第12章 UVs & Textures

UVs & Textures貼圖和紋理

To make 2D maps fit properly onto 3D objects, UV coordinates can be used to define a flattened view of your geometry. When you first create any geometry it will not have any UVs. Even primitive objects do not have any built-in UVs. This means that you will need to add them at the geometry level using one or more SOP nodes.

要使2D貼圖適當地適合3D對象，可以使用UV坐標來定義幾何體的展平視圖。 首次創建任何幾何體時，它將不會有任何UV。 即使是原始對象也沒有任何內置的UV。 這意味著您需要使用一個或多個SOP節點在幾何級別添加它們。

UV QUICKSHADE

When you first start adding UVs to your geometry a UV Quickshade node will set up some projected UVs, which you will probably replace with a subsequent UV node, as well as assign a UVgrid texture that you can use to evaluate your work. Later when you want to assign a real texture map to the object, you may want to bypass or delete this node to hide the UV grid.

當您第一次開始向幾何體添加UV時，UV Quickshade節點將設置一些投影UV，您可能會將其替換為後續UV節點，以及指定可用於評估工作的UVgrid紋理。 稍後，當您想要為對象指定真實紋理貼圖時，您可能希望繞過或刪除此節點以隱藏UV網格。

UV PROJECT貼圖項目

Assign UVs using one of several projection techniques. Once you choose your projection type you can then 「initialize」 the projection to match your object. This may invert the UVs and you may need to a transform value such as -90 instead of 90 for rotate x. This method only works for the simplest cases and will cause distortion in models that have more organic shapes.

使用幾種投影技術之一指定UV。 選擇投影類型後，您可以「初始化」投影以匹配您的對象。 這可能會反轉UV，您可能需要轉換值，例如-90而不是90，用於旋轉x。 此方法僅適用於最簡單的情況，並會導致具有更多有機形狀的模型失真。

UV FLATTEN

UV Flatten unwraps your geometry based on predefined boundaries based on selected edges or edge groups. The results can then be tweaked by pinning points in the UV view and adjusting the islands to get the look you want.

UV Flatten根據基於選定邊或邊組的預定義邊界展開幾何體。 然後可以通過在UV視圖中固定點並調整島嶼來調整結果以獲得所需的外觀。

UV EDIT

To edit individual vertices or groups of vertices you will use either the UVedit or UVtransform nodes. The UVedit node lets you perform many edits using a single node while UVtransform allows one edit per node which can provide a more procedural result. You can use Display > UV Distortion from the UV Viewport menu to see whether you are editing too much.

要編輯單個頂點或頂點組，您將使用UVedit或UVtransform節點。 UVedit節點允許您使用單個節點執行許多編輯，而UVtransform允許每個節點進行一次編輯，這可以提供更多的程序結果。 您可以使用「UV視口」菜單中的「顯示」>「UV失真」來查看是否編輯過多。

UV LAYOUT

UV layout will let you create UV islands and pack them into UV space as efficiently as possible. This lets you maximize how much of a texture is being used on your geometry which is important when optimizing for both rendering and gameplay.

UV布局將允許您創建UV島並儘可能高效地將它們打包到UV空間中。 這使您可以最大化在幾何體上使用多少紋理，這對於渲染和遊戲玩法進行優化時非常重要。

You can use the region handle to put a the UV layout into a particular part of your UV space. Subsequent layouts can then work around this layout using the Pack Islands in Cavities option.

您可以使用區域手柄將UV布局放入UV空間的特定部分。 然後，後續布局可以使用「腔體中的包裝島」選項來解決此布局問題。

UDIMS

In addition to working with a Single UV tile, you can use UDIMs to spread your UVs over many tiles. This technique lets you create more detailed texture maps because your UV islands are not packed in too tight. Properly numbered texture maps will then be assigned to the appropriate tile.

除了使用單個UV圖塊之外，您還可以使用UDIM在多個圖塊上展開UV。 此技術可讓您創建更詳細的紋理貼圖，因為您的UV島不會太緊。 然後將適當編號的紋理貼圖分配給適當的貼圖。

UV ATTRIBUTES

Earlier you learned about how attributes can be assigned to geometry and carry important information that can be used down the line. UVs are vertex attributes that are used to wrap texture maps around your model and are created by the UV SOP nodes that you apply at the geometry level.

之前您了解了如何將屬性分配給幾何體並攜帶可以在線下使用的重要信息。 UV是頂點屬性，用於在模型周圍包裹紋理貼圖，並由在幾何級別應用的UV SOP節點創建。

These attributes are visualized in the UV viewport and analyzed in the geometry spreadsheet. These attributes work with various SOP nodes including the attribute wrangle node which lets advanced TDs manage their UVs using scripting.

這些屬性在UV視口中可視化，並在幾何電子表格中進行分析。 這些屬性適用於各種SOP節點，包括屬性爭用節點，它允許高級TD使用腳本管理其UV。

It is possible to create more than one UV set on the same geometry. When you use the UV nodes, you can set the UV attribute that you want to work with. By default this is uv but you could create a uv2 to create a second set. These different UV sets are used when you assign textures in VOPs so that different texture maps use different UV attributes to define their layout.

可以在同一幾何體上創建多個UV集。 使用UV節點時，可以設置要使用的UV屬性。 默認情況下，這是uv，但您可以創建一個uv2來創建第二個集合。 在VOP中指定紋理時，將使用這些不同的UV集，以便不同的紋理貼圖使用不同的UV屬性來定義其布局。

In the two images shown here, the first uses a toroidal projection and is assigned to a uv UV attribute while the second uses a planar projection and is assigned to a uv2 UV attribute. These UV attributes can have any name, for instance it could be bob instead of uv2.

在這裡顯示的兩個圖像中，第一個使用環形投影並分配給紫外UV屬性，而第二個使用平面投影並分配給uv2 UV屬性。 這些UV屬性可以有任何名稱，例如它可以是bob而不是uv2。

UV VIEWPORT MENU

The UV viewport menu lets you display UVs based on the UV attribute. You can also use this menu to figure out the background image which can either be the default UV grid or a texture map pulled from an assigned material.

「UV」視口菜單允許您根據UV屬性顯示UV。 您還可以使用此菜單確定背景圖像，該圖像可以是默認的UV網格，也可以是從指定材質中提取的紋理貼圖。

This menu also has display options for displaying UV Overlap, UV Backfaces and UV Distortion. These can be helpful when evaluating your UVs to decide if more tweaking is required.

此菜單還具有顯示UV重疊，UV背面和UV失真的顯示選項。 在評估UV時，這些可能會有所幫助，以決定是否需要進行更多調整。

ATTRIBUTE TRANSFER屬性轉移

One of the SOP nodes that can be used to manage attributes is Attribute Transfer which lets you take the UV attributes from one piece of geometry and transfer them based on proximity to another. This can be useful when the topology of a model has changed but you want to preserve some of the work you did creating UVs for the original model.

可用於管理屬性的SOP節點之一是屬性傳輸，它允許您從一個幾何體中獲取UV屬性，並根據與另一個幾何體的接近度傳輸它們。 當模型的拓撲發生變化但您希望保留為原始模型創建UV的一些工作時，這可能很有用。

SCENE VIEW | UVS 場景視圖uv

Current Tool - At the top of the Scene View, you will find the selected node when the Handle tool is active.

當前工具 - 在「場景視圖」的頂部，您可以在「處理」工具處於活動狀態時找到所選節點。

Background - The background of the main tile can be set using options found in the UV menu.

背景 - 可以使用UV菜單中的選項設置主圖塊的背景。

Outside Main Tile - polygons positioned in the area outside the main tile would overlap the same area on the main tile because the texture repeats unless you are using UDIMS which cover more than one tile.

外主平鋪 - 位於主平鋪外部區域的多邊形將與主平鋪上的相同區域重疊，因為紋理會重複，除非您使用覆蓋多個平鋪的UDIMS。

UV menu - When you are in the UV view, this menu gives you a number of different options for working with UVs.

UV菜單 - 當您處於UV視圖時，此菜單為您提供了許多用於處理UV的不同選項。

UV view - Use this menu to choose the UV view for this viewport.

UV視圖 - 使用此菜單為此視口選擇UV視圖。

Layout Handle - This handle is part of the UV Layout node and lets you focus the UVs to a certain part of the tile.

布局句柄 - 此句柄是「UV布局」節點的一部分，可讓您將UV聚焦到圖塊的某個部分。

Pack Around - The UV layout will pack your UVs around any existing geometry that has already had its UVs set.

Pack Around - UV布局將UV包裝在已設置UV的任何現有幾何體周圍。