Point Sample Triangle Geometry¶
Group (Subgroup)¶
DREAM3D Review (Geometry)
Description¶
This Filter randomly samples point locations on Triangles in a Triangle Geometry. The sampled point locations are then used to construct a Vertex Geometry. The number of point samples may either be specified manually or by inferring from another Geometry:
| Geometry | Source for Number of Samples |
|---|---|
| Image | Number of cells |
| Rectilinear Grid | Number of cells |
| Vertex | Number of vertices |
| Edge | Number of vertices |
| Triangle | Number of vertices |
| Quadrilateral | Number of vertices |
| Tetrahedral | Number of vertices |
In order to ensure an even sampling of the total surface are of the Triangle Geometry, the average number of points sampled per triangle is made proportional to the area of the triangle. Within a given Triangle, a point is chosen using the following approach:
where 
are the coordinates of the sampled point; 
, 
, and 
are the coordinates of the vertices beloning to the Triangle; and 
and 
are random real numbers on the interval 
. This approach has the benefit of uniform sampling within the Triangle area, and functions correctly regardless of the dimensionality of the space embedding (i.e., whether the Triangle is in the plane or embedded in 3D).
The user may opt to use a mask to prevent certain Triangles from being sampled; where the mask is false, the Triangle will not be sampled. Additionally, the user may choose any number of Face Attribute Arrays to transfer to the created Vertex Geometry. The vertices in the new Vertex Geometry will gain the values of the Faces from which they were sampled.
Parameters¶
| Name | Type | Description |
|---|---|---|
| Source for Number of Samples | Enumeration | Whether to input the number of samples manually or use another Geometry to determine the number of samples |
| Number of Sample Points | int32_t | Number of sample points to use, if Manual is selected for Source for Number of Samples |
| Use Mask | bool | Whether to use a boolean mask array to ignore certain Trianlges flagged as false from the sampling algorithm |
Required Geometry¶
Triangle
Required Objects¶
| Kind | Default Name | Type | Component Dimensions | Description |
|---|---|---|---|---|
| Data Container | TriangleDataContainer | N/A | N/A | Data Container holding the Triangle Geometry to sample |
| Data Container | None | N/A | N/A | Data Container holding the Geometry used to determine the number of samples, if Other Geometry is selected for Source for Number of Samples |
| Face Attribute Array | FaceAreas | double | (1) | Specifies the area of each Face |
| Face Attribute Array | Mask | bool | (1) | Specifies if the Face can be sampled, if Use Mask is checked |
Created Objects¶
| Kind | Default Name | Type | Component Dimensions | Description |
|---|---|---|---|---|
| Data Container | VertexDataContainer | N/A | N/A | Data Container holding the Vertex Geometry that represents the sampling points |
| Vertex Attribute Matrix | VertexData | Vertex | N/A | Vertex Attribute Matrix for the created Vertex Data Container |
Example Pipelines¶
License & Copyright¶
Please see the description file distributed with this plugin.
DREAM3D Mailing Lists¶
If you need more help with a filter, please consider asking your question on the DREAM3D Users mailing list: