Add: [AssimpImport], [AssimpExport]

[banidu-512]

Operators for importing and exporting 3D model files using the Assimp library (via AssimpNetter).

AssimpImport

The ultimate simple 3D model loader supporting 40+ file formats including OBJ, FBX, GLTF, GLB, STL, PLY, COLLADA, 3DS, BLEND, and more.

Inputs

Name	Type	Default	Description
FilePath	string	""	Path to 3D model file
PostProcessFlags	enum	Basic	Preprocessing preset: None, Basic, Full
Scale	float	1.0	Uniform scale multiplier
Normalize	bool	true	Normalize model to fit in unit cube
AxisConversion	enum	None	Axis conversion mode
FlipNormals	bool	false	Flip all vertex normals
SelectedMeshIndex	int	-1	Load specific mesh (-1 for all)

PostProcessFlags Options

• None - Raw mesh data, no processing
• Basic - Triangulate + generate smooth normals (default)
• Full - All optimizations: triangulation, smooth normals, UV generation, tangent space calculation, vertex joining, material cleanup, cache locality optimization

AxisConversion Options

• None - No transformation
• YUpToZUp - Convert Y-up coordinate system to Z-up
• ZUpToYUp - Convert Z-up coordinate system to Y-up
• FlipX - Mirror across X axis
• FlipY - Mirror across Y axis
• FlipZ - Mirror across Z axis

Outputs

Name	Type	Description
MeshData	MeshBuffers	GPU buffers for mesh rendering (vertices + indices)
Points	BufferWithViews	Points at each vertex position
Metadata	string	Human-readable info (vertices, faces, bounds, etc.)
VertexCount	int	Total vertex count
FaceCount	int	Total face/triangle count
MeshCount	int	Number of meshes in file
BoundsMin	Vector3	Bounding box minimum corner
BoundsMax	Vector3	Bounding box maximum corner
MeshNames	string	Pipe-delimited list of mesh names
SkeletonBuffers	SkeletonBuffers	Bone buffers, skin weight buffers, and animation metadata
BoneCount	int	Number of bones in skeleton
AnimationCount	int	Number of animation clips
AnimationNames	string	Pipe-delimited list of animation names

Features

• Multi-mesh support - Load all meshes from a file or select a specific one by index
• Automatic tangent calculation - Computes proper tangent space for normal mapping with degenerate UV handling
• Vertex color support - Stores first color channel in Selection field
• Metadata output - Get statistics about loaded models
• Resource caching - Efficient file loading with automatic caching
• Parameter change detection - PostProcessFlags changes trigger automatic reload
• Proper normalization - Normals are renormalized after scaling/normalization
• Animation support - Extract bone hierarchy, skin weights, and animation clip metadata
• Skeletal animation buffers - GPU buffers for bones (bind/offset matrices) and vertex skin weights (up to 4 influences per vertex)

AssimpExport

Export mesh or point cloud data to various 3D file formats with automatic counter-based naming.

Inputs

Name	Type	Default	Description
MeshData	MeshBuffers	null	GPU mesh buffers to export
Points	BufferWithViews	null	Points to export (alternative to mesh)
FolderPath	string	"exports"	Output folder path (files auto-named)
ExportMesh	bool	trigger	Trigger button to export mesh data
ExportPoints	bool	trigger	Trigger button to export point data
ExportFormat	enum	Auto	Format preset (determines file extension)
MeshName	string	"mesh"	Base name for exported files
ResetCounter	bool	trigger	Reset export counter to 1
MaxVertexCount	int	0	Maximum vertices/points to export (0 = no limit)
CustomFormat	string	""	Custom format ID (when ExportFormat is Custom)
GltfOptions	enum	Default	glTF/GLB export options (reserved)

ExportFormat Options

• Auto - Default to FBX format
• Obj - Wavefront OBJ (.obj)
• Fbx - Autodesk FBX (.fbx)
• Gltf - glTF 2.0 JSON (.gltf)
• Glb - glTF 2.0 Binary (.glb)
• Stl - STL for 3D printing (.stl)
• Ply - Stanford PLY (.ply)
• Collada - COLLADA (.dae)
• ThreeDs - 3D Studio (.3ds)
• Custom - Use custom format ID

Outputs

Name	Type	Description
Success	bool	True if export succeeded
StatusMessage	string	Export result: filename or error message

Features

• Automatic counter-based naming - Files are named MeshName_001.ext, MeshName_002.ext, etc.
• Folder-based output - Specify a folder; filenames are generated automatically
• Dual export triggers - Separate buttons for mesh and point cloud export
• Counter reset - Reset the counter to start a new export sequence
• Vertex/Point limiter - Set MaxVertexCount > 0 to limit exported vertices/points (0 = no limit)
• Wide format support - Export to 20+ formats (FBX, glTF, OBJ, STL, PLY, COLLADA, 3DS, etc.)
• Complete data export - Includes tangents, bitangents, and vertex colors when present
• Automatic directory creation - Creates output directories if they don't exist
• Filename sanitization - Invalid characters in MeshName are automatically replaced with underscores

Usage Examples

Basic mesh export

CubeMesh → AssimpExport (FolderPath: "exports", MeshName: "cube", ExportFormat: Fbx, ExportMesh: trigger)
→ Creates: exports/cube_001.fbx, cube_002.fbx, etc.

Export to glTF

Model → AssimpExport (FolderPath: "C:/Models/glTF", MeshName: "character", ExportFormat: Glb, ExportMesh: trigger)
→ Creates: C:/Models/glTF/character_001.glb

Export point cloud

PointCloud → AssimpExport (FolderPath: "pointclouds", ExportFormat: Ply, ExportPoints: trigger)
→ Creates: pointclouds/mesh_001.ply

Reset counter and start new sequence

Counter → IntDisplay
AssimpExport (ResetCounter: trigger) → Counter resets to 1

Export loop (exporting frames)

Time (0..1) → AssimpExport (ExportMesh: triggered each time)
→ Creates: mesh_001.fbx, mesh_002.fbx, ..., mesh_999.fbx

Technical Notes

• Uses AssimpNetter v6.0.2.1 (Assimp 6.x)
• Import uses Resource caching pattern for efficient file loading
• Export reads back GPU buffers using staging resources
• Proper disposal of GPU resources implemented
• Tangent space calculation uses the Lengyel algorithm with degenerate UV protection
• Automatic triangulation of quads and n-gons
• Smoothing groups converted to vertex normals
• PostProcessFlags changes trigger automatic reload via cache invalidation
• Normals are renormalized after scaling/normalization to maintain unit length
• Export includes tangents, bitangents, and vertex colors when available
• Output directories are created automatically if needed
• Filename sanitization removes invalid characters (<>:"/\|?*) and limits length to 100 characters

Supported Formats

Import Formats (40+)

3DS, 3D, AC, AC3D, ACC, AMJ, ASE, ASK, B3D, BLEND, BVH, COB, DXF, ENFF, FBX, GLTF, GLB, IRR, IRRMESH, LWO, LWS, LXO, MD2, MD3, MD5, MDC, MDL, NFF, NDO, OBJ, OFF, OGEX, PLY, MS3D, LWO, RRM, Q3D, Q3BSP, RAW, SIB, SMD, STP, STL, TERRAGEN, 3D, X, X3D, XGL, ZGL

Export Formats (20+)

3DS, ASE, ASSBIN, ASSXML, BVH, COLLADA, DXF, FBX, GLB, GLTF, M3D, OBJ, PLY, PMD, PMX, STEP, STL, TER, X, X3D, XGL