建模 — UV
前置条件：先阅读 unreal-modeling。
库
CDO：/Script/GeometryScriptingCore.Default__GeometryScriptLibrary_MeshUVFunctions
TargetMesh 为 UDynamicMesh* 路径字符串。UVSetIndex（别名 UVChannel）为 int，通常 0。Debug 省略。需要 FGeometryScriptMeshSelection 的函数，用 MeshOperationLibrary 桥接（见 unreal-modeling）。
主要函数
UV 通道管理
| 函数 | 关键参数 | 说明 | |
|---|
SetNumUVSets | TargetMesh, NumUVSets | 设置 UV 通道数量 | |
ClearUVChannel | TargetMesh, UVChannel | 清空指定 UV 通道 | |
CopyUVSet | TargetMesh, FromUVSet, ToUVSet | 复制 UV 通道 | |
UV 自动生成
| 函数 | 关键参数 | 说明 | |
|---|
AutoGenerateXAtlasMeshUVs | TargetMesh, UVSetIndex, Options | XAtlas 自动展开（推荐通用方案） | |
AutoGeneratePatchBuilderMeshUVs | TargetMesh, UVSetIndex, Options | PatchBuilder 自动展开（更多控制） | |
RecomputeMeshUVs | TargetMesh, UVSetIndex, Options, Selection | 基于已有岛或 Polygroup 重新计算 UV | |
UV 投影
| 函数 | 关键参数 | 说明 | |
|---|
SetMeshUVsFromPlanarProjection | TargetMesh, UVSetIndex, PlaneTransform, Selection | 平面投影。PlaneTransform 的 Scale 定义映射到 1 UV 的世界尺寸 | |
SetMeshUVsFromBoxProjection | TargetMesh, UVSetIndex, BoxTransform, Selection, MinIslandTriCount | 盒体投影 | |
SetMeshUVsFromCylinderProjection | TargetMesh, UVSetIndex, CylinderTransform, Selection, SplitAngle | 圆柱投影 | |
UV 布局与打包
| 函数 | 关键参数 | 说明 | |
|---|
RepackMeshUVs | TargetMesh, UVSetIndex, RepackOptions | 重新打包 UV 岛 | |
LayoutMeshUVs | TargetMesh, UVSetIndex, LayoutOptions, Selection | 布局 UV（支持多种模式） | |
ApplyTexelDensityUVScaling | TargetMesh, UVSetIndex, Options, Selection | 按纹素密度缩放 UV | |
UV 变换
| 函数 | 关键参数 | 说明 | |
|---|
TranslateMeshUVs | TargetMesh, UVSetIndex, Translation, Selection | 平移 UV | |
ScaleMeshUVs | TargetMesh, UVSetIndex, Scale, ScaleOrigin, Selection | 缩放 UV | |
RotateMeshUVs | TargetMesh, UVSetIndex, RotationAngle, RotationOrigin, Selection | 旋转 UV（角度制） | |
UV 查询
| 函数 | 关键参数 | 说明 | |
|---|
GetMeshUVSizeInfo | TargetMesh, UVSetIndex, Selection | 返回 3D 面积、UV 面积、3D 包围盒、UV 包围盒等 | |
GetMeshPerVertexUVs | TargetMesh, UVSetIndex | 获取每顶点 UV 列表 | |
UV 传输
| 函数 | 关键参数 | 说明 | |
|---|
TransferMeshUVsByProjection | TargetMesh, TargetUVChannel, TargetSelection, TargetTransform, SourceMesh, SourceMeshOptionalBVH, SourceUVChannel, SourceSelection, SourceTransform, Settings, ProjectionDirection | 通过投影从源 mesh 传输 UV | |
SetUVSeamsAlongSelectedEdges | TargetMesh, UVChannel, Selection, bInsertSeams | 沿选中边设置/移除 UV 接缝 | |
UV 底层操作
| 函数 | 关键参数 | 说明 | |
|---|
SetMeshTriangleUVs | TargetMesh, UVSetIndex, TriangleID, UVs | 设置单个三角形的 UV | |
AddUVElementToMesh | TargetMesh, UVSetIndex, NewUVPosition | 添加 UV 元素 | |
SetMeshUVElementPosition | TargetMesh, UVSetIndex, ElementID, NewUVPosition | 设置 UV 元素位置 | |
CopyMeshUVLayerToMesh | CopyFromMesh, UVSetIndex, CopyToUVMesh | 将 UV 通道导出为独立 mesh | |
CopyMeshToMeshUVLayer | CopyFromUVMesh, ToUVSetIndex, CopyToMesh | 将 mesh 写回 UV 通道 | |
结构体与枚举
FGeometryScriptRecomputeUVsOptions
| 字段 | 类型 | 默认值 | 说明 | |
|---|
Method | EGeometryScriptUVFlattenMethod | SpectralConformal | 展平算法 | |
IslandSource | EGeometryScriptUVIslandSource | UVIslands | 岛来源 | |
ExpMapOptions | struct | — | ExpMap 专用选项 | |
SpectralConformalOptions | struct | — | SpectralConformal 专用选项 | |
GroupLayer | FGeometryScriptGroupLayer | 默认层 | Polygroup 层（当 IslandSource=PolyGroups 时） | |
bAutoAlignIslandsWithAxes | bool | true | 自动对齐岛到坐标轴 | |
EGeometryScriptUVFlattenMethod
| 值 | 说明 | |
|---|
ExpMap | 指数映射 | |
Conformal | 保角映射 | |
SpectralConformal | 谱保角映射（推荐） | |
EGeometryScriptUVIslandSource
| 值 | 说明 | |
|---|
PolyGroups | 按 Polygroup 分岛 | |
UVIslands | 按已有 UV 岛分岛 | |
FGeometryScriptXAtlasOptions
FGeometryScriptPatchBuilderOptions
| 字段 | 类型 | 默认值 | 说明 | |
|---|
InitialPatchCount | int | 100 | 初始 patch 数量 | |
MinPatchSize | int | 2 | 最小 patch 大小 | |
PatchCurvatureAlignmentWeight | float | 1.0 | 曲率对齐权重 | |
PatchMergingMetricThresh | float | 1.5 | 合并度量阈值 | |
PatchMergingAngleThresh | float | 45.0 | 合并角度阈值 | |
bRespectInputGroups | bool | false | 尊重输入 Polygroup | |
bAutoPack | bool | true | 自动打包 | |
PackingOptions | FGeometryScriptRepackUVsOptions | — | 打包选项 | |
FGeometryScriptRepackUVsOptions
| 字段 | 类型 | 默认值 | |
|---|
TargetImageWidth | int | 512 | |
bOptimizeIslandRotation | bool | true | |
FGeometryScriptLayoutUVsOptions
| 字段 | 类型 | 默认值 | 说明 | |
|---|
LayoutType | EGeometryScriptUVLayoutType | Repack | 布局类型 | |
TextureResolution | int | 1024 | 纹理分辨率 | |
Scale | float | 1 | 打包后缩放 | |
Translation | FVector2D | (0,0) | 打包后平移 | |
bPreserveScale | bool | false | 保留岛缩放 | |
bPreserveRotation | bool | false | 保留岛旋转 | |
bAllowFlips | bool | false | 允许翻转 | |
EGeometryScriptUVLayoutType
| 值 | 说明 | |
|---|
Transform | 应用 Scale/Translation | |
Stack | 每个岛独立缩放到单位正方形 | |
Repack | 集体打包到单位正方形（无重叠） | |
Normalize | 归一化纹素密度 | |
JSON 示例
XAtlas 自动展开：
json
{"object":"/Script/GeometryScriptingCore.Default__GeometryScriptLibrary_MeshUVFunctions","function":"AutoGenerateXAtlasMeshUVs","params":{"TargetMesh":"/Engine/Transient.DynamicMesh_0","UVSetIndex":0,"Options":{"MaxIterations":2}}}
盒体投影：
json
{"object":"/Script/GeometryScriptingCore.Default__GeometryScriptLibrary_MeshUVFunctions","function":"SetMeshUVsFromBoxProjection","params":{"TargetMesh":"/Engine/Transient.DynamicMesh_0","UVSetIndex":0,"BoxTransform":{"Rotation":{"X":0,"Y":0,"Z":0,"W":1},"Translation":{"X":0,"Y":0,"Z":0},"Scale3D":{"X":100,"Y":100,"Z":100}},"Selection":{},"MinIslandTriCount":2}}
重新计算 UV（SpectralConformal）：
json
{"object":"/Script/GeometryScriptingCore.Default__GeometryScriptLibrary_MeshUVFunctions","function":"RecomputeMeshUVs","params":{"TargetMesh":"/Engine/Transient.DynamicMesh_0","UVSetIndex":0,"Options":{"Method":"SpectralConformal","IslandSource":"UVIslands","bAutoAlignIslandsWithAxes":true},"Selection":{}}}
发现
对 CDO 路径调用 DescribeObject 可查看完整函数列表和参数签名。