.. role:: blue
   :class: blue

Mesh and Segmentation Attributes
================================
.. _Mesh_and_Segmentation_Attributes_:

.. kernel version: 118027

As mentioned above, mesh and segmentation attributes are used to associate various types of values with topological elements of a polygon object – vertices, edges and facets of a mesh, regions, edges and vertices of segmentation.

Some attribute types are unique – in all algorithms a polygon object has only one attribute of this type, or the attribute does not exist. These attributes include:

- :blue:`MbHalfedgeAttrPoint3D` – 3D points for vertices;
- :blue:`MbHalfedgeAttrParameters` – 2D parameters for vertices;
- :blue:`MbHalfedgeAttrParamByEdge` – edge-dependent 2D parameters;
- :blue:`MbHalfedgeAttrNormalsVertex` – normals;
- :blue:`MbHalfedgeAttrCurvaturesVertex` – curvatures;
- :blue:`MbHalfedgeAttrDensityVertex` – target facet size for vertices;
- :blue:`MbHalfedgeAttrDihedralAngles` – dihedral angles for edges;
- :blue:`MbHalfedgeAttrStrains` – stresses in triangles;
- :blue:`MbHalfedgeAttrSurfaces` – surfaces for regions.

The remaining attributes are usually auxiliary and can be present in any number depending on the specific task. These include:

- :blue:`MbHalfedgeAttrBoolFacet`;
- :blue:`MbHalfedgeAttrBoolEdge`;
- :blue:`MbHalfedgeAttrBoolVertex`;
- :blue:`MbHalfedgeAttrUintFacet`;
- :blue:`MbHalfedgeAttrUintEdge`;
- :blue:`MbHalfedgeAttrUintVertex`;
- :blue:`MbHalfedgeAttrIntFacet`;
- :blue:`MbHalfedgeAttrIntEdge`;
- :blue:`MbHalfedgeAttrIntVertex`;
- :blue:`MbHalfedgeAttrSizetFacet`;
- :blue:`MbHalfedgeAttrSizetEdge`;
- :blue:`MbHalfedgeAttrSizetVertex`;
- :blue:`MbHalfedgeAttrDoubleFacet`;
- :blue:`MbHalfedgeAttrDoubleEdge`;
- :blue:`MbHalfedgeAttrDoubleVertex`;
- :blue:`MbHalfedgeAttrFloatFacet`;
- :blue:`MbHalfedgeAttrFloatEdge`;
- :blue:`MbHalfedgeAttrFloatVertex`;
- :blue:`MbHalfedgeAttrDirectionEdge3D`;
- :blue:`MbHalfedgeAttrNormalsFacet`;
- :blue:`MbHalfedgeAttrDirectionVertex3D`.

There is no possibility for a user to create their own attribute type.