米作為單位，車輪的直徑為 3.927( 如 pic 1), 這個(gè)尺寸在 xyz 軸上都是有效的，你可以自己選擇你喜歡的尺寸，如 3.9 或 4.

　　nowselectsecond circle shapes (pic 1a), then surface planar. and then edit nurbs rebuild surfaces, open option box and enter 8x8 for uv spans (pic 2) , this rebuild surface step is important #39;cause we needa high-resolution nurbs for this main front object.

　　現(xiàn)在選擇第二條圓環(huán)曲線 (pic 1a), 使用 surface planar 命令 . 然后使用 edit nurbsrebuild 命令重建曲面，改變曲面 uv 度為 8x8(pic 2), 這一點(diǎn)非常重要，因?yàn)槲覀冃枰粋€(gè)非常精確的曲面。

　　from front viewselectthese outer cv#39;s (pic 3) then drag to -z axis (pic 4), -z value its about -0.235. you could expand your cv information on the right panel to see the value.

　　在 front 視圖里選擇 cv 點(diǎn) (pic 3) 將其在 -z 軸方向拉伸 (pic 4), 數(shù)值約為 -0.235. 你可以在 channel box 里看到這一數(shù)值。

　　select these 9 center cv#39;s (pic 5) and drag also to -0.235 -z axis (pic 6).

　　選擇 9 個(gè) cv 點(diǎn) (pic 5) 將其在 -z 軸上拉 -0.235 的距離 (pic 6).

　　select these oval shapes (pic 7) and drag to about -0.46 of -z axis (pic 8).

　　選擇那些卵形的曲線 (pic 7) ，并在 -z 軸上移動(dòng) -0.46(pic 8).

　　now you have front oval shapes (bigger) and oval back shapes (smaller) right? ok nowselectevery set of oval shapes like in pic 9 and loft them (every set of them), then it would look like this pic (pic10).

　　先選擇大的卵形曲線，按住 shift 鍵選擇小形卵形曲線 (pic 9) ，一組一組的 loft 它們，然后就可得到如下圖的結(jié)果 (pic 10).

　　nowselectthe other shapes (triangle and small shapes in the center) (pic 11) and then extrude them to -0.5 of -z axis (pic 12). remember : to extrude a curve as nurbs, open your extrude option box andset the style to distance, and make sure output geometry has been set to nurbs

　　現(xiàn)在選擇其它曲線 ( 三角形和中心那些小圓 )(pic 11), 然后在 -z 軸上 extrude -0.5 的距離 .

　　記住 : extrude 出來是應(yīng)該椒 nurbs 曲面，打開你的 extrude 選項(xiàng)，設(shè)定距離并確定輸出的幾何體為 nurbs 曲面 .

　　

　　before entering this fillet amp; trim work, there is something important that we should know about preview resolution (antialias settings) and tessellation smoothness within maya.

　　在進(jìn)入 fillet 及 trim 的工作之前，有一些很重要的事情我們應(yīng)該了解一下 maya 的鑲嵌的圓滑設(shè)置 .

　　most of new maya users are shy of this nurbs gaps that are caused by fillet amp; trim works.

　　很多的使用 maya 的人都會(huì)造成此類現(xiàn)象。

　　when using nurbs with lots of fillet amp; trim works, it is important to preview the scene with production quality on render globals. even if it#39;s just a preview, production quality has soft multi-pixel filtering. anti-alias is important for nurbs with fillet amp; trim in maya. in this case, i am not talking about rebuilding the surfaces, but we could use smooth anti-alias combined with better tessellation settings to close the gaps.

　　當(dāng)你在使用 nurbs 做一些 fillet 和 trim 的工作時(shí)，在全局渲染里將預(yù)視圖設(shè)為產(chǎn)品質(zhì)量 (production quality) 是很重要的 . 雖然它只是預(yù)視圖，產(chǎn)品質(zhì)量 (production quality) 可以圓滑縫合點(diǎn) . 抗鋸齒 (anti-alias) 在 maya 里的設(shè)置，對(duì) fillet 和 trim nurbs 表面也是同樣重要 . 在這種情況下，我不是想說要重建表面，我們可以通過對(duì)抗鋸齒的設(shè)置來改善它 .

　　ok its about resolution preview, now about the tessellation problem, you can choose one of these 3 optionsorplay around with each settings :

　　讓我們談?wù)勮偳兜膯栴}，你可以選擇這 3 個(gè)選項(xiàng)中的一個(gè)或三個(gè)都選來設(shè)置 :

　　1. before circular filleting an object, be sure your positional tolerance (in circular fillet option box) has been set to minimal value for better tessellation between two surfaces, you could set it to 0.010 (the default is 0.0100), and also you can change the tangent tolerance to about 0.0100, with this option and value, maya will create more tightconnection between two surfaces.

　　1. 在 circular fillet 物體前，確認(rèn)你的 positional tolerance( 在 circular fillet 選項(xiàng)里 ) 是否已經(jīng)設(shè)置到最小的值，以便在兩個(gè)要 fillet 的曲面中得到最好的結(jié)果，你可以設(shè)為 0.010( 缺省就是 0.010), 同樣你也可以將 tangent tolerance 設(shè)為 0.0100, 在這種設(shè)置下， maya 可以在嚴(yán)謹(jǐn)?shù)倪B接兩個(gè)曲面 .

　　2. maya has built-in automatic nurbs tessellation check located in the render menu. if you want to render your nurbs scene, all you have todo isselectall of your nurbs objects, go to the render menu andselectset nurbs tessellation, apply this function, then render the scene, it will reduce the gaps automatically. this feature evaluates a set frame (s) and automatically determines the optimum tessellation settings, which results in smoother surfaces without over-tessellation (of course this saves time and memory).

　　2.maya 會(huì)自動(dòng)創(chuàng)建 nurbs 曲面的鑲嵌，你可以在 render menu 里查看它 . 如果你想渲染你的 nurbs 場(chǎng)景，你必需要做的是選擇你所有的 nurbs 物體，到你的 render menu 里設(shè)置 nurbs 鑲嵌，然后渲染場(chǎng)景，它可以減少縫隙 . 它會(huì)增加你的渲染時(shí)間和內(nèi)存，但是可以使你的曲面平滑 .

　　3. every time you#39;re finished with fillet amp; trim,selectyourtrimmed amp; filleted objects and set/turn on advanced tessellation andset number of uv to 20x20 (pic 14), and again, don#39;t forget to set your render globals to production quality. it doesn#39;t have to be 20x20, but i have found these to be good settings, but be carefull with this settings, the surfaces would very very smooth which increasing yourrendering times.

　　3. 當(dāng)你每次完成 fillet 和 trim 操作，選擇已被 fillet 和 trim 過的物體設(shè)置它們的 advanced tessllation 屬性，將 uv 設(shè)為 20x20(pic 14), 不要忘記在全局渲染里設(shè)置產(chǎn)品質(zhì)量 . 雖然不一定要到 20x20, 但是我認(rèn)為這是一個(gè)比較好的數(shù)值 , 請(qǐng)你注意使用這個(gè)方法，它會(huì)增加你的渲染時(shí)間 .

　　4. worst case; you can also add new lofted surface by lofting isoparm and trimmed surfaces between two separated surfaces

　　4. 如果遇上很糟糕的情況，你可以在兩個(gè)表面連接的地方之間增加你的 isoparm.

　　but i suggest you to use no.1 and no.2

　　但我認(rèn)為你會(huì)使用 no.1 和 no.2 來改善這種情況 .　anyway...please...don#39;t be to much worried about these gaps/space ..:) --- 不要太擔(dān)心這種情況 .

　　-----------------------------------------------

　　ha...still with me guys ?.....ok..let#39;s continue our wheel lesson

　　circular fillet amp; trim (part 1)

　　important : you must turn on create curve on surface on circular fillet option box, otherwise you cannot trim the surface.

　　重要 : 在你 circular fillet 時(shí)，一定要在選項(xiàng)框中選擇在表面創(chuàng)建曲線，否則你將不能剪切曲面 .

　　to circular fillet,selectlofted/extruded object first, thenselectmain body object, then circular fillet it, this would help us to remember the last settings of circular fillet directions.

　　cirular fillet 前，先選擇 loft/extrude 的曲面，然后再選擇主要的面， circular fillet 它們，這樣會(huì)讓我們記得 circular fillet 的方向 .

　　start circular fillet; in this case, i started with extruded triangle in the upper right area (pic 15). for this triangle, put a circular fillet with value of -0.03 on normal fillet direction (this circular fillet direction could be different, it depends on your u and vdirection). here#39;s after circular fillet and trim (pic 16)

　　開始 circular fillet: 在這里，我首先 circular 三解形曲面 (pic 15). 我將 circular fillet 的值設(shè)為 -0.03( 有可能 circular fillet 的值會(huì)設(shè)為另一方向，如 0.03 ，這取決于你的曲面 u 和 v 的方向 ).(pic 16) 是 circular fillet 后 trim 出來的結(jié)果 .

　　note : if your measurement is bigger than this tutorial, than use ahigher value; as i said in the beginning of this tutorial that measurement affects every xyz and of course this fillet value as well.

　　記住 : 如果你發(fā)現(xiàn)你的尺寸大了，那么使用一個(gè)更小的值 ; 我想說的是，在開始做之前，應(yīng)該檢查它們的尺寸。

　　next fillet and trim the oval lofted object, for this oval lofted object fillet, use reverse primary surface normal with radius of -0.03, (pic 17)

　　接下來 fillet 和 trim 卵形的曲面，我將 fillet 的值設(shè)為 -0.03.(pic 17).

　　do the same steps with the same settings for the other extruded andlofted objects (except inner objectsorsmall extruded objects) bellow.

　　然后重復(fù) circular 并 trim 這些三角形及卵形曲面 ( 中間的圓形曲面后面再做 ).

　　cirucular fillet amp; trim 2

　　for these small cylinder objects (pic 18) use reverse primary surface normal with value of -0.30 for bigger cylinders and -0.20 for smaller cylinders.

　　在 circular 比較大的圓形曲面時(shí)，我取值為 -0.30, 小的取值為 -0.20.

　　create cap for logos

　　創(chuàng)建車輪蓋子

　　from front view, create a nurbs cylinder and rescale it to 0.234 (xyz), rotate it to 90deg; , drag to the center of the objects (pic 19) and translate -z axis to -0.235 (pic 20).

　　在前視窗中，創(chuàng)建一個(gè)圓柱體并將它的尺寸在 xyz 軸縮小到 0.234, 旋轉(zhuǎn) 90 度 , 并將它移動(dòng)到物體的中心 (pic 19) ，然后在 -z 軸上移動(dòng) -0.235 的距離 (pic 20).

　　adjust the front cv#39;s until they look like in the following image (pic 21), thenselectoutter isoparm then surfaces planar to closethe cap (pic 22).

　　調(diào)整前面的 cv 點(diǎn)到如 (pic 21) 的效果，調(diào)整好后，選擇最外面的 isoparm 線，使用 surfacesplanar 命令閉合這個(gè)車輪蓋子 (pic 22).

　　next, you need to fillet the cap body with a value of 0.030 ( normal fillet direction ) (pic 23).

　　接下的，你需要 fillet 蓋子， circular fillet 的值為 0.030(pic 23).

　　ok, now you can hide all helper curves/shapes,selectall objects and apply a default phong-e material as soft steel and set the main color to just a little bit brighter than default (i.e. v=0.678) on hsv color sliders :)

　　ok, 現(xiàn)在你可以將所有的補(bǔ)助線隱藏起來，選擇所有物體，并給它們一個(gè)缺省的 phonge 材質(zhì)，調(diào)整 phonge 材質(zhì)的主顏色 (main color) ( 在 hsv 色板上 v 的取值約為 0.678).

　　final check before render :

　　渲染前的檢查 :

　　select editselectall by type nurbs surfaces , go to rendering module, go to render set nurbs tessellation option box , set the curvature tolerance to highest value , set the u and v division factor to 5, then hit set and close.

　　editselectall by type nurbs surfaces , 到 rendering module , 再到 render set nurbs tessellation option box , 將 curvature tolerance 設(shè)為 highest value , 將 u 和 v division facto 設(shè)為 5, 然后 set and close .

　　be sure your render global has been set to production quality (and raytracing if you want). now render it, you should have this lovely nurbs...

　　確認(rèn)你在全局渲染的設(shè)置里設(shè)置為產(chǎn)品質(zhì)量 ( 還有光線跟蹤 -- 如果你想的話 ), 然后渲染它，你將得到 ....

　　ooohh mommyyyy....its a brabussss...!!!

　?。ㄍ辏?/p>

　　教程結(jié)束，以上就是Maya Nurbs 車輪建模的流程解析方法介紹，操作很簡單的，大家學(xué)會(huì)了嗎？希望能對(duì)大家有所幫助！

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