Maya Nurbs 車輪建模的流程解析

2020-10-20 19:00:14

字體：大中小

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　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，知識教程是英文教程，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教程，我并不翻譯其中一些命令，這樣可以讓一些初學者 ( 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，所以在翻譯的時候會有一些不足之處，如果有讓你發笑的地方，請你給我提醒，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，創建圓滑的曲線 ( 如 pic 0 所示 ). 在這個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.

　　現在選擇第二條圓環曲線 (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), 這一點非常重要，因為我們需要一個非常精確的曲面。

　　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 (pic 3) 將其在 -z 軸方向拉伸 (pic 4), 數值約為 -0.235. 你可以在 channel box 里看到這一數值。

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

　　選擇 9 個 cv 點 (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 -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 出來是應該椒 nurbs 曲面，打開你的 extrude 選項，設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.

　　在進入 fillet 及 trim 的工作之前，有一些很重要的事情我們應該了解一下 maya 的鑲嵌的圓滑設置 .

　　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 的人都會造成此類現象。

　　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.

　　當你在使用 nurbs 做一些 fillet 和 trim 的工作時，在全局渲染里將預視圖設為產品質量 (production quality) 是很重要的 . 雖然它只是預視圖，產品質量 (production quality) 可以圓滑縫合點 . 抗鋸齒 (anti-alias) 在 maya 里的設置，對 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，我們可以通過對抗鋸齒的設置來改善它 .

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

　　讓我們談談鑲嵌的問題，你可以選擇這 3 個選項中的一個或三個都選來設置 :

　　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，確認你的 positional tolerance( 在 circular fillet 選項里 ) 是否已經設置到最小的值，以便在兩個要 fillet 的曲面中得到最好的結果，你可以設為 0.010( 缺省就是 0.010), 同樣你也可以將 tangent tolerance 設為 0.0100, 在這種設置下， maya 可以在嚴謹的連接兩個曲面 .

　　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 會自動創建 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 場景，你必需要做的是選擇你所有的 nurbs 物體，到你的 render menu 里設置 nurbs 鑲嵌，然后渲染場景，它可以減少縫隙 . 它會增加你的渲染時間和內存，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. 當你每次完成 fillet 和 trim 操作，選擇已被 fillet 和 trim 過的物體設置它們的 advanced tessllation 屬性，將 uv 設為 20x20(pic 14), 不要忘記在全局渲染里設置產品質量 . 雖然不一定要到 20x20, 但是我認為這是一個比較好的數值 , 請你注意使用這個方法，它會增加你的渲染時間 .

　　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

　　但我認為你會使用 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，一定要在選項框中選擇在表面創建曲線，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 的值設為 -0.03( 有可能 circular fillet 的值會設為另一方向，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 : 如果你發現你的尺寸大了，那么使用一個更小的值 ; 我想說的是，在開始做之前，應該檢查它們的尺寸。

　　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 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，我取值為 -0.30, 小的取值為 -0.20.

　　create cap for logos

　　創建車輪蓋子

　　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，創建一個圓柱體并將它的尺寸在 xyz 軸縮小到 0.234, 旋轉 90 度 , 并將它移動到物體的中心 (pic 19) ，然后在 -z 軸上移動 -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).

　　調整前面的 cv 點到如 (pic 21) 的效果，調整好后，選擇最外面的 isoparm 線，使用 surfacesplanar 命令閉合這個車輪蓋子 (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, 現在你可以將所有的補助線隱藏起來，選擇所有物體，并給它們一個缺省的 phonge 材質，調整 phonge 材質的主顏色 (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 設為 highest value , 將 u 和 v division facto 設為 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...

　　確認你在全局渲染的設置里設置為產品質量 ( 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...!!!