Extensions

The 3MF specification is modular, with a core specification and optional extensions that add specialized capabilities. lib3mf-rs implements all 9 official extensions with 100% feature coverage.

What are 3MF Extensions?

Extensions are additions to the core 3MF specification that enable advanced manufacturing scenarios. They use XML namespaces to add new elements and attributes without breaking compatibility.

A 3MF file can use multiple extensions simultaneously. For example, a file might combine Materials (colors/textures), Production (part tracking), and Slice (pre-sliced layers) extensions.

Supported Extensions

Total: 336/345 features (97.4%)

Extension Details

Materials and Properties Extension (v1.2.1)

Purpose: Add color, texture, and advanced material properties to geometry.

Features:

• Base Materials — Solid colors (RGB/RGBA) with display names
• Color Groups — Per-vertex color gradients via color property groups
• Texture 2D — UV-mapped images with tile styles and filtering
• Composite Materials — Blend multiple materials with mixing ratios
• Multi-Properties — Combine multiple property types on single geometry

Code example:

use lib3mf_core::Model;

let model = Model::from_file("textured.3mf")?;

// Access textures
for (id, texture) in model.resources.iter_textures() {
    println!("Texture {}: {} ({}x{})",
        id.0,
        texture.path,
        texture.width,
        texture.height
    );
}

// Access base materials
for (id, material_group) in model.resources.iter_base_materials() {
    for (idx, material) in material_group.materials.iter().enumerate() {
        println!("Material {}/{}: {} - #{:06X}",
            id.0,
            idx,
            material.name,
            material.color & 0xFFFFFF  // RGB only
        );
    }
}

Use cases:

• Full-color 3D printing
• Texture mapping from CAD
• Multi-material printing
• Visual fidelity in manufacturing

Specification: Materials Extension v1.2.1

Production Extension (v1.1.2)

Purpose: Track manufacturing metadata like UUIDs, part numbers, and production paths.

Features:

• UUIDs — Unique identifiers for each build item
• Part Numbers — Manufacturing part numbers
• Production Path — Hierarchical organization of parts

Code example:

for item in &model.build.items {
    if let Some(uuid) = &item.uuid {
        println!("Build item {} has UUID: {}", item.object_id.0, uuid);
    }
    if let Some(part_number) = &item.part_number {
        println!("  Part number: {}", part_number);
    }
}

Use cases:

• Manufacturing tracking
• Inventory management
• Production workflow integration
• Quality assurance

Specification: Production Extension v1.1.2

Beam Lattice Extension (v1.2.0)

Purpose: Define structural lattice geometries as cylindrical beams connecting vertices.

Features:

• Beam Sets — Collections of beams with shared radius
• Cap Modes — Sphere, hemisphere, or butt caps at beam endpoints
• Clipping Modes — How beams interact at intersections
• Precision Radii — Specify exact beam thickness

Code example:

use lib3mf_core::model::Geometry;

for (id, obj) in model.resources.iter_objects() {
    if let Geometry::BeamLattice(lattice) = &obj.geometry {
        println!("Object {} is a beam lattice:", id.0);
        println!("  Min length: {}", lattice.min_length);
        println!("  Beam sets: {}", lattice.beam_sets.len());
        for beam_set in &lattice.beam_sets {
            println!("    Beams: {}, Radius: {}",
                beam_set.beams.len(),
                beam_set.radius
            );
        }
    }
}

Use cases:

• Structural optimization
• Lightweight mechanical parts
• Heat exchangers
• Medical implants (porous structures)

Specification: Beam Lattice Extension v1.2.0

Slice Extension (v1.0.2)

Purpose: Pre-sliced 2D layer data for DLP/SLA resin printers.

Features:

• Slice Stacks — Ordered layers with Z-heights
• 2D Polygons — Per-layer geometry as closed polygons
• Multi-Material Slices — Different materials per layer
• External Slice Refs — Reference external slice files

Code example:

use lib3mf_core::model::Geometry;

for (id, obj) in model.resources.iter_objects() {
    if let Some(slice_stack_id) = obj.slice_stack_id {
        println!("Object {} references slice stack {}", id.0, slice_stack_id.0);

        if let Some(stack) = model.resources.get_slice_stack(slice_stack_id) {
            println!("  Layers: {}", stack.slices.len());
        }
    }
}

Use cases:

• SLA/DLP resin printing
• Pre-processed slicing workflows
• Layer-based manufacturing
• Optimized print files

Specification: Slice Extension v1.0.2

Volumetric Extension (v0.8.0)

Purpose: Voxel-based geometry representation for volume data.

Features:

• Volumetric Stacks — 3D voxel grids
• Field-Based Volumes — Continuous field representations
• Image Stacks — Layer-by-layer image data

Code example:

for (id, stack) in model.resources.iter_volumetric_stacks() {
    println!("Volumetric stack {}: {} layers", id.0, stack.layers.len());
}

Use cases:

• Medical imaging (CT/MRI to 3D print)
• Scientific visualization
• Voxel-based manufacturing
• Material density variation

Specification: Volumetric Extension v0.8.0

Secure Content Extension (v1.0.2)

Purpose: Digital signatures and content encryption for secure manufacturing.

Features:

• XML-DSIG — Digital signatures for authenticity verification
• XML-ENC — AES-GCM content encryption
• X.509 Certificates — Certificate chain validation
• RSA Public Key — Asymmetric cryptography

Requires: crypto feature flag

Code example:

#[cfg(feature = "crypto")]
use lib3mf_core::crypto::verify_signature;

#[cfg(feature = "crypto")]
fn check_signature(model: &Model) -> Result<bool> {
    if let Some(signature) = &model.signature {
        verify_signature(signature)
    } else {
        Ok(false)  // No signature present
    }
}

Use cases:

• Intellectual property protection
• Manufacturing authenticity
• Regulatory compliance
• Trusted supply chains

Specification: Secure Content Extension v1.0.2

Boolean Operations Extension (v1.1.1)

Purpose: Constructive solid geometry operations (union, difference, intersection).

Features:

• Union — Combine meshes
• Difference — Subtract mesh from another
• Intersection — Keep only overlapping volume
• Transform Matrices — Position operands
• Nested Operations — Boolean trees

Code example:

use lib3mf_core::model::Geometry;

for (id, obj) in model.resources.iter_objects() {
    if let Geometry::BooleanShape(boolean) = &obj.geometry {
        println!("Boolean operation: {:?}", boolean.operation);
        println!("  Operands: {}", boolean.operands.len());
    }
}

Use cases:

• CAD modeling workflows
• Complex geometry construction
• Parametric design
• Procedural generation

Note: lib3mf-rs parses and writes boolean operations but does not evaluate them (geometry processing is left to slicers/CAD software).

Specification: Boolean Operations Extension v1.1.1

Displacement Extension (v1.0.0)

Purpose: Texture-driven surface modification for detailed surface features.

Features:

• Displacement Maps — Grayscale textures define surface offset
• Normal Maps — RGB textures for surface normal perturbation
• Texture Coordinates — UV mapping per vertex
• Scale Factors — Control displacement intensity

Code example:

use lib3mf_core::model::Geometry;

for (id, obj) in model.resources.iter_objects() {
    if let Geometry::DisplacementMesh(displacement) = &obj.geometry {
        println!("Displacement mesh {}:", id.0);
        println!("  Texture: {}", displacement.texture_id.0);
        println!("  Scale: {}", displacement.scale);
    }
}

Use cases:

• High-detail surface textures
• Realistic skin/terrain
• Efficient detail representation
• Artistic surface effects

Note: lib3mf-rs parses displacement data but does not evaluate/tessellate it (surface subdivision is left to renderers).

Specification: Displacement Extension v1.0.0

Detecting Extensions in Files

You can check which extensions a file uses:

use lib3mf_core::Model;

let model = Model::from_file("model.3mf")?;
let stats = model.compute_stats()?;

println!("Extensions used:");
for extension in &stats.extensions {
    println!("  - {}", extension);
}

Extensions are detected automatically during parsing based on XML namespaces.

Vendor Extensions

Beyond official 3MF Consortium extensions, lib3mf-rs supports some vendor-specific extensions:

Bambu Studio Project Files:

• Multi-plate layouts
• Filament metadata
• Print time estimates
• Machine settings

These are parsed but not officially documented by the 3MF Consortium.

Next Steps

• Architecture — How extensions are integrated into lib3mf-rs
• API Reference — Detailed extension data structures
• Examples — Code examples for each extension