## VertexDeclaration class

The declaration of a custom defined vertex's structure



The VertexDeclaration type exposes the following members:

### Constructors
| Constructor | Description |
| :- | :- |
| [`__init__(self)`](/3d/python-net/aspose.threed.utilities/vertexdeclaration/__init__/#) | Constructs a new instance of VertexDeclaration |


### Properties
| Property | Description |
| :- | :- |
| [sealed](/3d/python-net/aspose.threed.utilities/vertexdeclaration/sealed) | A [`VertexDeclaration`](/3d/python-net/aspose.threed.utilities/vertexdeclaration) will be sealed when its been used by TriMesh`1 or [`TriMesh`](/3d/python-net/aspose.threed.entities/trimesh), no more modifications is allowed. |
| [count](/3d/python-net/aspose.threed.utilities/vertexdeclaration/count) | Gets the count of all fields defined in this [`VertexDeclaration`](/3d/python-net/aspose.threed.utilities/vertexdeclaration) |
| [size](/3d/python-net/aspose.threed.utilities/vertexdeclaration/size) | The size in byte of the vertex structure. |


### Indexer
| Name | Description |
| :- | :- |
| [index] |  |


### Methods
| Method | Description |
| :- | :- |
| [`clear(self)`](/3d/python-net/aspose.threed.utilities/vertexdeclaration/clear/#) | Clear all fields. |
| [`add_field(self, data_type, semantic, index, alias)`](/3d/python-net/aspose.threed.utilities/vertexdeclaration/add_field/#aspose.threed.utilities.vertexfielddatatype-aspose.threed.utilities.vertexfieldsemantic-int-str) | Add a new vertex field |
| [`from_geometry(, geometry, use_float)`](/3d/python-net/aspose.threed.utilities/vertexdeclaration/from_geometry/#aspose.threed.entities.geometry-bool) | Create a [`VertexDeclaration`](/3d/python-net/aspose.threed.utilities/vertexdeclaration) based on a [`Geometry`](/3d/python-net/aspose.threed.entities/geometry)'s layout. |
| [`compare_to(self, other)`](/3d/python-net/aspose.threed.utilities/vertexdeclaration/compare_to/#aspose.threed.utilities.vertexdeclaration) | Compares this instance to a specified object and returns an indication of their relative values. |



### See Also
* module [`aspose.threed.utilities`](..)
* class [`Geometry`](/3d/python-net/aspose.threed.entities/geometry)
* class [`TriMesh`](/3d/python-net/aspose.threed.entities/trimesh)
* class [`VertexDeclaration`](/3d/python-net/aspose.threed.utilities/vertexdeclaration)