Mesh Workbench/sv: Difference between revisions

Revision as of 13:28, 7 December 2013

Nät arbetsbänken hanterar triangelnät. Nät är en speciell typ av 3D objekt, sammansatt av trianglar som är ihopkopplade via deras kanter och hörn.

Ett exempel på ett nätobjekt

Många 3D applikationer använder nät som deras primära 3D objektstyp, som sketchup, blender, maya eller 3d studio max. Eftersom nät är mycket simpla objekt, som endast innehåller hörn (punkter), kanter och (triangulära) ytor, så är de mycket lätta att skapa, förändra, dela upp, sträcka ut, och kan lätt flyttas från en applikation till en annan utan några förluster. Eftersom de dessutom innehåller mycket simpel data, så kan 3D applikationer vanligtvis hantera mycket stora kvantiteter av dem utan några problem. Av dessa anledningar, så är nät ofta den valda 3D objekttypen i applikationer för filmer, animeringar, och bildbehandling.

In the field of engineering, however, meshes present one big limitation: They are very dumb objects, only composed of points,lines and faces. They are only made of surfaces, and have no mass information, so they don't behave as solids. In a mesh there is no automatic way to know if a point is inside or outside the object. This means that all solid-based operations, such as addition or subtraction, are always a bit difficult to perform on meshes, and return errors often.

In FreeCAD, since it is an engineering application, we would obviously prefer to work with more intelligent types of 3D objects, that can carry more informations, such as mass, solid behaviour, or even custom parameters. The mesh module was first created to serve as a testbed, but to be able to read, manipulate and convert meshes is also highly important for FreeCAD. Very often, in your workflow, you will receive 3D data in mesh format. You will need to handle that data, analyse it to detect errors or other problems that prevent converting them to more intelligent objects, and finally, convert them to more intelligent objects, handled by the Part Module.

Using the mesh module

The mesh module has currently a very simple interface, all its functions are grouped in the Mesh menu entry. The most important operations you can currently do with meshes are:

Import meshes in several file formats
Export meshes in several file formats
Convert Part objects into meshes
Analyse curvature, faces, and check if a mesh can be safely converted into a solid
Flip mesh normals
Close holes in meshes
Remove faces of meshes
Union, subtract and intersect meshes
Create mesh primitives, like cubes, spheres, cones or cylinders
Cut meshes along a line

These are only some of the basic operations currently present in the Mesh module interface. But the FreeCAD meshes can also be handled in many more ways by scripting.

PartDesign Workbench

Part Module

Index

Other languages:

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 Ett exempel på ett nätobjekt
-Many 3D applications use meshes as their primary type of 3D object, like [http://en.wikipedia.org/wiki/Sketchup sketchup], [http://en.wikipedia.org/wiki/Blender_(software) blender], [http://en.wikipedia.org/wiki/Maya_(software) maya] or [http://en.wikipedia.org/wiki/3d_max 3d studio max]. Since meshes are very simple objects, containing only vertices (points), edges and (triangular) faces, they are very easy to create, modify, subdivide, stretch, and can easily be passed from one application to another without any loss. Besides, since they contain very simple data, 3D applications can usually manage very large quantities of them without any problem. For those reasons, meshes are often the 3D object type of choice for applications dealing with movies, animation, and image creation.
+Många 3D applikationer använder nät som deras primära 3D objektstyp, som [http://sv.wikipedia.org/wiki/Sketchup sketchup], [http://sv.wikipedia.org/wiki/Blender blender], [http://sv.wikipedia.org/wiki/Maya_(datorprogram) maya] eller [http://sv.wikipedia.org/wiki/3ds_Max 3d studio max]. Eftersom nät är mycket simpla objekt, som endast innehåller hörn (punkter), kanter och (triangulära) ytor, så är de mycket lätta att skapa, förändra, dela upp, sträcka ut, och kan lätt flyttas från en applikation till en annan utan några förluster. Eftersom de dessutom innehåller mycket simpel data, så kan 3D applikationer vanligtvis hantera mycket stora kvantiteter av dem utan några problem. Av dessa anledningar, så är nät ofta den valda 3D objekttypen i applikationer för filmer, animeringar, och bildbehandling.
 In the field of engineering, however, meshes present one big limitation: They are very dumb objects, only composed of points,lines and faces. They are only made of surfaces, and have no mass information, so they don't behave as solids. In a mesh there is no automatic way to know if a point is inside or outside the object. This means that all solid-based operations, such as addition or subtraction, are always a bit difficult to perform on meshes, and return errors often.