py-materials 2.1.1

Hierarchical material library for CAD applications with build123d integration

mat

Material database for CAD and Monte Carlo particle transport.

Shared TOML data files with language-specific packages:

Package	Language	Registry	Import
py-materials	Python	PyPI	import pymat
rs-materials	Rust	crates.io	use rs_materials::...

Features

Python (py-materials)

• Hierarchical Materials: Chain grades, tempers, treatments, and vendors
• Property Inheritance: Children inherit parent properties unless overridden
• Lazy Loading: Categories load on first access
• build123d Integration: Apply materials to shapes with automatic mass calculation
• PBR Rendering: Physically-based rendering properties for visualization
• periodictable Integration: Auto-fill density from chemical formulas
• Factory Functions: Temperature/pressure-dependent materials (water, air, saline)

Rust (rs-materials)

• TOML Database Reader: Loads all 7 material categories with property inheritance
• Formula Parser: Fractional stoichiometry (Lu1.8Y0.2SiO5 → element/count pairs)
• Mass/Atom Fraction Conversion: Bidirectional with roundtrip correctness
• Scintillator Properties: Light yield, decay time, emission peak, refractive index
• Thread-Safe: Send + Sync for Arc sharing in multi-threaded transport engines

Installation

Python

# With uv (recommended)
uv add git+https://github.com/MorePET/mat.git@latest

# Or specify version
uv add git+https://github.com/MorePET/mat.git@v1.0.0

Rust

[dependencies]
rs-materials = { git = "https://github.com/MorePET/mat.git" }

Quick Start

Creating Materials

    Create materials with convenient parameters:

from pymat import Material

        # Using convenience parameters
        steel = Material(name="Steel", density=7.85)
        # With visualization color
        aluminum = Material(name="Aluminum", density=2.7, color=(0.88, 0.88, 0.88))
        # With formula
        lyso = Material(name="LYSO", formula="Lu1.8Y0.2SiO5", density=7.1)
        assert lyso.formula == "Lu1.8Y0.2SiO5"

Using Property Groups

    Define multiple properties at once using property group dictionaries:

from pymat import Material

        # Define steel with multiple property groups
        steel = Material(
            name="Stainless Steel 304",
            mechanical={"density": 8.0, "youngs_modulus": 193, "yield_strength": 170},
            thermal={"melting_point": 1450, "thermal_conductivity": 15.1},
            pbr={"base_color": (0.75, 0.75, 0.77, 1.0), "metallic": 1.0}
        )        assert steel.properties.pbr.metallic == 1.0

Applying Materials to Shapes

    Apply materials to build123d shapes for visualization and mass calculation:

from build123d import Box
        from pymat import Material

        # Create material
        steel = Material(name="Steel", density=7.85, color=(0.7, 0.7, 0.7))

        # Create shape and apply material
        box = Box(10, 10, 10)
        steel.apply_to(box)        assert box.color is not None

Chainable Material Hierarchy

    Build hierarchies with grades, tempers, and treatments:

from pymat import Material

        # Create base stainless steel
        stainless = Material(
            name="Stainless Steel",
            density=8.0,
            thermal={"melting_point": 1450}
        )

        # Add grade
        s304 = stainless.grade_("304", name="SS 304", mechanical={"yield_strength": 170})
        # Add treatment
        passivated = s304.treatment_("passivated", name="SS 304 Passivated")        assert passivated.density == 8.0  # Inherited through chain

Direct Material Access

    Load materials and access them directly from the library:

from pymat import stainless, aluminum, lyso

        # Direct access to materials
        s316L = stainless.s316L
        al6061 = aluminum.a6061
        lyso_crystal = lyso
        assert "LYSO" in lyso_crystal.name

Physics Properties vs Visualization

    Understand the difference between measured optical properties (physics)
    and rendering properties (visualization):

from pymat import Material

        # Create transparent material
        glass = Material(
            name="Optical Glass",
            color=(0.9, 0.9, 0.9, 0.8),  # Visual: 80% opaque white
            optical={"transparency": 95, "refractive_index": 1.517},  # Physics: 95% transmission
            pbr={"transmission": 0.8}  # Rendering: how transparent it looks
        )

        # Physics properties (measured)
        # Visualization properties (rendering)        assert glass.properties.pbr.transmission == 0.8

Scintillator-Specific Properties

    Define detector crystals with optical physics properties:

from pymat import Material

        lyso_crystal = Material(
            name="LYSO:Ce Crystal",
            density=7.1,
            optical={
                "refractive_index": 1.82,
                "transparency": 92,
                "light_yield": 32000,  # photons/MeV
                "decay_time": 41,  # ns
                "emission_peak": 420,  # nm
            },
            pbr={"base_color": (0.0, 1.0, 1.0, 0.85), "transmission": 0.85}
        )        assert lyso_crystal.properties.pbr.transmission == 0.85

Temperature-Dependent Materials

    Use factory functions for materials with properties that depend on external parameters:

from pymat.factories import water

        # Water at different temperatures
        cold_water = water(4)      # Max density
        room_water = water(20)     # Room temperature
        hot_water = water(80)      # Heated
        # Verify realistic values        assert 0.95 < hot_water.density < 0.98

Air at Different Conditions

    Create air material at specific temperature and pressure:

from pymat.factories import air

        sea_level = air(15, 1.0)      # 15°C, 1 atm
        high_altitude = air(15, 0.5)  # 15°C, 0.5 atm (5500m)

        assert sea_level.density > high_altitude.density

Saline Solutions

    Create solutions with specific concentration and temperature:

from pymat.factories import saline, water

        # Physiological saline at body temperature
        phantom = saline(0.9, temperature_c=37)
        # Saline is slightly denser than pure water at same temperature
        pure_water_37 = water(37)
        # Seawater (3.5% NaCl) at 20°C
        seawater = saline(3.5, temperature_c=20)
        # Higher concentration = higher density
        assert seawater.density > phantom.density

Loading Metal Materials

    Access various metal materials from the metals category:

from pymat import stainless, aluminum, copper

        # Stainless steel variants
        s304 = stainless.s304
        s316L = stainless.s316L
        # Aluminum alloys
        al6061 = aluminum.a6061
        al7075 = aluminum.a7075
        # Copper
        copper_material = copper
        assert copper_material.density == 8.96

Plastic Materials

    Access plastic materials for 3D printing and engineering:

from pymat import peek, pla, pc, pmma

        # Engineering plastics
        # 3D printing plastics
        # Transparent plastics        assert pc.properties.optical.transparency == 89

Scintillator Crystals

    Access scintillator materials for radiation detectors:

from pymat import lyso, bgo, nai

        # LYSO crystal
        # BGO crystal
        # NaI crystal
        assert nai.properties.optical.light_yield == 38000

Gas Materials

    Access gases for simulation and detector design:

from pymat import air, nitrogen, argon, helium, xenon

        # Common gases at STP
        # Detector gases
        assert argon.properties.compliance.radiation_resistant == True

Property Inheritance

    Child materials inherit properties from parents unless overridden:

from pymat import Material

        # Create material hierarchy
        root = Material(
            name="Base",
            density=7.8,
            thermal={"melting_point": 1500, "thermal_conductivity": 50}
        )

        grade1 = root.grade_("G1", mechanical={"yield_strength": 400})
        # Override inherited property
        grade2 = root.grade_("G2", thermal={"melting_point": 1600})
        assert grade2.properties.thermal.melting_point == 1600  # Overridden

Automatic Mass Calculation

    Materials with density automatically calculate shape mass:

from build123d import Box
        from pymat import stainless, aluminum

        # 10x10x10 mm³ box = 1000 mm³ = 1 cm³
        steel_box = Box(10, 10, 10)
        stainless.apply_to(steel_box)

        # Density = 8.0 g/cm³, Volume = 1 cm³ → Mass = 8.0 g
        # Aluminum box
        al_box = Box(10, 10, 10)
        aluminum.apply_to(al_box)

        # Density = 2.7 g/cm³ → Mass = 2.7 g
        assert 2.6 < al_box.mass < 2.8

Material Visualization

    Materials render with appropriate colors for visualization:

from build123d import Box
        from pymat import stainless, aluminum, lyso

        # Create shapes
        steel_part = Box(10, 10, 10)
        al_part = Box(10, 10, 10)
        crystal = Box(10, 10, 10)

        # Apply materials
        stainless.apply_to(steel_part)
        aluminum.apply_to(al_part)
        lyso.apply_to(crystal)

        # Verify colors are set
        # Colors should differ        assert crystal.color != steel_part.color

Material Categories

• Metals: Stainless steel, aluminum, copper, tungsten, lead, titanium, brass
• Scintillators: LYSO, BGO, NaI, CsI, LaBr3, PWO, plastic scintillators
• Plastics: PEEK, Delrin, Ultem, PTFE, ESR, Nylon, PLA, ABS, PETG, TPU, PMMA, PE, PC
• Ceramics: Alumina, Macor, Zirconia, Glass (borosilicate, fused silica, BK7)
• Electronics: FR4, Rogers, Kapton, copper PCB, solder, ferrite
• Liquids: Water, Heavy Water, Mineral Oil, Glycerol, Silicone Oil
• Gases: Air, Nitrogen, Oxygen, Argon, CO₂, Helium, Hydrogen, Neon, Xenon, Methane, Vacuum

Property Groups

Each material can have properties organized in these domains:

• Mechanical: density, Young's modulus, yield strength, hardness
• Thermal: melting point, thermal conductivity, expansion coefficient
• Electrical: resistivity, conductivity, dielectric constant
• Optical: refractive index, transparency, light yield (PHYSICS - measured values)
• PBR: base color, metallic, roughness (VISUALIZATION - rendering appearance)
• Manufacturing: machinability, printability, weldability
• Compliance: RoHS, REACH, food-safe, biocompatible
• Sourcing: cost, availability, suppliers

Advanced Usage

Custom Materials

Create materials using property group dictionaries:

from pymat import Material

my_material = Material(
    name="Custom Alloy",
    mechanical={
        "density": 8.1,
        "youngs_modulus": 200,
        "yield_strength": 450
    },
    pbr={
        "base_color": (0.7, 0.7, 0.75, 1.0),
        "metallic": 1.0,
        "roughness": 0.4
    }
)

Loading from TOML

from pymat import load_toml

materials = load_toml("my_materials.toml")
my_material = materials["my_material"]

Enrichment from Chemical Formulas

from pymat import enrich_from_periodictable

material = Material(name="Aluminum Oxide", formula="Al2O3")
enrich_from_periodictable(material)
print(material.density)  # ~3.95 g/cm³

Optical vs PBR Properties

Important: Understand the distinction between physics and visualization:

• Optical Properties (optical.*): Measured/calculated physical values

  • transparency: % light transmission (measured)
  • refractive_index: optical property (measured)
  • light_yield: scintillator brightness (measured)

• PBR Properties (pbr.*): Rendering/visualization parameters

  • base_color: RGBA values (0-1) for display
  • transmission: how transparent it LOOKS in renders
  • metallic: surface finish appearance
  • roughness: surface roughness appearance

These can differ intentionally! A material might be physically transparent (95% optical transmission) but rendered opaque (0% pbr transmission) for CAD clarity.

License

MIT

Links

• GitHub: https://github.com/MorePET/mat
• Issues: https://github.com/MorePET/mat/issues