Crate eulumdat 

eulumdat

A Rust library for parsing, writing, and validating EULUMDAT (LDT) and IES photometric files.

About EULUMDAT

EULUMDAT (European Lumen Data format) is a photometric data file format used primarily in Europe for specifying luminous intensity distributions from light sources such as lamps and luminaires. The format was proposed by Axel Stockmar (Light Consult Inc., Berlin) in 1990 and uses the .ldt file extension.

The format is documented in:

• Stockmar, A. W. (1990): “EULUMDAT - ein Leuchtendatenformat für den europäischen Beleuchtungsplaner”, Tagungsband Licht ’90, pp. 641-644.
• Stockmar, A. W. (1998): “EULUMDAT/2 - Extended Version of a Well Established Luminaire Data Format”, CIBSE National Lighting Conference 1998, pp. 353-362.

EULUMDAT vs IES

Feature	EULUMDAT (.ldt)	IES (.ies)
Region	Europe	North America
Standard	Stockmar 1990	IESNA LM-63-2002
Angle convention	C-planes from 0°	Horizontal/vertical angles
Symmetry	5 types (Isym 0-4)	5 types

Features

• Parse LDT files - Full EULUMDAT format support with European decimal handling (comma as separator)
• Write LDT files - Roundtrip-tested output generation
• Export to IES - IESNA LM-63-2002 format export
• Validation - 44 validation constraints with detailed warnings
• Symmetry handling - 5 symmetry types with automatic data expansion
• Photometric calculations - Downward flux, beam angles, utilization factors
• BUG Rating - IESNA TM-15-11 Backlight-Uplight-Glare calculations
• Diagram generation - Platform-independent data for visualizations

EULUMDAT File Structure

The EULUMDAT format is a plain ASCII text file with the following structure:

Line	Field	Description
1	Identification	Company/database/version (max 78 chars)
2	Ityp	Type indicator (0-3)
3	Isym	Symmetry indicator (0-4)
4	Mc	Number of C-planes
5	Dc	Distance between C-planes (°)
6	Ng	Number of gamma angles per C-plane
7	Dg	Distance between gamma angles (°)
8-12	Metadata	Certificate, luminaire info, filename
13-21	Dimensions	Luminaire and luminous area dimensions (mm)
22-26	Photometric	DFF, LORL, conversion factor, tilt
26a-26b	Lamp sets	Number of lamp sets + lamp data
27	Direct ratios	10 utilization factor values
28	C-angles	Mc angle values
29	G-angles	Ng angle values
30+	Intensities	Mc × Ng intensity values (cd/klm)

Type Indicators (Ityp)

• 0: Point source with no symmetry
• 1: Point source with vertical axis symmetry
• 2: Linear luminaire
• 3: Point source with other symmetry types

Symmetry Indicators (Isym)

• 0: No symmetry - all C-planes from 0° to 360°
• 1: Vertical axis symmetry - single C-plane
• 2: C0-C180 plane symmetry - C-planes from 0° to 180°
• 3: C90-C270 plane symmetry - C-planes from 90° to 270°
• 4: Both plane symmetry - C-planes from 0° to 90°

BUG Rating System

This crate implements the IESNA TM-15-11 BUG (Backlight-Uplight-Glare) rating system for evaluating outdoor luminaire optical performance related to light trespass, sky glow, and high-angle brightness control.

The BUG rating divides the luminaire’s light distribution into zones:

• Backlight (B0-B5): Light emitted behind the luminaire
• Uplight (U0-U5): Light emitted above horizontal (contributing to sky glow)
• Glare (G0-G5): Forward high-angle light (causing visual discomfort)

Lower ratings indicate better control of unwanted light. The system is incorporated in:

• IDA/IES Model Lighting Ordinance
• LEED v4 Light Pollution Reduction credit
• California Title 24 Energy Code

Quick Start

use eulumdat::{Eulumdat, IesExporter};

// Parse from file
let ldt = Eulumdat::from_file("luminaire.ldt")?;

// Access photometric data
println!("Luminaire: {}", ldt.luminaire_name);
println!("Symmetry: {:?}", ldt.symmetry);
println!("C-planes: {}", ldt.c_angles.len());
println!("Gamma angles: {}", ldt.g_angles.len());

// Validate the data
for warning in ldt.validate() {
    println!("Warning [{}]: {}", warning.code, warning.message);
}

// Export to IES format
let ies_content = IesExporter::export(&ldt);
std::fs::write("luminaire.ies", ies_content)?;

Diagram Generation

The library provides platform-independent diagram data structures that can be rendered to SVG or used with any graphics library:

use eulumdat::{Eulumdat, diagram::*};

let ldt = Eulumdat::from_file("luminaire.ldt")?;

// Polar diagram (C0-C180 and C90-C270 curves)
let polar = PolarDiagram::from_eulumdat(&ldt);
let svg = polar.to_svg(500.0, 500.0, &SvgTheme::light());

// Butterfly diagram (3D isometric projection)
let butterfly = ButterflyDiagram::from_eulumdat(&ldt, 500.0, 400.0, 60.0);
let svg = butterfly.to_svg(500.0, 400.0, &SvgTheme::dark());

// Cartesian diagram (intensity vs gamma, max 8 curves)
let cartesian = CartesianDiagram::from_eulumdat(&ldt, 600.0, 400.0, 8);

// Heatmap diagram (2D intensity grid)
let heatmap = HeatmapDiagram::from_eulumdat(&ldt, 700.0, 500.0);

BUG Rating Calculation

use eulumdat::{Eulumdat, BugDiagram, diagram::SvgTheme};

let ldt = Eulumdat::from_file("luminaire.ldt")?;

// Calculate BUG rating
let bug = BugDiagram::from_eulumdat(&ldt);
println!("BUG Rating: {}", bug.rating); // e.g., "B2 U1 G3"

// Generate TM-15-11 BUG diagram
let bug_svg = bug.to_svg(400.0, 350.0, &SvgTheme::light());

// Generate TM-15-07 LCS (Luminaire Classification System) diagram
let lcs_svg = bug.to_lcs_svg(510.0, 315.0, &SvgTheme::light());

References

• EULUMDAT File Format (Paul Bourke)
• AGi32 EULUMDAT Documentation
• DIALux EULUMDAT Format
• IESNA LM-63-2002 Standard
• IES TM-15-11 BUG Ratings

Re-exports

pub use batch::BatchInput;

pub use batch::BatchOutput;

pub use batch::BatchStats;

pub use batch::ConversionFormat;

pub use batch::InputFormat;

pub use bug_rating::BugDiagram;

pub use bug_rating::BugRating;

pub use bug_rating::ZoneLumens;

Modules

batch

Batch conversion utilities for processing multiple EULUMDAT files at once.

bug_rating

IESNA BUG (Backlight, Uplight, Glare) Rating calculations

diagram

Diagram data generation for photometric visualizations

Structs

CieFluxCodes

CIE Flux Code values

Error

The Error type, a wrapper around a dynamic error type.

Eulumdat

Main Eulumdat data structure.

GldfPhotometricData

GLDF-compatible photometric data export.

IesExporter

IES file format exporter.

IesParser

IES file format parser.

LampSet

Lamp set configuration.

PhotometricCalculations

Photometric calculations on Eulumdat data.

PhotometricSummary

Complete photometric summary with all calculated values.

SymmetryHandler

Handler for symmetry-based operations on photometric data.

UgrParams

Parameters for UGR calculation

UgrTableValues

UGR table values for GLDF export

ValidationError

A validation error (fatal issue).

ValidationWarning

A validation warning (non-fatal issue).

ZonalLumens30

Zonal lumens in 30° zones

Enums

PhotometricType

Photometric measurement type.

Symmetry

Symmetry indicator for the luminaire.

TypeIndicator

Type indicator for the luminaire.

UnitType

Unit type for dimensions.

Functions

validate

Validate Eulumdat data and return warnings.

validate_strict

Validate strictly and return errors if critical issues are found.

Type Aliases

Result

Result<T, Error>