The plastic of every clear water bottle, every soda bottle, every clamshell food package, every blister pack, every Mylar Christmas balloon. PET is a thermoplastic polyester (the same chemistry as polyester fiber for clothes — the bottle and the t-shirt are the same polymer in different physical forms) developed in the 1940s and dominant in beverage packaging since the 1970s shift away from glass. The polymer is clear, tough, recyclable in the standard #1 stream, and processable by the most common plastic-forming methods (injection-stretch-blow molding for bottles, thermoforming for clamshells, fiber spinning for textiles, film extrusion for Mylar). Recycled PET (rPET) is the closed-loop version — bottle-to-bottle recycling has been industrially proven since 2010 and now accounts for a meaningful share of new-bottle production. Buy from McMaster, Curbell Plastics for sheet/rod stock, or directly from converters for blow-molded preforms.
Thermoplastic semi-crystalline polyester, structural unit -[O-CH2-CH2-O-OC-C6H4-CO]n-, glass transition Tg 75 °C, melting Tm 250-260 °C. Density 1380 kg/m³ (amorphous) to 1450 kg/m³ (crystalline; bottle PET is amorphous from rapid cooling, fiber PET is partially oriented and crystalline). Tensile strength 55-80 MPa. Tensile modulus 2.8-4.1 GPa. Elongation at break 50-300 percent depending on grade. Heat-deflection temperature 65-70 °C (the limit on hot-fill applications — soft drinks fine, hot coffee not). Optically clear in amorphous form (visible light transmission > 90 percent at typical bottle wall thickness 0.3 mm). Bottle-grade PET is processed by injection-stretch-blow molding: injection-mold a preform (test-tube shape with the threaded neck), reheat to ~100 °C, blow into bottle mold while stretching biaxially — the bi-axial orientation introduces strength + clarity that compounds compounded into the polymer cannot match. Mylar film is biaxially-oriented PET (BoPET); the orientation gives the dimensional stability and tear resistance that distinguishes Mylar from cast PET. Recycled PET (rPET) processes essentially identically to virgin PET; food-contact rPET requires FDA letters of no objection that confirm decontamination during the recycling process. Resin identification code 1 (PET).
Plastic water bottles are rigged with tape to the body, to the chest, shoulders, and arms, protecting against the blows of the nightsticks. One type of street-level citizen-making, with materials from the local deli, is set against the police force's sophisticated design, equipment, and training.
Principled BSDF defaults derived from the sphere transparent finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material. Or grab the whole library at once: ForMaterials library →
# finish: transparent albedo #e8f0f4 metallic 0.00 roughness 0.05 ior 1.50 transmission 1.00 clearcoat 0.00 sheen 0.00 anisotropic 0.00 thickness 1.00 attenuation_distance 0.60
{
"albedo": "#e8f0f4",
"metallic": 0.0,
"roughness": 0.05,
"ior": 1.5,
"transmission": 1.0,
"clearcoat": 0.0,
"sheen": 0.0,
"anisotropic": 0.0,
"thickness": 1.0,
"attenuation_distance": 0.6
}
# Blender 4.x — Principled BSDF
# PET (Polyethylene Terephthalate, Clear Bottle Grade) · finish: transparent
import bpy
mat = bpy.data.materials.new(name="mat_pet_clear_bottle")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value = (0.807, 0.8714, 0.9047, 1.0)
bsdf.inputs["Metallic"].default_value = 0.000
bsdf.inputs["Roughness"].default_value = 0.050
bsdf.inputs["IOR"].default_value = 1.500
bsdf.inputs["Transmission Weight"].default_value = 1.000
bsdf.inputs["Coat Weight"].default_value = 0.000
bsdf.inputs["Sheen Weight"].default_value = 0.000
bsdf.inputs["Anisotropic"].default_value = 0.000
# KeyShot 11+ — lux Python API, Generic material
# PET (Polyethylene Terephthalate, Clear Bottle Grade) · finish: transparent
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_pet_clear_bottle", materialType="Generic")
mat.setProperty("diffuse", (232, 240, 244)) # 8-bit sRGB
mat.setProperty("metallic", 0.000)
mat.setProperty("roughness", 0.050)
mat.setProperty("indexOfRefraction", 1.500)
mat.setProperty("transparency", 1.000)
mat.setProperty("coatingWeight", 0.000)
{
"_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
"_about": "PET (Polyethylene Terephthalate, Clear Bottle Grade) \u00b7 finish: transparent",
"baseColor": {
"r": 0.807,
"g": 0.8714,
"b": 0.9047
},
"metallic": 0.0,
"roughness": 0.05,
"ior": 1.5,
"opacity": 0.0,
"anisotropyLevel": 0.0,
"_notes": "Channels listed are the standard Substance pbrMetalRough output. Drop into a Uniform Color node per channel, or as the constant input on a layered stack."
}{
"asset": {
"version": "2.0",
"generator": "ForMatter"
},
"materials": [
{
"name": "mat_pet_clear_bottle",
"pbrMetallicRoughness": {
"baseColorFactor": [
0.807,
0.8714,
0.9047,
1.0
],
"metallicFactor": 0.0,
"roughnessFactor": 0.05
},
"extensions": {
"KHR_materials_transmission": {
"transmissionFactor": 1.0
}
}
}
]
}# USD Preview Surface — UsdShade.MaterialLook prim attributes
# PET (Polyethylene Terephthalate, Clear Bottle Grade) · finish: transparent
def Material "mat_pet_clear_bottle" {
token outputs:surface.connect = </mat_pet_clear_bottle/PreviewSurface.outputs:surface>
def Shader "PreviewSurface" {
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = (0.807, 0.8714, 0.9047)
float inputs:metallic = 0.000
float inputs:roughness = 0.050
float inputs:ior = 1.500
float inputs:opacity = 0.000
float inputs:clearcoat = 0.000
token outputs:surface
}
}
Bottle-grade PET sheet — clear, optically clean, not as strong as cast PMMA. Mills cleaner than HDPE but is more brittle than ABS. Common as recycled sheet from compressed bottle stock for student projects.
Onsrud Cutter plastic feeds & speeds (PET / PETE table); Curbell Plastics PET sheet-machining notes.
→ try this material in swarfSPI / PLASTICS recycling guide (RIC 1); APR (Association of Plastic Recyclers) PET design-for-recyclability guide; Coca-Cola PlantBottle technical literature.
House vocabulary — terms ForMatter uses with intent.
Materials and processes for people who design and make things.
A local-first library of materials, processes, applications, and finishes — equal weight, citable everywhere, with cost-over-volume curves, trade-off profiles, equipment-tier filters, and second-life paths layered onto the data so a student can move from "what is this" toward "what's actually buildable here, now, by me." Part of the renato.design ecosystem — sibling of Plenum, Specimen, Ingenue, gesture, graf, and the Renato Rhino plug-ins. Form and matter, inseparable.
Half of teaching materials is teaching how the material is made into the thing. The standard subscription library was always light on that half. The wedge here isn't better samples or a prettier interface — it's treating Process as a peer entity, not a footnote.
Conway's Material World on raw materials, Lefteri's Making It on processes, Forty's Concrete and Culture, Sparke's Design in Context, Bürdek's Design: History, Theory and Practice of Product Design, Schröpfer's Material Design on materials in architecture, Winchester's The Perfectionists on tolerance, Minshall's Your Life Is Manufactured on the global supply chain, von Busch's Making Trouble on material activism, Were's How Materials Matter, Hegger / Drexler / Zeumer's Basics Materials, Untracht and McCreight on metalsmithing, USDA Forest Products Lab on woods, GIA on gemstones, Schott / CoorsTek / Toray / Owens Corning datasheets, MakeItFrom for verifiable property numbers, ASM Handbook, ISO standards. Museum holdings draw from the Met, MAD, V&A, Smithsonian American Art Museum, Newark Museum of Art, British Museum, Heard Museum, Smithsonian NMAI, Eiteljorg Museum, Philadelphia Museum of Art, Cranbrook Art Museum, and Grand Rapids Art Museum — collection-record permalinks only, designer overview pages and exhibition listings excluded. Voice blocks now ride on every entry kind — material, process, application, and finish — and include Ruskin on iron, Anni Albers on twining, Greg Lynn on the shred-and-teeth NURBS lineage, Pugin on the metal that won't be hammered, Barthes / Yanagi / Benjamin channeled within their philosophy; Sparke, Bürdek, Forty, Conway, Schröpfer, Minshall, von Busch, Lefteri, Pat Pruitt, Mary Lee Hu, Tom Joyce, Albert Paley, and the rest of the contemporary makers quoted verbatim with citation. All cited.
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