BathAfrica: Add rewritten practical lesson with steps, code and expected results

2026-10-29T21:00:56Z

Add rewritten practical lesson with steps, code and expected results

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__NOTOC__
{{OpenSite scope}}
{{OpenSite lesson
|id=opensite.help.create-a-material
|summary=Create a user-defined practice material and read its properties through the document object interface.
|prerequisites=A matching build with the material API. User-material operations use <code>document.workspace</code>; the catalog-provider registration capability is a separate concern.
|steps==== Start with a new document ===
Use <code>document.new</code> to obtain a live document handle. In the desktop, the material extension exposes Add Material and Material Manager when available.

=== Enter the practice values ===
Use E = 210 GPa, ν = 0.28 and density = 7850 kg/m³. The helper takes SI values: <code>elastic_pa=210e9</code>, not 210. The values are educational inputs, not an approved standard grade.

=== Create and validate ===
Call <code>material_create_user</code>, retain the returned object ID, and call <code>material_validate</code>. Validation concerns the material record; it does not approve a design.

=== Read the object and check shear modulus ===
Resolve the object using <code>doc.get_object(id)</code>. Read E in GPa and compare G with E / (2 × (1 + ν)); expected G is 82.03125 GPa.

|result=The created object exposes E = 210 GPa. The listed derived shear modulus is approximately 82.03125 GPa and the validation result is reported.
|limitations=No production catalog grade or design-standard compliance is claimed. Save the document separately if you want to retain the new material.
}}

== Complete example ==
{{Code|lang=python|code=<nowiki>import opensite

doc = opensite.execute("document.new", {})["document"]
values = {
"name": "Practice steel", "family": "steel", "role": "structural_steel",
"has_elastic": True, "elastic_pa": 210.0e9,
"has_poisson": True, "poisson": 0.28,
"has_mass_density": True, "mass_density": 7850.0,
"has_thermal": True, "thermal_per_k": 1.2e-5,
}
created = opensite.material_create_user(doc, values)
material = doc.get_object(created["id"])
print("Name:", material.name)
print("Elastic modulus:", material.elastic_modulus.value_in("GPa"), "GPa")
print("Validation:", opensite.material_validate(doc, created["id"])["validation"])
row = next(m for m in opensite.material_list(doc) if m["id"] == created["id"])
expected_g = 210.0e9 / (2.0 * (1.0 + 0.28))
assert abs(row["shear_modulus_pa"] - expected_g) < 1.0
print("Derived shear modulus:", row["shear_modulus_pa"] / 1e9, "GPa")</nowiki>}}

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BathAfrica: Add rewritten practical lesson with steps, code and expected results