Struct ObjExporter 

pub struct ObjExporter;

Exports 3MF Model structures to Wavefront OBJ files.

The exporter writes all mesh objects from build items to OBJ format, creating separate groups for each object and applying build item transformations.

Implementations

impl ObjExporter

pub fn write<W: Write>(model: &Model, writer: W) -> Result<()>

Writes a 3MF Model to OBJ text format.

Arguments

• model - The 3MF model to export
• writer - Any type implementing Write to receive OBJ text data

Returns

Ok(()) on successful export.

Errors

Returns Lib3mfError::Io if any write operation fails.

Format Details

• Groups: Each mesh object creates an OBJ group (g) with the object’s name or “Object”
• Vertex indices: Written as 1-based indices (OBJ convention)
• Transformations: Build item transforms are applied to vertex coordinates
• Materials: Not exported (OBJ output is geometry-only)
• Normals/UVs: Not exported

Behavior

• Only mesh objects from model.build.items are exported
• Non-mesh geometries (Components, BooleanShape, etc.) are skipped
• Vertex indices are offset correctly across multiple objects
• Each object’s vertices and faces are written in sequence

Examples

use lib3mf_converters::obj::ObjExporter;
use lib3mf_core::model::Model;
use std::fs::File;

let output = File::create("exported.obj")?;
ObjExporter::write(&model, output)?;
println!("Model exported successfully");