A Rust implementation of Eric Lengyel's Transvoxel Algorithm, which provides seamless stitching of voxel terrain meshes at differing resolutions (LOD — Level of Detail).

When generating triangle meshes from voxel data using Marching Cubes at multiple resolutions, cracks form along the boundaries between meshes of different resolutions. The Transvoxel Algorithm solves this by inserting special transition cells at the boundary between high-resolution and low-resolution voxel data.

Instead of handling ~1.2 million combinations, the algorithm considers only 9 samples of high-resolution data → 512 cases → 73 equivalence classes.

• Full Marching Cubes regular cell extraction
• Transition cell extraction for all 6 sides (LowX, HighX, LowY, HighY, LowZ, HighZ)
• Smooth vertex normal interpolation via central-difference gradients
• Density-field based surface extraction
• Configurable threshold value
• Zero external dependencies

use transvoxel::prelude::*;

// Define a density function (e.g., a sphere)
fn sphere(x: f32, y: f32, z: f32) -> f32 {
    5.0 - (x * x + y * y + z * z).sqrt()
}

fn main() {
    let block = Block::new([-6.0, -6.0, -6.0], 12.0, 16);
    let threshold = 0.0f32;
    let sides = TransitionSides::empty();

    let mesh = extract_mesh(&sphere, &block, threshold, sides);
    println!("Triangles: {}", mesh.triangle_count());
    println!("Vertices:  {}", mesh.vertex_count());
}

cargo run --bin demo

cargo test

• transvoxel.org — Eric Lengyel's official page
• Lengyel, Eric. "Voxel-Based Terrain for Real-Time Virtual Simulations". PhD diss., University of California at Davis, 2010.
• Lengyel, Eric. "Transition Cells for Dynamic Multiresolution Marching Cubes". Journal of Graphics, GPU, and Game Tools. Vol. 15, No. 2 (2010).

MIT