植被：创作技巧

Set the visibility distances for LODs by enabling the Combine By Postfixes option and adjusting values in the import settings.设置可见距离细节层次通过启用 Combine By Postfixes 选项并调整导入设置中的值。

Shadow LOD

阴影细节层次#

If the Import Materials flag was enabled in the import options, all necessary materials are already generated and assigned to the surfaces of the tree. Let's consider material parameters that worth being noted:如果在导入选项中启用了 Import Materials 标志，则所有必要的材质都已生成并分配给树的表面。让我们考虑一下值得注意的材质参数：

• Make the leaves material Alpha-Test to cut out texels according to the Alpha channel of the Albedo texture.使叶子材质为 Alpha-Test，以根据 Albedo 纹理的 Alpha 通道切出纹素。

• If specular highlights are incorrect, it is recommended to set the Specular value to 0.如果镜面高光不正确，建议将 Specular 值设置为 0。

  

  Incorrect lighting on the Reflections Rendering Debug preview (left) and the result image (right)反射渲染调试预览（左）和结果图像（右）上的照明不正确

• Consider enabling the Two Sided option for the material to make the foliage denser. Be careful, as it may significantly affect performance if there are too many polygons in the scene.考虑为材质启用 Two Sided 选项以使树叶更密集。请小心，因为如果场景中的多边形过多，可能会显着影响性能。

  It may be better to switch the Backside Normal mode to the To Front Side option since it usually provides more realistic results for foliage.将 Backside Normal 模式切换到 To Front Side 选项可能会更好，因为它通常会为植物提供更真实的结果。

• If textures make it evident that foliage is made of flat chunks, a great solution to this is the Angle Fade feature that cuts out polygons faced to the camera at extreme angles.如果纹理表明树叶是由扁平的块组成的，那么一个很好的解决方案是 Angle Fade 功能，它以极端角度切出面向相机的多边形。

  

  注意

  This feature may work incorrectly for meshes that have modified normals.对于已修改法线的网格，此功能可能无法正常工作。

• Adjusting translucency for the foliage material is necessary for a better look. Increase the Translucent value to permit light to pass through the object.调整树叶材质的半透明度对于更好的外观是必要的。增加 Translucent 值以允许光线穿过对象。

  

  You can also enable the use of the Translucent Map in the States tab to specify a single-channel texture that will define parts of the object that aren't translucent (such as branches).您还可以启用在 States 选项卡中使用 Translucent Map 来指定单通道纹理，该纹理将定义对象的非半透明部分（例如分支）。

  注意

  There is no need to paint fibers and small features of leaves on the Translucent texture if the Normal map is used and defines such surface irregularities.没有必要在半透明纹理上绘制纤维和叶子的小特征，如果普通的使用地图并定义此类表面不规则性。

  Albedo texture反照率纹理

  Translucent texture半透明纹理

• Enable the Terrain Lerp flag for the material of the bottom part of the tree to blend your tree with a Terrain in your scene.为树底部的材质启用 Terrain Lerp 标志，以将您的树与地形在你的场景中。

  

The fact that foliage is composed of flat chunks results in inaccurate shading. To counteract this and hide the flatness of the mesh, adjust vertex normals and affect the foliage is shaded.树叶由扁平块组成的事实导致不准确的阴影。要抵消这一点并隐藏网格的平整度，请调整顶点法线并影响树叶的阴影。

The following solutions are possible:以下解决方案是可能的：

• Enable the Normals Rotated To Camera option so all surface normals will be oriented towards the camera, ignoring the geometry normals. This feature checks out as a quick solution, although it makes all polygons shaded the same way.启用 Normals Rotated To Camera 选项，以便所有表面法线将朝向相机，忽略几何法线。此功能作为一种快速解决方案进行了检查，尽管它使所有多边形都以相同的方式着色。

  

• Edit vertex normals manually in your modeling software. Transfer vertex normals from a boundary cage to make the foliage look like a smooth and dense tree crown.在建模软件中手动编辑顶点法线。从边界笼子转移顶点法线，使树叶看起来像一个光滑而密集的树冠。

  注意

  It is recommended to use a dome-like boundary cage with the sides elongated to the ground to avoid shading errors on lower polygons.建议使用圆顶状的边界笼，边向地面拉长，以避免较低多边形上的着色错误。

  

  Transferring normals from a boundary cage从边界笼转移法线

  As a result, the flatness of foliage geometry is less evident (on the right):结果，树叶几何形状的平整度不太明显（右侧）：

  

The MipMapping technique, supported by UNIGINE renderer, implies sampling lower textures for smaller and distant polygons. At that, minor features of foliage start wiping away with the distance. In some cases, branches and leaves look thicker when far from the camera than on a close-up view.UNIGINE 渲染器支持的MipMapping技术意味着对较小和较远的多边形采样较低的纹理。那时，树叶的次要特征开始随着距离而消失。在某些情况下，远离相机时树枝和树叶看起来比近距离观察时更粗。

MIP mapsMIP 映射

This issue can be resolved via these approaches:可以通过以下方法解决此问题：

• Engage the Mip Bias feature to shift the distance at which the switch between MIP-levels is performed. This option significantly affects the performance.使用 Mip Bias 功能来移动执行 MIP 级别之间切换的距离。此选项会显着影响性能。
• By default, MIP maps for a texture are generated automatically on import using the Box filtering that may provide too blurred results. Consider switching to the Point filtering type to get sharper MIP maps.默认情况下，纹理的 MIP 贴图在导入时使用 Box 过滤自动生成，这可能会提供过于模糊的结果。考虑切换到 Point 过滤类型以获得更清晰的 MIP 映射。

• You can also prepare custom MIP maps in third-party software. For example, here is a comparison between MIP maps generated using the Box filtering and the sharper Kaiser filtering:您还可以在第三方软件中准备自定义 MIP 映射。例如，下面是使用 Box 过滤和更清晰的 Kaiser 过滤生成的 MIP 图之间的比较：

  

  To import a texture with custom MIP-levels, use the Combine option for a texture with laid out MIP-levels or save them to a .texture format and import the texture with the Unchanged option enabled.要导入具有自定义 MIP 级别的纹理，请对具有布局 MIP 级别的纹理使用 Combine 选项，或将它们保存为 .texture 格式并在启用 Unchanged 选项的情况下导入纹理。

Stem animation applies vertex movement based on spatial 3D noise to simulate bending of the plant's trunk or stem caused by wind. The mesh's pivot point is considered fixed, and the further the vertex is along the Z axis, the stronger movement is applied to it.茎动画应用基于空间 3D 噪声的顶点运动来模拟由风引起的植物树干或茎的弯曲。网格的枢轴点被认为是固定的，顶点沿 Z 轴越远，对其施加的运动就越强。

Thus, it is necessary to place the pivot point at the correct position (usually, it is the bottommost point of the stem) and orient the model, so the Z axis goes upwards.因此，需要将枢轴点放置在正确的位置（通常是杆的最底部）并定位模型，使 Z 轴向上。

Stem animation example茎动画示例

A set of Parameters controls the animation.一套参数控制动画。

Please make note that all surfaces of the plant must have identical stem animation parameters in order to synchronize their movement.请注意，植物的所有表面必须具有相同的茎动画参数才能同步它们的运动。

Different stem animation parameters result in not synchronized parts of the tree不同的茎动画参数导致树的部分不同步

The Leaves animation is another layer of vertex shader animation mainly applied to foliage, providing additional detail bending. Using this type of animation requires preliminary adjustment to geometry on the modeling stage.树叶动画是另一层顶点着色器动画，主要应用于树叶，提供额外的细节弯曲。使用这种类型的动画需要在建模阶段对几何形状进行初步调整。

Several approaches of leaves animation are available out of the box. Choose the type of animation using the Leaves option.几种方法叶子动画开箱即用。使用 Leaves 选项选择动画类型。

Geometry Vertex Color Based

基于几何顶点颜色#

This recommended approach providing the best control over foliage implies that leaves are rendered as polygons, and vertex colors are used for animation.这种提供对树叶的最佳控制的推荐方法意味着树叶被渲染为多边形，并且顶点颜色用于动画。

Vegetation movements are defined by RGB channels of vertex colors as follows:植被运动由顶点颜色的 RGB 通道定义，如下所示：

	Red channel is used for animation of smaller or peripheral parts of vegetation (leaves). Bright parts are animated, and dark parts are stiff.红色通道用于植被（叶子）的较小或外围部分的动画。明亮的部分是动画的，而黑暗的部分是僵硬的。
	Green channel is used to define the movement order for branches in order to desynchronize them. The movement sequence starts from the brightest element to the darkest.绿色通道用于定义分支的移动顺序，以使它们不同步。运动顺序从最亮的元素开始到最暗的元素。
	Blue channel is used to define which parts of branches can be bent. Brighter parts indicate bendable portions, and darker parts — stiff portions.蓝色通道用于定义分支的哪些部分可以弯曲。较亮的部分表示可弯曲部分，而较暗的部分   -   较硬的部分。

The animation parameters control vertices movement:这动画参数控制顶点移动：

It is also a regular practice to animate branches using this technique even if they are attached to the trunk:即使分支连接到树干，使用此技术为分支设置动画也是一种常规做法：

The Green and Blue channels define the movement of vertices; the Red channel is not used for branches绿色和蓝色通道定义顶点的移动；红色通道不用于分支

At that, related surfaces must have the same vertex colors on adjacent vertices and identical animation parameters in order to synchronize their movement:此时，相关曲面必须在相邻顶点上具有相同的顶点颜色和相同的动画参数，以便同步它们的运动：

The colors of adjacent vertices of the trunk and foliage are the same, so the geometry stays connected when animated树干和树叶相邻顶点的颜色相同，因此动画时几何体保持连接

Geometry Vertex Color Based leaves animation基于几何顶点颜色的叶子动画

Geometry UV-based

几何基于 UV#

This is a rather legacy approach when leaves are rendered as standard polygons. It requires the UV Channel 2 to be defined for the mesh.当叶子被渲染为标准多边形时，这是一种相当传统的方法。它需要为网格定义 UV 通道 2。

Geometry UV-based animation基于 UV 的几何动画

UV Channel 2: the stiffest vertices are in the top left cornerUV 通道 2：最硬的顶点在左上角

Animation uses UV channel 2 of an object as follows: in the UV grid, [0,1] is the pivot point for the object's movements and the stiffest part of the object, and towards [1,0], the object becomes more flexible.动画使用物体的UV通道2如下：在UV网格中，[0,1]是物体运动的轴心点，也是物体最硬的部分，朝向[1,0]，物体变得更加灵活.

Control the vertices movement via the same Animation Parameters.通过相同的控制顶点移动动画参数.

Billboard

Billboard#

Billboard is the most performance-friendly way of animating distant vegetation: all quads are rendered as billboards that always face the camera; the UV Channel 2 defines the size and movement of polygons. Hence, the foliage mesh should contain only quad polygons for leaves.Billboard 是对远处植被进行动画处理的最性能友好的方式：所有四边形都被渲染为始终面向相机的 billboards； UV 通道 2 定义了多边形的大小和运动。因此，树叶网格应该只包含树叶的四边形。

A billboards-based bush基于广告牌的灌木

The mesh of the bush灌木的网格

Animation uses UV channel 2 of an object as follows: in the UV grid, [0,1] is the pivot point for the billboard's movements, and the billboard's size can be changed by scaling the polygon in the UV channel.动画使用对象的UV通道2如下：在UV网格中，[0,1]是广告牌运动的轴心点，可以通过缩放UV通道中的多边形来改变广告牌的大小。

UV Channel 1紫外线通道 1

UV Channel 2紫外线通道 2

Mesh (above) and the result (below)网格（上）和结果（下）

Control the polygons movement via the same Animation Parameters.通过相同的控制多边形运动动画参数.

Stem and leaves animation are also controlled by the global Vegetation Animation Parameters. Via these settings, you can adjust stem and leaves animation intensity, speed, and wind effect globally and control the weather conditions per world.茎叶动画也由全局控制植被动画参数.通过这些设置，您可以全局调整茎叶动画强度、速度和风效果，并控制每个世界的天气状况。

Note that the global parameters are just multipliers for the per-material animation parameters.请注意，全局参数只是每个材质动画参数的乘数。