10.120. Read Vtk Structured Points File

Group (Subgroup)

IO (Input)

Description

This filter reads a STRUCTURED_POINTS 3D array from a legacy .vtk file and stores it in an Image Geometry (a regular grid of equally-sized voxels). A STRUCTURED_POINTS file is a general form of an Image Geometry in which data values can be attached either to each voxel or to the corner points of each voxel. The file can be either binary or ASCII. The currently supported VTK attribute types are SCALARS and VECTORS; other attribute types are not read correctly and may cause the filter to fail.

Point Data vs. Cell Data

A STRUCTURED_POINTS file can store its values in two ways, and a single file may contain one or both:

  • CELL_DATA: one value per voxel, conceptually located at the voxel’s center. This is the most common case and maps directly onto an Image Geometry Cell Attribute Matrix.

  • POINT_DATA: values located at the eight corner (vertex) points of each voxel, so there are more point values than there are voxels.

The filter can read either or both, controlled by the Read Point Data and Read Cell Data options. To keep the data easy to visualize and compatible with the many DREAM3D-NX analysis tools that require an Image Geometry, the filter imports both kinds of data into their own separate Image Geometry, since both a cell-center grid and a corner-point grid form a structured rectilinear grid.

When both are read, two independent outputs are created: the Cell Data is placed under the Image Geometry named by the Data Container [Cell Data] parameter (default VTK Cell Data), and the Point Data is placed under the Image Geometry named by the Data Container [Point Data] parameter (default VTK Point Data). Each gets its own Cell Attribute Matrix to hold the imported arrays.

Spacing, Origin, and Units

The grid dimensions, spacing, and origin are read directly from the .vtk file’s DIMENSIONS, SPACING, and ORIGIN records. The spacing and origin are plain numbers with no embedded unit, so their length unit is whatever the file’s author intended (dimensionless to the reader).

Example Input

# vtk DataFile Version 2.0
GrainIds Stored in Vtk File
ASCII
DATASET STRUCTURED_POINTS
DIMENSIONS 3 4 6
SPACING 1 1 1
ORIGIN 0 0 0
POINT_DATA 72
SCALARS GrainIds char 1
LOOKUP_TABLE default
0 0 0 0 0 0 0 0 0 0 0 0
0 5 10 15 20 25 25 20 15
10 5 0 0 10 20 30 40 50
50 40 30 20 10 0 0 10 20
30 40 50 50 40 30 20 10 0
0 5 10 15 20 25 25 20 15
10 5 0 0 0 0 0 0 0 0 0 0 0 0 0

Required Input Sources

None — this filter reads directly from a .vtk file on disk.

Input Parameter(s)

Parameter Name

Parameter Type

Parameter Notes

Description

Input VTK File

FileSystemPath

The path to the input file

Read Point Data

Bool

Determines whether or not the Point Data will be read.

Read Cell Data

Bool

Determines whether or not the Cell Data will be read.

Output Point Data

Parameter Name

Parameter Type

Parameter Notes

Description

Data Container [Point Data]

DataGroupCreation

The data container for the Point Data.

Attribute Matrix Name [Point Data]

DataObjectName

The attribute matrix for the Point Data.

Output Cell Data

Parameter Name

Parameter Type

Parameter Notes

Description

Data Container [Cell Data]

DataGroupCreation

The data container for the Cell Data.

Attribute Matrix Name [Cell Data]

DataObjectName

The attribute matrix for the Cell Data.

Example Pipelines

DREAM3D-NX Help

If you need help, need to file a bug report or want to request a new feature, please head over to the DREAM3DNX-Issues GitHub site where the community of DREAM3D-NX users can help answer your questions.