S-CIT

High-performance web-based 3D point cloud editor built with Bevy and Rust.

Features

• GPU-accelerated rendering of millions of points
• Unified RGBA32F texture pipeline for positions, colours, and classifications
• Real-time polygon classification with compute shaders
• Eye Distance Lighting (EDL) depth enhancement
• Spatial indexing with Z-order curve optimisation
• Cross-platform: native desktop and WebGPU web deployment

Prerequisites

Core Dependencies

# Install Rust
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

# Add WebAssembly target
rustup target add wasm32-unknown-unknown

# Install trunk for web builds
cargo install trunk

Frontend Dependencies

# Install Node.js 20+
# Download from https://nodejs.org/

# Install frontend dependencies
npm install

Pre-Build Generate Assets

Process Point Cloud Data

# Convert LAZ/LAS to unified texture format
cargo run --bin point-cloud-pre-processing <path to your input laz file>.laz <asset_dir> <output dir>
# For example the default expected asset location will be:
cargo run --bin point-cloud-pre-processing
/home/repository/point-cloud-render-engine/assets/riga_numbered_0.05.laz
/home/repository/point-cloud-render-engine/assets/placeable_assets
/home/repository/point-cloud-render-engine/assets/output

This generates:

• input_file_position_2048x2048.dds - RGBA32F: XYZ coordinates + connectivitcay class id (a unique id for instances of a classification)
• input_file_colour_class_2048x2048.dds - RGBA32F: RGB colour + classification
• input_file_spatial_index_2048x2048.dds - RGBA32F: Morton codes + spatial data
• input_file_heightmap_2048x2048.dds - R32F: Road surface elevation
• input_file_metadata_2048x2048.json - Bounds and processing statistics

Build Process

1. Build Post-Build Script

note: this script only needs to be compiled for your system once.

# From project root
rustc ./point-cloud-render-engine/scripts/html_config.rs -o ./point-cloud-render-engine/scripts/html_config.bin

2. Build Web Application

# Generate WASM and web assets (from project root)
trunk build --release

3. Start Frontend Server

# if you use NVM
nvm use 20

# Install dependencies (first time only)
npm install

# Start development server
npm run dev

Configuration details in constants crate

/// Generated Asset Details
pub const RELATIVE_MANIFEST_PATH: &'static str = "output/";
pub const TERRAIN_PATH: &'static str = "/terrain/";
pub const ASSET_PATH: &'static str = "/assets/AssetAtlas/";
pub const TEXTURE_RESOLUTION_FILE_PATH: &'static str = "2048x2048";

/// Road classification codes for heightmap generation
pub const ROAD_CLASSIFICATIONS: &[u8] = &[2, 10, 11, 12];

/// Coordinate transform for input LiDAR PC Coordinate System
pub const COORDINATE_TRANSFORM: [[f64; 3]; 3] = [
    [1.0, 0.0, 0.0],  // X = X
    [0.0, 0.0, 1.0],  // Y = Z
    [0.0, -1.0, 0.0], // Z = -Y
];

/// The maximum number of points the compute shader expects to perform re-classification and hide operations
pub const MAXIMUM_POLYGON_POINTS: usize = 2048;

/// The maximum number of polygons the compute shader expects to perform re-classification and hide operations
pub const MAXIMUM_POLYGONS: usize = 512;

/// The maximum number of polygons the compute shader expects to perform re-classification and hide operations
pub const MAX_IGNORE_MASK_LENGTH: usize = 512;


/// EDL lighting config
pub const DRAW_LINE_WIDTH: f32 = 0.076;
pub const MOUSE_RAYCAST_INTERSECTION_SPHERE_SIZE: f32 = 0.125;
pub const DRAW_VERTEX_SIZE: f32 = 0.08;

/// Texture DDS settings:
/// Unified texture resolution for all generated textures (positions, colour+class, heightmap)
pub const TEXTURE_SIZE: usize = 2048;

/// Maximum points that can fit in a texture
pub const MAX_POINTS: usize = TEXTURE_SIZE * TEXTURE_SIZE;

/// Heightmap blend radius for road surface smoothing (pixels)
pub const HEIGHTMAP_BLEND_RADIUS: f32 = 64.0;

/// Sample size for colour detection
pub const COLOUR_DETECTION_SAMPLE_SIZE: usize = 100;

Run Application

# Native desktop (Development environment only)
cargo run --bin point-cloud-render-engine

# Web (after trunk build)
npm run dev
# Navigate to http://localhost:<your_port>

Development Controls (no integration with the front end in the current release)

Camera Navigation

• Mouse Wheel: Zoom in/out
• Right Mouse + Drag: Free look
• WASD: Move around
• Q/E: Up and down
• R/F Pitch camera
• Hold + Shift: Move faster
• Hold + Ctrl: Move slower

Render Modes

• Z: RGB Colour (default)
• X: Original Classification
• C: Modified Classification
• V: Morton Code Debug
• B: Performance Debug
• N: Class Selection Mode

Technical Specifications

Texture Pipeline

• Resolution: 2048×2048 (configurable via TEXTURE_SIZE constant)
• Format: 32-bit float textures for precision
• Capacity: maximum number of points is determined by TEXTURE_SIZE: 1k -> 8k (~1 million -> ~67 million) points
• Coordinate Transform: -90° X rotation (Z→Y, -Y→Z, X→X)

Performance Features

• Spatial indexing using Z-order curves
• GPU compute shaders for classification modification tools
• Parallel processing with Rayon
• Eye Distance Lighting for depth perception

File Support

• Input: LAZ/LAS files with optional RGB data
• Output: DDS textures + JSON metadata

Platform Support

• Desktop: Windows, macOS, Linux (native performance)
• Web: Chrome, Firefox, Safari (Experimental WebGPU required)

Minimum Requirements

• GPU: WebGPU-compatible (DirectX 12, Vulkan, or Metal)
• RAM: 6GB recommended for large datasets
• Browser: Chrome 113+, Firefox 121+, Safari 17+ (for web deployment)