Appearance
Appearance is a dual purpose attribute. It defines rendering attributes for 0-dim geometries (points, vertices and sets of them).
It is also the "base" for line style, which defines rendering attributes for 1-dim geometries (lines, curves, edges, wires and sets of them)
and material (surfaces, faces, etc.).
Appearance can be accessed via IAppearance_DG Interface returned by IEntity_DG.GetAppearance(). Use IAppearance_DG.GetDimension() to determine the actual type of the appearance:
Appearance of BRep Shapes
Appearance of the top shape of a BRep geometry is the appearcnce of the entity, which can be accesed as described above.
In addition to that, faces can have own appearance, which overrides apperance of the entity, when set. Use IBRepShape_DG.GetAppearance() to create or access appearance attribute of the face.
Use IBRepShape_DG.DeleteAppearance() to remove the per face appearance.
Appearance of mixed dimension compounds in BRep Geometries
IAppearance_DG.GetDimension() coincides with the dimension returned by IGeometry_DG.GetDimension() called for geometry of the entity. An exception is the case of a compound shape with mixed dimension sub-shapes in a "BRep" geometry type. In the later case IGeometry_DG.GetDimension() returns eUd (unknown) and appearances for each dimension are stored in properties of the entity.
To access per dimension appearances for a mixed dimension compound, obtain extended properties via IEntity_DG.GetExtendedProperties() and use IDictionary_DG.GetInterface(Property_name), where Property_name is:
And query the interface specified in the above table from the returned object. See also IBRepCompundTest.MixedDimsTest_Apearance() in Samples\NET\C#\Tests\InterfaceTests sample project installed with the product.
IEntity_DG.GetAppearance() returns one of the per dimension appearances in the case. Which one, depends on the history of the entity. Use IAppearance_DG.GetDimension() to determine the case.
See also: Material
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