> For the complete documentation index, see [llms.txt](https://manual-1-3.karamba3d.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://manual-1-3.karamba3d.com/chinese_1_3_3/2-getting-started/2-getting-started-1/karamba3d-entities.md).

# 2.1: Karamba3D实体

Grasshopper（GH）是一种面向对象的可视化脚本环境，可提供点、曲线、面等元素，并用于几何计算。用户可在工具栏**“Params（参数）”**的子目录**“Geometry（几何体）”**中查看所有可用几何项。此外，Karamba3D中还增加了七个用于构建结构模型的实体。

| Entity            | Typology                       |
| ----------------- | ------------------------------ |
| Model（模型）         | 包含了与结构相关的所有信息。                 |
| Element（构件）       | 可以是梁、桁架、壳体或弹性元件。               |
| Element Set（构件集）  | 按照给定顺序将构件进行组合，用户可在通用名称下访问各个构件。 |
| Joint（连接）         | 定义相邻构件之间的关联性。                  |
| Load（荷载）          | 施加于结构上的外力。                     |
| Cross-section（断面） | 定义结构构件的断面几何形状。                 |
| Material（材料）      | 提供关于断面构成的物理行为信息。               |
| Support（支撑件）      | 定义结构与地面的连接方式。                  |

Karamba3D的分析对象在运行方面与 GH 实体相似。

* 可被存储于存储器中（详见Karamba3D工具栏的**“Params（参数）”**子目录）
* 将其接入面板时可将相关基本属性转换为文本信息，并提供文本输出。

## 默认设置

在构建结构模型时，并不需要呈现所有上述实体。Karamba3D假设材料和断面均为默认设置。

* 若未指定材料，Karamba3D所有默认断面均为钢材（S235根据 EC3的$$f\_{yk} =  23.5 kN/cm^2$$)。
* Karamba3D的默认梁是外径为$$114.4mm$$壁厚为$$4mm$$的圆形空心断面（CHS），壳体的默认厚度为$$10mm$$。


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