"""Metric threaded rod (DIN 976-1 form A) and double-ended stud, M2 to M36, any length.

Envelope model for assemblies: a plain cylinder at the nominal thread diameter d (the thread is not modelled).
One end is on the XY plane at the origin, the rod along +Z; `length` is the overall length.
"""
from steve import Model

size = "M8"  # Thread size
length = 100  # mm Length (overall)
material = "steel"  # Material

# DIN 976-1:2016-09 size table (https://fasten.it/en/Norms/Norm/DIN%20976-1): size -> nominal (major) diameter d, mm
# (Md: d = M-number by the designation, ISO 261 coarse pitch series)
DIAMETERS = {
    "M2": 2.0,
    "M2.5": 2.5,
    "M3": 3.0,
    "M4": 4.0,
    "M5": 5.0,
    "M6": 6.0,
    "M8": 8.0,
    "M10": 10.0,
    "M12": 12.0,
    "M14": 14.0,
    "M16": 16.0,
    "M20": 20.0,
    "M24": 24.0,
    "M30": 30.0,
    "M36": 36.0,
}
# material choice: (STEVE material library id, appearance colour)
MATERIALS = {
    "steel": ("steel-generic", "#b4b8bd"),        # property class 4.8 / 8.8, zinc plated
    "stainless-a2": ("stainless-304", "#c9ccd0"),  # ISO 3506-1 A2-70
    "stainless-a4": ("stainless-316", "#c9ccd0"),  # ISO 3506-1 A4-70
    "brass": ("brass", "#c8a44d"),
}

d = DIAMETERS[size]
material_id, colour = MATERIALS[material]

model = Model()
with model.sketch("rod_sketch", on="XY", name="Section") as sk:
    sk.circle("rod_circle", (0, 0), d / 2)
model.extrude("rod", "rod_sketch", distance=length, name="Rod")
model.material(material_id, color=colour)
result = model.result()