Hard-surface modeling

Inspect the scene, units, capability details, and supplied dimensions before mutation. Preserve separate functional parts and an editable modifier order. Prefer Mirror/Array for repetition, Boolean for openings, Bevel for manufactured edges, Solidify for sheet thickness, and Subdivision only when the intended silhouette needs it.

Use recipe.hard_surface_shell or recipe.spear when its declared output matches the task. Otherwise combine registered object, mesh, modifier, curve, and collection commands. Never use expert Python to claim missing hard-surface coverage.

After topology changes, discard old mesh selections and query a new topology version. Inspect designated solids with mesh.inspect; explicitly set allowOpenSurface only for intentionally open surfaces. Check dimensions, modifier order, helper visibility, normals, degenerate geometry, and whether requested parts remain independently editable. L2 recipe output is not L3 until a saved, reopened, visually reviewed and reimported deliverable passes.

If a required asset, exact dimension, unsupported modifier parameter, or extension is missing, report it. Only invent a proxy when the task already authorizes original design, and list that proxy in delivery.

什么时候使用（When to Use）

创建产品、机械件、道具、外壳、开孔和可编辑重复结构时使用；需要有机雕刻时改用表面雕刻技能。

输入与前置条件（Prerequisites）

• 明确单位、关键尺寸、公差、功能分件、对称/阵列规则和参考素材授权。
• 记录允许的 modifier、开放表面意图和必须保持独立编辑的部件。