FBX导入指南

To create several variations of one object with different level of detail (LODs) you should have them as separate surfaces of the object. This will allow you to reduce the number of nodes in the hierarchy and simplify the settings of the LODs visibility.为一个具有不同详细程度的对象创建多个变体（检出限），则应将它们作为对象的单独表面。这将允许您减少层次结构中的节点数量，并简化LOD可见性的设置。

UNIGINE provides automatic assignment and configuration of Levels of Detail based on the name postfixes, enabling you to create and export different meshes for different LODs of your model in a single FBX file. When naming these meshes, you should add a postfix to specify the LOD each mesh represents. You can also specify visibility and fade distances for each LOD of your model at the importing stage, saving time, as you don't have to adjust these settings for the surfaces on the scene - choose Combine by Postfixes in the Use LODs dropdown.UNIGINE 提供基于名称后缀的详细级别的自动分配和配置，使您能够在单个 FBX 文件中为模型的不同 LOD 创建和导出不同的网格。在命名这些网格时，您应该添加一个后缀来指定每个网格所代表的 LOD。您还可以在导入阶段为模型的每个 LOD 指定可见性和渐变距离，从而节省时间，因为您不必为场景中的表面调整这些设置：在 Use LODs 下拉列表中选择 Combine by Postfixes。

注意

See the video tutorial on how to configure LODs for more details.看视频教程如何配置 LOD更多细节。

You can also enable the Merge Static Meshes option for more optimization.您还可以启用Merge Static Meshes选项以进行更多优化。

1. The morph target import parameter that defines how the normals of the morph target are imported. Three modes are available:在 Use LODs 下拉列表中选择 Combine by Postfixes。

   

   This will show additional LODs settings:这将显示其他LOD设置：

   Max LODs Count	Number of Levels of Detail.Number of Levels of Detail.详细级别数。
   Postfix	Surface name postfix that determines the current LOD.确定当前LOD的表面名称后缀。
   Min Visibility	The minimum distance on which this LOD is visible in camera local axes.在摄像机局部轴上可见此LOD的最小距离。 -inf — the LOD is visible by default.-inf-默认情况下，LOD可见。
   Max Visibility	The maximum distance on which this LOD is visible in camera local axes.此 LOD 在相机局部轴中可见的最大距离。 inf — the LOD is visible by default.inf — LOD 默认可见。
   Min Fade	Over this distance, the surface fades in until it is completely visible. Along this distance the engine automatically interpolates the level of detail from completely invisible to completely opaque. Fading-in starts when the camera has reached the minimum distance of surface visibility and is in the full visibility range.在这个距离上，表面逐渐消失，直到完全可见。沿着这个距离，引擎会自动将细节级别从完全不可见插入到完全不透明。当相机达到表面能见度的最小距离并且处于完整的能见度范围内时，淡入开始。
   Max Fade	Over this distance, the surface fades out until it is completely invisible. Fading out starts when the camera has reached the maximum distance of surface visibility and is out of the full visibility range.在这个距离上，表面逐渐消失，直到完全不可见。当相机达到表面能见度的最大距离并且超出整个能见度范围时，就会开始淡出。

2. Select the number of LODs that are stored in the FBX container.选择存储在FBX容器中的LOD数量。

3. For each LOD, define a postfix that will be used to group objects in an FBX file into a corresponding LOD.对于每个LOD，定义一个后缀，该后缀将用于将FBX文件中的对象分组为相应的LOD。

   注意

   The postfix must be the same as the one used when creating objects in a 3D editor.后缀必须与在3D编辑器中创建对象时使用的后缀相同。

   The names of generated surfaces will be as follows: material_name + LOD_postfix.生成的曲面的名称如下：material_name + LOD_postfix。

4. Specify the minimum and maximum visibility and fade distances for each LOD.指定每个LOD的最小可见距离。每个LOD的最大可见距离等于下一个LOD的最小可见距离。最后一个LOD的最大可见距离等于inf。

Automatic Generation of LODs自动生成 LOD#

Automatic LOD Generation feature based on the meshoptimizer library will help in case you only have a high-poly model, saving you a lot of time on preparing levels of detail manually.自动 LOD 生成功能基于meshoptimizer 库将在您只有一个高多边形模型的情况下提供帮助，从而为您节省大量手动准备细节级别的时间。

To use the feature choose Auto-Generated in the Use LODs dropdown and configure the settings listed below - the Engine will do the rest, generating all LODs automatically based on your configuration.要使用该功能，请在 Use LODs 下拉列表中选择 Auto-Generated 并配置下面列出的设置 - 引擎将完成剩下的工作，并根据您的配置自动生成所有 LOD。

Max LODs Count	Number of Levels of Detail.Number of Levels of Detail.详细级别数。
Target Polycount	Desired degree of geometry simplification for each LOD (target geometry complexity percentage from the initial number of polygons).每个 LOD 所需的几何简化程度(目标几何复杂度与初始多边形数量的百分比)。 注意 Please keep in mind that this is only a target value, that in some cases may be unreachable for the mesh simplifier. In case any artefacts with the topology of the simplified meshes occur, try increasing this value.请记住，这只是一个目标值，在某些情况下，网格简化器可能无法达到。如果出现任何具有简化网格拓扑的伪影，请尝试增加此值。
Normals Preserve	This parameter indicates the impact of normals on mesh topology simplification. Higher values increase the influence of normals, by the value of 0 normals are ignored. Avoid setting too high values as this may restrict simplifier too much and simplification will fail (as normals may differ significantly). Default setting is suitable for most cases.该参数表示法线对网格拓扑简化的影响。较高的值会增加法线的影响，0 的值会忽略法线。避免设置太高的值，因为这可能会过多地限制简化器并且简化将失败（因为法线可能会有很大差异）。默认设置适用于大多数情况。
Recalculate Normals by Angle	Enables recalculation of normals in the process of mesh simplification based on the specified angle threshold. If an angle between the normals to adjacent polygons exceeds this value, normals will be recalculated between them to smoothen the look of the geometry and get rid of possible shading issues.启用基于指定角度阈值的网格简化过程中的法线重新计算。如果相邻多边形的法线之间的角度超过此值，则将在它们之间重新计算法线以平滑几何体的外观并消除可能的阴影问题。
Visibility / Fade Distances	See their description above.请参阅上面的描述。

This auxiliary section is available in the Parameters window when selecting an imported FBX asset in the Asset Browser. It enables you to preview the content of the FBX asset according to the current Mesh Import Options.在资源浏览器中选择导入的FBX资源时，该辅助部分可在Parameters窗口中使用。它使您可以根据当前预览FBX资源的内容。网格导入选项。

Nodes	List of nodes obtained from the FBX asset.从FBX资源获得的节点列表。
Surfaces	List of surfaces of the selected node.所选节点的曲面列表。
Use Custom Settings	Enables custom Lightmaps options for the selected surface(s).启用自定义光照贴图选定表面的选项。

The most commonly used type of data stored in an FBX container is polygonal geometry.FBX容器中存储的最常用数据类型是多边形几何。

When importing geometry keep in mind the following mesh limitations set in UNIGINE:在导入几何图形时，请记住以下在UNIGINE中设置的网格限制:

Maximum number of vertices per mesh每个网格的最大顶点数	4294967295
Maximum number of surfaces per mesh每目最大表面数	32768
Maximum amount of weights per vertex每个顶点的最大权重数	4
Maximum amount of bones per surface每个表面的最大骨数	128
Maximum number of active morph targets per surface每个表面的最大活动的变形目标数	7 for DX11 and OpenGL; unlimited for DX12 and Vulkan (100 is set by default)7为DX11和OpenGL；DX12和Vulkan无限制(100是默认设置)

To import 3D geometry data contained in an FBX scene, you should enable the Import Meshes option.要导入FBX场景中包含的3D几何数据，应启用Import Meshes选项。

Imported geometry (same as any object in the scene) after being added to the world, becomes a node and can be seen in the World Hierarchy window. This node will have the same name as the imported FBX asset and a hierarchy of child nodes representing the hierarchy of static meshes contained in the imported scene. 导入的几何图形（与场景中的任何对象相同）在添加到世界后变为节点并可以在World Hierarchy窗口中看到。该节点的名称与导入的FBX资源的名称相同，子节点的层次结构表示包含在导入场景中的静态网格物体的层次结构。

You can combine all child objects into a single one by enabling the Merge Static Meshes option. In this case, all surfaces of child meshes will be copied to the single parent mesh and will appear in its Surfaces hierarchy.您可以通过启用Merge Static Meshes选项将所有子对象合并为一个。在这种情况下，子网格物体的所有表面将被复制到单个父网格物体，并将出现在其Surfaces层次结构中。

Surfaces of a single mesh generated instead of separate meshes with device_calculator and glass_mat materials assigned生成单个网格的表面，而不是分配了device_calculator和glass_mat材质的单独网格

You can also merge the surfaces having the same material assigned by enabling the Merge Surfaces by Materials option.您也可以通过启用Merge Surfaces by Materials选项合并具有相同材质的曲面。

Surfaces merged by materials材质合并的表面

Different measurement systems can be used in different 3D modelling applications. To adjust the scale of imported geometry, you can use the Scale parameter.可以在不同的3D建模应用程序中使用不同的测量系统。要调整导入几何的比例，可以使用Scale参数。

It is also possible to optimize the vertex cache when importing geometry. To do so, use the Optimize Vertex Cache option.导入几何体时也可以优化顶点缓存。为此，请使用Optimize Vertex Cache选项。

The Import Tangent Space option allows importing built-in tangent space data instead of recalculating it.Import Tangent Space选项允许导入内置切线空间数据，而无需重新计算。

An FBX container can also store materials assigned to the surfaces of the objects in a 3D editor.FBX容器还可以在3D编辑器中存储分配给对象表面的材质。

To import materials from an FBX container, you should enable the Import Materials option. In this case, the surfaces of the imported model will have the corresponding materials assigned.要从FBX容器导入材质，应启用Import Materials选项。在这种情况下，将为导入的模型的曲面分配相应的材质。

注意

If materials are imported, the material assets are created in the materials subfolder of the folder where the .fbx asset is stored.如果材质是进口的，则该材质资源在存储.fbx资源的文件夹的materials子文件夹中创建。

The following textures will be imported and assigned (if any):以下纹理将被导入和分配（如果有）：

• Diffuse (albedo) texture
• Normal map or bump map (needs to be converted into 2-channel (RG) for Unigine)
• Specular texture
• Light map

The following material parameters will also be imported (if defined):还将导入以下材质参数（如果已定义）：

• Diffuse color
• Specular color and power
• Emission color

注意

You should adjust other material settings manually.你应该调整其他材质设置手动。

When the Import Materials option is disabled, all surfaces of the model will have the default mesh_base material assigned. 禁用Import Materials选项时，将为模型的所有曲面分配默认的mesh_base材质。

When importing materials, you might have a situation when a material with a given name already exists in the project. You can choose whether to overwrite existing materials (the corresponding assets will be overwritten) or not. For this purpose, the Overwrite Existing Materials option is used. When unchecked, existing materials will be used.导入材质时，项目中可能已经存在具有给定名称的材质。您可以选择是否覆盖现有材质（对应的资源将被覆盖）。为此，使用了Overwrite Existing Materials选项。如果未选中，则将使用现有材质。

In case when a source model contains lots of objects with many identical materials that just have different names (often happens when an FBX file was exported from a CAD system), it makes sense to combine such materials into a single one. To do so, you should enable the Merge Similar Materials option.如果源模型包含许多具有许多相同材质但名称不同的对象（通常是从FBX文件中导出FBX文件时发生的）电脑辅助设计系统），将这些材质合并为一个材质是有意义的。为此，您应该启用Merge Similar Materials选项。

UNIGINE支持两种PBR材质工作流程：Metalness和Specular。使用Workflow选项设置所需的工作流程。

When reading the materials data, you are also able to import textures stored in an FBX container. To do so, enable the Import Textures option.读取材质数据时，您还可以导入存储在FBX容器中的纹理。为此，启用Import Textures选项。

注意

If textures are imported, the corresponding texture assets are created in the same folder, where the .fbx asset is stored.如果导入纹理，则对应的纹理资源在存储.fbx资源的同一文件夹中创建。

You can import skeletal animations and morph targets from an FBX file.您可以从FBX文件导入骨骼动画和变形目标。

To import animations from an FBX container:要从FBX容器导入动画，请执行以下操作：

• Enable the Import Animations option.启用Import Animations选项。
• Specify the number of frames per second for imported animation in the Animation FPS field.在Animation FPS字段中为导入的动画指定每秒的帧数。

To import morph targets just enable the Import Morph Targets option. Morph targets will be imported as child nodes.要导入变形目标，只需启用Import Morph Targets选项。变形目标将作为子节点导入。

If you have an FBX file containing skeletal animation without any geometry, you can import it to your UNIGINE project via the Import Bones Without Skin and use generated .anim files.如果您有一个FBX文件，其中包含没有任何几何图形的骨骼动画，则可以通过Import Bones Without Skin将其导入到UNIGINE项目中，并使用生成的.anim文件。

You can import light sources from an FBX scene (if any) by simply enabling the Import Lights option. Imported light sources will be added as child nodes to the root node. The following conversion will be performed:您可以通过简单地启用Import Lights选项从FBX场景导入光源（如果有）。导入的光源将作为子节点添加到根节点。将执行以下转换：

• Directional lights are converted into world light sources.定向光将转换为world光源。
• Point lights are converted into omni light sources.点光源将转换为omni光源。
• Spot lights are converted into projected light sources.聚光灯转换为projected光源。

The following parameters of lights are automatically imported into UNIGINE, so there is no need to set them up twice:以下灯光参数会自动导入到UNIGINE中，因此无需将它们设置两次：

• Light color浅色
• Light radius and attenuation光半径和衰减
• Light source position and orientation光源位置和方向

Cameras can also be imported from an FBX scene (if they exist) by simply enabling the Import Cameras option. They are converted into PlayerDummy (cameras without physical properties). Both types of projection are supported in UNIGINE:只需启用Import Cameras选项，也可以从FBX场景导入摄像机（如果存在）。它们被转换为PlayerDummy（没有物理属性的相机）。 UNIGINE支持两种类型的投影：

• Orthographic (with Z near and far clipping planes support)正交（具有Z远近裁剪平面支持）
• Perspective (with FOV support)透视图（在FOV支持下）

To view the scene through the imported camera choose its name in the drop-down list in the top left corner of the Editor Viewport window.要通过导入的摄像机查看场景，请在Editor Viewport窗口左上角的下拉列表中选择其名称。