Sap of the Pará rubber tree, tapped, smoked, and cooked with sulfur until it remembers its shape. Stretches and snaps back like nothing else cheap. Tires, erasers, gaskets, the soles of every shoe before the 1980s. Goes off slowly in sunlight; the smell is the breakdown of double bonds.
Cis-1,4-polyisoprene from Hevea brasiliensis, vulcanized with sulfur (Goodyear, 1839) to crosslink the chains. Tensile strength 17–25 MPa, elongation at break 600–900%, Shore A hardness tunable from gum-soft (~30) to ebonite-hard (~95) by sulfur loading. Glass transition ~−70 °C — stays elastic to deep cold. Ozone- and UV-sensitive; antiozonant additives slow but don't stop chain-scission.
Principled BSDF defaults derived from the sphere matte finish. Reasonable seed for Blender, Substance, Keyshot, Rhino — tune per material. Or grab the whole library at once: ForMaterials library →
# finish: matte albedo #3a2f28 metallic 0.00 roughness 0.75 ior 1.45 transmission 0.00 clearcoat 0.00 sheen 0.00 anisotropic 0.00
{
"albedo": "#3a2f28",
"metallic": 0.0,
"roughness": 0.75,
"ior": 1.45,
"transmission": 0.0,
"clearcoat": 0.0,
"sheen": 0.0,
"anisotropic": 0.0
}
# Blender 4.x — Principled BSDF
# Natural Rubber (vulcanized) · finish: matte
import bpy
mat = bpy.data.materials.new(name="mat_natural_rubber")
mat.use_nodes = True
bsdf = mat.node_tree.nodes["Principled BSDF"]
bsdf.inputs["Base Color"].default_value = (0.0423, 0.0284, 0.0212, 1.0)
bsdf.inputs["Metallic"].default_value = 0.000
bsdf.inputs["Roughness"].default_value = 0.750
bsdf.inputs["IOR"].default_value = 1.450
bsdf.inputs["Transmission Weight"].default_value = 0.000
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
# Natural Rubber (vulcanized) · finish: matte
# Run from Window → Scripting Console
import lux
mat = lux.createMaterial(name="mat_natural_rubber", materialType="Generic")
mat.setProperty("diffuse", (58, 47, 40)) # 8-bit sRGB
mat.setProperty("metallic", 0.000)
mat.setProperty("roughness", 0.750)
mat.setProperty("indexOfRefraction", 1.450)
mat.setProperty("transparency", 0.000)
mat.setProperty("coatingWeight", 0.000)
{
"_format": "Substance Designer / Painter \u2014 pbrMetalRough constants",
"_about": "Natural Rubber (vulcanized) \u00b7 finish: matte",
"baseColor": {
"r": 0.0423,
"g": 0.0284,
"b": 0.0212
},
"metallic": 0.0,
"roughness": 0.75,
"ior": 1.45,
"opacity": 1.0,
"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_natural_rubber",
"pbrMetallicRoughness": {
"baseColorFactor": [
0.0423,
0.0284,
0.0212,
1.0
],
"metallicFactor": 0.0,
"roughnessFactor": 0.75
},
"extensions": {
"KHR_materials_ior": {
"ior": 1.45
}
}
}
]
}# USD Preview Surface — UsdShade.MaterialLook prim attributes
# Natural Rubber (vulcanized) · finish: matte
def Material "mat_natural_rubber" {
token outputs:surface.connect = </mat_natural_rubber/PreviewSurface.outputs:surface>
def Shader "PreviewSurface" {
uniform token info:id = "UsdPreviewSurface"
color3f inputs:diffuseColor = (0.0423, 0.0284, 0.0212)
float inputs:metallic = 0.000
float inputs:roughness = 0.750
float inputs:ior = 1.450
float inputs:opacity = 1.000
float inputs:clearcoat = 0.000
token outputs:surface
}
}
International Rubber Study Group technical literature; ASTM D2000 elastomer classification.
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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