Reconstruct3D - 3D Reconstruction

Overview

The Reconstruct3D interface is used to generate 2D and 3D models from aerial triangulation results. It is typically used with ReconstructAT to complete the full reconstruction workflow. This interface supports multiple output formats, block processing, and fine-grained parameter control.

Applicable Scenarios

• Generate 3D models from aerial triangulation results
• Generate orthophotos and digital surface models
• Block reconstruction for large-scale data
• Need specific output formats

Interface Usage

Command Line Usage

reconstruct_full_engine.exe -reconstruct_type 2 -task_json 3d_config.json

Parameter Description

• reconstruct_type: Fixed as 2 (indicates Reconstruct3D)
• task_json: Configuration file path

Configuration Parameters

Required Parameters

Parameter	Type	Description
license_id	int	SDK license code, unified as 9200
working_dir	string	Working directory (must be same as aerial triangulation)
gdal_folder	string	GDAL data path
input_image_type	int	Image type: 1=RGB, 2=Multispectral, 3=Infrared
image_meta_data	JSON Array	Input image metadata information
resolution_level	int	Reconstruction accuracy: 1=High accuracy, 2=Medium accuracy, 3=Low accuracy

Optional Parameters

Basic Parameters

Parameter	Type	Default	Description
reconstruct_mode	int	0	Reconstruction mode: 0=General scene, 1=Surrounding scene, 2=Power line scene
min_avali_memory_size	double	0	Minimum available memory (GB), used to control block quantity
fast_mode	bool	false	Fast mode, improves efficiency but reduces detail
keep_undistort_images	bool	false	Whether to keep undistorted images

Output Format Control

Parameter	Type	Default	Description
generate_osgb	bool	false	Generate OSGB format 3D model
generate_3d_tiles	bool	false	Generate 3D Tiles (b3dm) format
generate_las	bool	false	Generate LAS format point cloud
generate_pc_ply	bool	false	Generate PLY format point cloud
generate_pc_osgb	bool	false	Generate OSGB format point cloud LOD
generate_pc_pnts	bool	false	Generate pnts format point cloud LOD
generate_obj	bool	false	Generate OBJ format textured mesh
generate_ply	bool	false	Generate PLY format textured mesh
generate_geotiff	bool	false	Generate GeoTIFF format orthophoto
generate_tile_2D	bool	false	Perform tile cutting on orthophoto
generate_2D_from_3D_model	bool	false	Generate 2D orthophoto from 3D model

Advanced Parameters

Parameter	Type	Default	Description
use_draco_compression	bool	true	Whether to use Draco compression for 3D Tiles
tex_image_type_3dtiles	int	0	3D Tiles texture format: 0=JPEG, 1=WebP
use_gcj02	bool	false	Whether to convert orthophoto tiles to GCJ02 coordinate system
coordinate_system_3d	JSON	-	Coordinate system for 3D output
coordinate_system_2d	JSON	-	Coordinate system for 2D output
roi_for_2d	JSON	-	Region of interest for 2D reconstruction
roi_for_3d	JSON	-	Region of interest for 3D reconstruction
roi_coordinate_system	JSON	WGS84	Coordinate system for ROI

Data Structure Description

Camera Metadata

{
  "id": 1,                     // Unique camera ID
  "meta_data": {
    "camera_name": "Camera-1",    // Camera name
    "projection_model": 0,       // Projection model (optional)
    "width": 4000,              // Sensor width (pixels)
    "height": 3000,             // Sensor height (pixels)
    "parameters": [             // Camera intrinsics (10 elements array)
      // fx, fy, cx, cy, k1, k2, p1, p2, k3，placeholder_param
    ]
  }
}

ROI (Region of Interest)

{
  "boundary": [              // 2D polygon boundary (counter-clockwise)
    [x1, y1],
    [x2, y2],
    [x3, y3]
    // ...
  ],
  "min_z": 100.0,           // Minimum elevation (optional)
  "max_z": 500.0            // Maximum elevation (optional)
}

Output Coordinate System Settings

{
  "coordinate_system_3d": {
    "type": 3,              // Projected coordinate system
    "epsg_code": 32650      // UTM Zone 50N
  },
  "coordinate_system_2d": {
    "type": 2,              // Geographic coordinate system
    "epsg_code": 4326       // WGS84
  }
}

Complete Configuration Examples

Basic 3D Reconstruction

{
  "license_id": 9200,
  "working_dir": "C:/Projects/3D_Task",
  "gdal_folder": "C:/MipMap/SDK/data",
  "input_image_type": 1,
  "resolution_level": 2,
  "image_meta_data": [
    {
      "id": 1,
      "path": "C:/Images/DJI_0001.JPG"
    },
    {
      "id": 2,
      "path": "C:/Images/DJI_0002.JPG"
    }
  ],
  "generate_osgb": true,
  "generate_3d_tiles": true,
  "generate_las": true,
  "generate_geotiff": true
}

High-precision Reconstruction Configuration

{
  "license_id": 9200,
  "working_dir": "C:/Projects/HighQuality_3D",
  "gdal_folder": "C:/MipMap/SDK/data",
  "input_image_type": 1,
  "resolution_level": 1,      // Highest accuracy
  "reconstruct_mode": 0,      // General scene
  "image_meta_data": [...],
  "generate_osgb": true,
  "generate_3d_tiles": true,
  "generate_obj": true,
  "generate_geotiff": true,
  "generate_tile_2D": true,
  "coordinate_system_3d": {
    "type": 3,
    "epsg_code": 32650        // UTM 50N
  },
  "coordinate_system_2d": {
    "type": 2,
    "epsg_code": 4326         // WGS84
  }
}

Large-scale Data Block Reconstruction

{
  "license_id": 9200,
  "working_dir": "C:/Projects/LargeScale_3D",
  "gdal_folder": "C:/MipMap/SDK/data",
  "input_image_type": 1,
  "resolution_level": 2,
  "min_avali_memory_size": 16.0,  // Limit each block to maximum 16GB memory
  "image_meta_data": [...],
  "roi_for_3d": {
    "boundary": [
      [114.12, 22.12],
      [114.13, 22.12],
      [114.13, 22.13],
      [114.12, 22.13]
    ],
    "min_z": 0,
    "max_z": 500
  },
  "generate_3d_tiles": true,
  "use_draco_compression": true,
  "tex_image_type_3dtiles": 1    // Use WebP texture compression
}

Special Scene Configuration

Surrounding Object Reconstruction

{
  "license_id": 9200,
  "working_dir": "C:/Projects/Object_3D",
  "gdal_folder": "C:/MipMap/SDK/data",
  "input_image_type": 1,
  "resolution_level": 1,
  "reconstruct_mode": 1,      // Surrounding scene mode
  "image_meta_data": [...],
  "generate_obj": true,
  "generate_ply": true,
  "coordinate_system_3d": {
    "type": 1               // Local coordinate system
  }
}

Generate Orthophoto Only

{
  "license_id": 9200,
  "working_dir": "C:/Projects/Ortho_Only",
  "gdal_folder": "C:/MipMap/SDK/data",
  "input_image_type": 1,
  "resolution_level": 2,
  "image_meta_data": [...],
  "generate_geotiff": true,
  "generate_tile_2D": true,
  "generate_2D_from_3D_model": true,
  "roi_for_2d": {
    "boundary": [...]       // Specify orthophoto extent
  },
  "coordinate_system_2d": {
    "type": 3,
    "epsg_code": 32650
  }
}

Output Results

3D Model Output (products/3D/)

• model-osgb/ - OSGB format model and LOD
• model-b3dm/ - 3D Tiles format (with tileset.json)
• model-obj/ - OBJ format model and textures
• point-las/ - LAS format point cloud
• point-ply/ - PLY format point cloud
• point-osgb/ - OSGB format point cloud LOD
• point-pnts/ - 3D Tiles point cloud format

2D Product Output (products/2D/)

• geotiffs/ - GeoTIFF format orthophoto and DSM
• dom_tiles/ - Orthophoto tiles
• dsm_tiles/ - Digital surface model tiles

Intermediate Results (milestones/)

• undistorted/ - Undistorted images (if kept)
• depth_maps/ - Depth maps
• mesh/ - Intermediate mesh data

Resolution Level Description

Level	Description	Relative Processing Time	Application Scenarios
1	Ultra-high accuracy	3-5x	Professional surveying, cultural heritage protection
2	High accuracy	1x	General engineering applications
3	Quick preview	0.2-0.3x	Quick validation, preview

Balance Between Accuracy and Efficiency

• resolution_level=1: Highest geometric detail and texture clarity
• resolution_level=2: Balance quality and efficiency, recommended for most applications
• resolution_level=3: Fast processing, suitable for preliminary validation

Best Practices

1. Memory Management

For large-scale data:

{
  "min_avali_memory_size": 24.0,  // Set based on available memory
  "resolution_level": 2            // Consider reducing accuracy
}

2. Output Format Selection

• Web Display: Use 3D Tiles + Draco compression
• GIS Analysis: Generate GeoTIFF and LAS
• Professional Software: Use OSGB format
• Editing and Processing: Export OBJ or PLY

3. Coordinate System Settings

• 3D models typically use projected coordinate systems (e.g., UTM)
• Orthophotos can use geographic or projected systems based on needs
• Consider using WGS84 for web applications

4. ROI Usage

• Use ROI generated from aerial triangulation as base
• Adjust range according to needs
• Set separate ROIs for 2D and 3D

Performance Optimization

Fast Processing

{
  "resolution_level": 3,
  "fast_mode": true,
  "generate_3d_tiles": true,  // Generate only necessary formats
  "use_draco_compression": true
}

High-quality Output

{
  "resolution_level": 1,
  "fast_mode": false,
  "keep_undistort_images": true,  // Keep intermediate results for inspection
  "generate_obj": true,            // Generate high-quality mesh
  "generate_geotiff": true
}

Common Questions

Q: Error "Cannot find aerial triangulation results"

A: Ensure:

• working_dir is the same as used in ReconstructAT
• Aerial triangulation completed successfully
• milestones directory contains mvs.xml file

Q: Out of memory error

A:

• Set min_avali_memory_size to limit memory usage
• Reduce resolution_level
• Use DivideTiles for pre-blocking

Q: Incorrect output coordinates

A:

• Check coordinate_system_3d/2d settings
• Confirm ROI coordinate system matches data
• Verify GDAL data path is correct

Next Steps

• Check Output Format Details
• Learn about Block Processing for large-scale data
• Study Basic Concepts to optimize reconstruction quality

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Note: Reconstruct3D provides rich output options. It's recommended to first validate with low accuracy, then proceed with high-quality reconstruction.