212 lines
5.7 KiB
Markdown
212 lines
5.7 KiB
Markdown
# freecad 二次开发文档
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## freecad 源代码目录结构
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**src/：**此目录包含 FreeCAD 的核心源代码。
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**src/App：**包含 FreeCAD 的应用程序对象的实现，如文档、事务管理和撤销/重做系统。
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**src/Base：**包含一些基本类和函数，如向量、矩阵和几何实体。
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**src/Main：**包含 FreeCAD 的主程序入口点。
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**src/Mod：**包含 FreeCAD 的各个模块和工作台的实现，如 Part、Sketcher、FEM 等。
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**src/Gui：**包含 FreeCAD 的图形用户界面（GUI）的实现，使用 Qt 框架构建。
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**src/Tools：**包含一些实用工具，如编译和构建脚本。
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**data/**：此目录包含 FreeCAD 的一些资源文件，如图标、模板、样式表等。
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**doc/：**此目录包含 FreeCAD 的开发文档，包括编码规范、开发指南等。
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**ext/：**此目录包含 FreeCAD 依赖的外部库，如 Open CASCADE、Eigen 等
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## fem步骤
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1. 创建或导入一个几何模型。
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2. 转到 FEM 工作台。
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3. 创建一个分析对象（Analysis Container）。
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4. 定义材料属性。
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5. 为模型添加约束，例如固定、力和压力。
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6. 创建一个网格，将几何体划分为有限元。
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7. 选择求解器，如 CalculiX、Elmer 或 Z88。
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8. 运行分析。
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9. 查看和分析结果。
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## python 自动创建fem分析脚本
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```python
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#! /usr/bin/env python3
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# -*- coding: utf-8 -*-
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# vim:fenc=utf-8
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#
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# Copyright © 2023 veypi <i@veypi.com>
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#
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# Distributed under terms of the Apache license.
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"""
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"""
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doc = App.newDocument("Scripted_CalculiX_Cantilever3D")
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import Part
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box_obj = doc.addObject('Part::Box', 'Box')
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box_obj.Height = box_obj.Width = 1000
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box_obj.Length = 8000
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# see how our part looks like
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import FreeCADGui
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FreeCADGui.ActiveDocument.activeView().viewAxonometric()
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FreeCADGui.SendMsgToActiveView("ViewFit")
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import ObjectsFem
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# analysis
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analysis_object = ObjectsFem.makeAnalysis(doc, "Analysis")
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# solver (we gone use the well tested CcxTools solver object)
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solver_object = ObjectsFem.makeSolverCalculixCcxTools(doc, "CalculiX")
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solver_object.GeometricalNonlinearity = 'linear'
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solver_object.ThermoMechSteadyState = True
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solver_object.MatrixSolverType = 'default'
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solver_object.IterationsControlParameterTimeUse = False
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analysis_object.addObject(solver_object)
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# material
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material_object = ObjectsFem.makeMaterialSolid(doc, "SolidMaterial")
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mat = material_object.Material
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mat['Name'] = "Steel-Generic"
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mat['YoungsModulus'] = "210000 MPa"
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mat['PoissonRatio'] = "0.30"
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mat['Density'] = "7900 kg/m^3"
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material_object.Material = mat
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analysis_object.addObject(material_object)
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# fixed_constraint
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fixed_constraint = ObjectsFem.makeConstraintFixed(doc, "FemConstraintFixed")
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fixed_constraint.References = [(doc.Box, "Face1")]
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analysis_object.addObject(fixed_constraint)
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# force_constraint
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force_constraint = ObjectsFem.makeConstraintForce(doc, "FemConstraintForce")
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force_constraint.References = [(doc.Box, "Face2")]
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force_constraint.Force = 9000000.0
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force_constraint.Direction = (doc.Box, ["Edge5"])
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force_constraint.Reversed = True
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analysis_object.addObject(force_constraint)
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## fem mesh
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femmesh_obj = ObjectsFem.makeMeshGmsh(doc, box_obj.Name + "_Mesh")
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femmesh_obj.Part = doc.Box
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doc.recompute()
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from femmesh.gmshtools import GmshTools as gt
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gmsh_mesh = gt(femmesh_obj)
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error = gmsh_mesh.create_mesh()
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print(error)
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analysis_object.addObject(femmesh_obj)
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doc.recompute()
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# activating analysis
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import FemGui
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FemGui.setActiveAnalysis(doc.Analysis)
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#from femtools import ccxtools
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#fea = ccxtools.FemToolsCcx()
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#fea.purge_results()
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#fea.run()
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from femtools import ccxtools
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fea = ccxtools.FemToolsCcx()
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fea.update_objects()
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fea.setup_working_dir()
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fea.setup_ccx()
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message = fea.check_prerequisites()
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if not message:
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fea.purge_results()
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fea.write_inp_file()
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# on error at inp file writing, the inp file path "" was returned (even if the file was written)
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# if we would write the inp file anyway, we need to again set it manually
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# fea.inp_file_name = '/tmp/FEMWB/FEMMeshGmsh.inp'
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fea.ccx_run()
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fea.load_results()
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else:
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FreeCAD.Console.PrintError(
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"Houston, we have a problem! {}\n".format(message)) # in report view
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print("Houston, we have a problem! {}\n".format(
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message)) # in Python console
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###
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# show resutlt
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for m in analysis_object.Group:
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if m.isDerivedFrom('Fem::FemResultObject'):
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result_object = m
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break
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femmesh_obj.ViewObject.setNodeDisplacementByVectors(
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result_object.NodeNumbers, result_object.DisplacementVectors)
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print(result_object.DisplacementVectors[-1])
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import time
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femmesh_obj.ViewObject.applyDisplacement(20)
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import requests
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d = requests.get(url="http://192.168.5.172:8015/file/123")
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print("|%s|" % (d.text.strip()))
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# 每秒请求服务器渲染变形程度
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n = 0
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data = 0
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while 1:
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time.sleep(0.01)
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d = requests.get(url="http://192.168.5.172:8015/file/123")
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data = int(d.text.strip())
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# 更新ui
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FreeCAD.Gui.updateGui()
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#print("%s/%s"%(n, data))
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femmesh_obj.ViewObject.applyDisplacement(n)
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if data > n:
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n = n + 1
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if data < n:
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n = n - 1
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```
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## 添加有限元fem 求解器
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[参考源码](https://github.com/FreeCAD/FreeCAD/compare/a03eb6b9625ba...dfc01ec949525)
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步骤：
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[添加mesh导出程序](https://github.com/FreeCAD/FreeCAD/commit/e100971fa0a0c17b5e4906ac540fa31ac0d11766)
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[添加求解器，写入程序，任务程序，约束程序](https://github.com/FreeCAD/FreeCAD/commit/cdcd271b4c97a27431dc28d852f6ed7e171dba67)
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[添加求解器单元测试](https://github.com/FreeCAD/FreeCAD/commit/005c66f4ecc7fb1690a54592a00ec490146b985d)
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[添加文档](https://github.com/FreeCAD/FreeCAD/commit/cfc08b811ff09628b1468e21e9e823587efc799a)
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[添加界面参数](https://github.com/FreeCAD/FreeCAD/commit/dfc01ec949525162c70648ea6d6d93c818907f1f)
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