第11章 Shaders & Materials

Shaders & Materials著色器和材料

To render objects in your scene, you must assign materials, also known as shaders, to your geometry. In Houdini, these materials and shaders are created in the mat and vex builder networks. The ability to build up your materials using nodes is a powerful tool when defining the look of a shot.

要在場景中渲染對象，必須將材質（也稱為著色器）指定給幾何體。 在Houdini中，這些材質和著色器是在mat和vex構建器網路中創建的。 在定義鏡頭外觀時，使用節點構建材質的能力是一個強大的工具。

Houdini organizes different types of nodes into network types and for materials you will use the /mat network. This is where you can set up VEX operators or VOPs. You can either work with pre-built shaders or build your own by using a custom network of VOP nodes.

Houdini將不同類型的節點組織成網路類型，並將材料用於/ mat網路。 您可以在此處設置VEX運算符或VOP。 您可以使用預先構建的著色器，也可以使用VOP節點的自定義網路構建自己的著色器。

CREATING AND ASSIGNING MATERIALS創建和分配材料

You can add materials using the Material Palette then assign them to objects by clicking and dragging. This pane has a workspace for managing the materials in your scene which is organized into tabs that represent different subnetworks where material nodes can be created. This pane gives you a flattened view of all of the materials in your scene, so they can easily be found in whichever subnetwork they are located.

您可以使用材質選項板添加材質，然後通過單擊並拖動將它們分配給對象。 此窗格有一個工作區，用於管理場景中的材質，該工作區組織為表示可以創建材質節點的不同子網的選項卡。 此窗格為您提供場景中所有材質的展平視圖，因此可以輕鬆找到它們所在的子網。

THE MATERIAL GALLERY材料庫

On the left side of the palette is the gallery where you will find pre-built materials that you can assign to your objects. You can assign a material directly from the gallery to the viewport or you can move it to area on the right and assign it later. As you learn how to create your own materials, you can build custom galleries and add them to this list.

在調色板的左側是圖庫，您可以在其中找到可以分配給對象的預構建材料。 您可以直接從庫中將材質指定給視口，也可以將其移動到右側區域並稍後分配。 在學習如何創建自己的材料時，您可以構建自定義圖庫並將其添加到此列表中。

PRINCIPLED SHADER原則陰影

In the Material Palette, you will find the principled shader, a material based on the Disney 「principled」 BRDF by Brent Burley. This shader is 「principled」 rather than physical in order to make it easier for artists to work with.

在Material Palette中，您將找到原則著色器，這是一種基於Brent Burley的迪士尼「原則」BRDF的材料。 這個著色器是「原則的」而不是物理的，以便讓藝術家更容易使用。

The Principled Shader has been pre-built to include the ability to assign textures directly and set up with other features such as bumps, normals, displacements and more. The texture maps you assign will be displayed in the viewport and you can achieve a wide variety of looks right out of the box.

Principled Shader已經預先構建，包括直接分配紋理和設置其他功能（如凸起，法線，位移等）的功能。 您指定的紋理貼圖將顯示在視口中，您可以立即實現各種各樣的外觀。

You can extend this material by feeding it with other VOPs but that isn』t necessary in all cases. Many of the materials found in the gallery are variations on this shader.

您可以通過將其與其他VOP一起提供來擴展此材料，但這並非在所有情況下都是必需的。 在圖庫中找到的許多材料都是此著色器的變體。

PRINCIPLED SHADER CORE原則的陰影核心

The Principled Shader Core node sits inside the Principled Shader and contains the main features of the shading model but doesn』t have all of the texturing features built-in.

To build a robust shader from scratch using this node, you would need to add VOP nodes using Houdini』s shader building tools. You can accomplish this by either wiring together nodes in the Node view or adding them using the Shader FX menus.

Principled Shader Core節點位於Principled Shader內部，包含著色模型的主要功能，但沒有內置的所有紋理功能。

要使用此節點從頭開始構建強大的著色器，您需要使用Houdini的著色器構建工具添加VOP節點。 您可以通過將節點視圖中的節點連接在一起或使用Shader FX菜單添加它們來實現此目的。

LAYERING MATERIALS層狀材料

At the /mat level, you can layer materials to create a unique look for your object. Using a Layer Mix node, you can combine two different materials into a single look. For instance, a shiny metal material and a matte rust material can be layered using this technique. You can then texture an alpha channel and you can choose to mix the surface, the displacement or both.

在/ mat級別，您可以對材質進行分層，以便為對象創建獨特的外觀。 使用「圖層組合」節點，您可以將兩種不同的材質組合成一個外觀。 例如，可以使用該技術層疊閃亮的金屬材料和無光澤的防鏽材料。 然後，您可以設置Alpha通道的紋理，您可以選擇混合曲面，位移或兩者。

MATERIAL BUILDER材料製造商

If you want to turn your layered nodes into a new material then you can select them and choose Edit > Collapse Selected into Material. This puts the nodes inside a material builder where you can continue to tweak it. At this level, there are output and collect nodes to make the network work efficiently.

如果要將分層節點轉換為新材質，則可以選擇它們並選擇「編輯」>「摺疊選定到材質」。 這會將節點放在材料構建器中，您可以在其中繼續調整它。 在此級別，有輸出和收集節點，以使網路有效工作。

MATERIALS AS DIGITAL ASSETS作為數字資產的材料

You can make materials even more efficient by saving them out as Houdini Digital Assets. In the Asset Properties pane, you can go to the Save tab and choose Save Cached Code so that the material is pre-compiled when you render with Mantra. HDA』s make it easier for you to share materials with your team.

您可以將材料保存為Houdini Digital Assets，從而提高材料效率。 在「資產屬性」窗格中，您可以轉到「保存」選項卡並選擇「保存緩存代碼」，以便在使用Mantra進行渲染時預編譯材料。 HDA使您可以更輕鬆地與團隊共享資料。

SHADER FX MENU

While working with material VOPs, you can add nodes in the Node view and wire them in or you can access the Shader FX Menu by clicking on the icon at the far right of each parameter. This menu lets you focus on the parameter that you want to work with and choose the appropriate node in context.

使用材質VOP時，您可以在「節點」視圖中添加節點並將其連接，也可以通過單擊每個參數最右側的圖標來訪問Shader FX菜單。 通過此菜單，您可以專註於要使用的參數，並在上下文中選擇適當的節點。

In the Parameter Pane, you can see what type of connection each has by looking at the icon on the far right:

在參數窗格中，您可以通過查看最右側的圖標來查看每種連接的類型：

No Connection無連接

Parameter Node參數節點

Connected with other Nodes與其他節點連接

Hidden Connection隱藏連接

OTHER WAYS TO ASSIGN MATERIALS其他分配材料的方法

Materials can be assigned to the object where it will be listed under the Render tab. There is also a Material SOP which allows you to assign materials to part of a model at the geometry level. You will oft en use groups to make it easier to assign materials this way.

可以將材質指定給將在「渲染」選項卡下列出的對象。 還有一個材質SOP，允許您在幾何級別將材質指定給模型的一部分。 您將不得不使用組來更輕鬆地以這種方式分配材料。

The Data Tree panel gives you access to Material stylesheets which you can use to assign materials and textures to large groups of objects or imported Alembic files. This is a production-level tool that makes it more efficient for artists to work with large shots. Refer to the Houdini docs for more information.

通過「數據樹」面板，您可以訪問「材質」樣式表，您可以使用這些樣式表將材質和紋理分配給大型對象組或導入的Alembic文件。 這是一個生產級別的工具，可以讓藝術家更有效地使用大型鏡頭。 有關更多信息，請參閱Houdini文檔。

MATERIAL PALETTE 材料PALETTE

Material in Gallery - The Materials listed here are saved to disk in a gallery file. You can drag these into the scene area found on the right or onto objects in the viewport to assign them.

圖庫中的材質 - 此處列出的材質將保存到圖庫文件中的磁碟中。 您可以將它們拖動到右側的場景區域或視口中的對象上以進行分配。

Material in Scene - This is where you find materials that are part of your scene file. They can be assigned to objects by dragging from here into the viewport.

場景中的材質 - 您可以在此處找到場景文件中的材質。 可以通過從此處拖動到視口來將它們分配給對象。

Material Gallery - There are some default galleries that come with Houdini. You can build your own and add them to this area for your own projects.

材料庫 - Houdini附帶了一些默認的圖庫。 您可以構建自己的項目並將它們添加到此區域以用於您自己的項目。

Assign Material - If you select your object in the scene and the material in the palette then you can use this butt on to assign the material.

指定材質 - 如果選擇場景中的對象和選項板中的材質，則可以使用此對接來指定材質。

Double Click to Edit - If you double-click on any of these materials, you will jump to a Node View where you can make edits at the /mat level.

雙擊編輯 - 如果雙擊任何這些材料，您將跳轉到節點視圖，您可以在/ mat級別進行編輯。

Material Subnets - Sometimes a material subnet is used to keep materials relative to the geometry they are being assigned to. All of the subnets in your scene will be listed here.

物質子網 - 有時，物料子網用於保留與分配給它們的幾何體相關的材料。 此處將列出場景中的所有子網。

SHADER BUILDING

Node Path - This will confirm your current path and help you navigate into and out of the material network.

節點路徑 - 這將確認您當前的路徑並幫助您導航進出物料網路。

VOP Nodes - In the material context you can start with material nodes then wire in VOP nodes to customize the texturing of the material. Once you are finished you can choose to collapse all of this back into a single material.

VOP節點 - 在材質上下文中，您可以從材質節點開始，然後在VOP節點中連接以自定義材質的紋理。 完成後，您可以選擇將所有這些摺疊回單個材質中。

Node Connectors - You can add nodes to this area using the Shader FX menu which is can be accessed by MMB-clicking on the dot. RMB-clicking on the dot gives you a full node menu.

節點連接器 - 您可以使用Shader FX菜單將節點添加到此區域，可以通過MMB點擊該點來訪問該菜單。 人民幣點擊點可以獲得完整的節點菜單。

Principled Material - This is a typical material which could be assigned on its own or fed into the Layer mix.

原則材料 - 這是一種典型的材料，可以單獨分配或輸入層混合物。

Layer Mix - The Layer output on the materials can be fed into this mix node. You can assign this to your geometry.

層混合 - 材料上的層輸出可以饋入此混合節點。 您可以將其指定給幾何體。

Material Flag - If you want the layer mix to show up in the material palette then check this flag.

材料標記 - 如果希望圖層混合顯示在材質調色板中，請選中此標記。

Alpha - Here the layer mix node』s alpha is being fed by VOP nodes to create the alpha mask for the two layered materials.

Alpha - 這裡層混合節點的alpha由VOP節點饋送，以創建兩層材料的alpha掩碼。

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