Mesh
Introduction
Dans FreeCAD, le mot "Mesh" est normalement utilisé pour désigner un Mesh Object (Mesh::MeshObject
class), un type d'objet qui définit les données 3D mais n'est pas un solide "Shape".
Les maillages sont des objets très simples, ne contenant que des sommets (points), des arêtes et des faces triangulaires. En général, ils sont faciles à créer, à modifier, à subdiviser et à étirer, et peuvent être transmis d'une application à une autre sans aucune perte de détails. De plus, comme les maillages contiennent des données très simples, les applications 3D comme les logiciels d'animation et les jeux vidéo peuvent en gérer de très grandes quantités sans utiliser beaucoup de ressources informatiques.
Cependant, dans le domaine de l'ingénierie, les maillages présentent une grande limitation: ils ne sont constitués que de surfaces et n'ont pas d'informations de "masse", ils ne se comportent donc pas comme des "solides". Cela signifie que les opérations à base de solides, comme l'addition ou la soustraction booléenne, sont difficiles à effectuer sur les maillages. De plus, comme ils sont définis par des points individuels, ils sont difficiles à décrire de façon paramétrique.
See Mesh MeshObject for more information about this type of object, and see Polygon mesh for generic information in computer systems.
How to use
Meshes are normally created by internal functions of the Mesh Workbench, or by importing mesh format files, like STL and OBJ.
Essentially, every object derived from a Mesh Feature (Mesh::Feature
class) is expected to hold and manipulate a Mesh.
Since FreeCAD is designed to be a solid modeller primarily, it is better suited to deal with solid Shapes. It can import and display Meshes in the 3D view, but to transform them or create new geometry, the Mesh first needs to be converted to a Shape (see Part ShapeFromMesh). In many cases, this conversion is not automatic, and requires re-creating the geometry using solid modelling techniques, making use of Part and PartDesign tools.
Finite element meshes
In FreeCAD the word "Mesh" may also refer to a specific object that will be used in finite element analysis (FEA).
When an object with a solid Shape is used in the FEM Workbench it will be discretized into a triangular mesh. In this case, the resulting object is a Fem FemMeshObject (Fem::FemMeshObject
class), and is not derived from a Mesh Feature (Mesh::Feature
class).
For more information see FEM Workbench and FEM Mesh.
- Miscellaneous: Import mesh, Export mesh, Create mesh from shape, Regular solid, Unwrap Mesh, Unwrap Face
- Modifying: Harmonize normals, Flip normals, Fill holes, Close hole, Add triangle, Remove components, Remove components by hand, Smooth, Refinement, Decimation, Scale
- Boolean: Union, Intersection, Difference
- Cutting: Cut mesh, Trim mesh, Trim mesh with a plane, Create section from mesh and plane, Cross-sections
- Components and segments: Merge, Split by components, Create mesh segments, Create mesh segments from best-fit surfaces
- Materials: Solid, Fluid, Nonlinear mechanical, Reinforced (concrete); Material editor
- Element geometry: Beam (1D), Beam rotation (1D), Shell (2D), Fluid flow (1D)
Constraints
- Electromagnetic: Electrostatic potential, Current density, Magnetization
- Geometrical: Plane rotation, Section print, Transform
- Mechanical: Fixed, Displacement, Contact, Tie, Spring, Force, Pressure, Centrif, Self weight
- Thermal: Initial temperature, Heat flux, Temperature, Body heat source
- Overwrite Constants: Constant vacuum permittivity
- Solve: CalculiX Standard, Elmer, Mystran, Z88; Equations: Deformation, Elasticity, Electrostatic, Electricforce, Magnetodynamic, Magnetodynamic 2D, Flow, Flux, Heat; Solver: Solver control, Solver run
- Results: Purge, Show; Postprocessing: Apply changes, Pipeline from result, Warp filter, Scalar clip filter, Function cut filter, Region clip filter, Contours filter, Line clip filter, Stress linearization plot, Data at point clip filter, Filter function plane, Filter function sphere, Filter function cylinder, Filter function box
- Additional: Preferences; FEM Install, FEM Mesh, FEM Solver, FEM CalculiX, FEM Concrete; FEM Element Types
- Core: App DocumentObject
- Basic: App FeaturePython, App GeoFeature, Part Feature, Mesh Feature, Fem FemMeshObject
- Internal shapes: Part TopoShape, Mesh MeshObject, Fem FemMesh
- Structure: App DocumentObjectGroup (Std Group), App Part (Std Part), App Link (Std LinkMake)
- Derived: Part Part2DObject, Sketcher SketchObject, PartDesign Body, PartDesign Feature
- Getting started
- Installation: Download, Windows, Linux, Mac, Additional components, Docker, AppImage, Ubuntu Snap
- Basics: About FreeCAD, Interface, Mouse navigation, Selection methods, Object name, Preferences, Workbenches, Document structure, Properties, Help FreeCAD, Donate
- Help: Tutorials, Video tutorials
- Workbenches: Std Base, Assembly, BIM, CAM, Draft, FEM, Inspection, Mesh, OpenSCAD, Part, PartDesign, Points, Reverse Engineering, Robot, Sketcher, Spreadsheet, Surface, TechDraw, Test Framework
- Hubs: User hub, Power users hub, Developer hub