12.10. Compute Feature Reference C-Axis Misalignments
Group (Subgroup)
Statistics (Crystallography)
Description
This Filter measures how much the C-axis orientation varies within each Feature (grain) in hexagonal materials. It does this by comparing the C-axis direction of each individual Cell (voxel) to the average C-axis direction for the grain it belongs to.
This metric is useful for characterizing intragranular orientation gradients – regions within a grain where the crystal lattice has rotated relative to the grain’s average orientation, which can indicate deformation, subgrain boundaries, or measurement noise.
What This Filter Computes
For each Cell, the filter calculates the angle (in degrees) between that cell’s C-axis and the average C-axis of its parent Feature. The filter then computes summary statistics per Feature:
Average misalignment – the mean C-axis deviation across all cells in the grain
Standard deviation – how much the deviation varies within the grain
A low average misalignment indicates a grain with a uniform C-axis orientation. A high value suggests significant internal orientation variation.
Hexagonal Materials Only
This filter requires at least one hexagonal crystal structure phase (6/m or 6/mmm). Non-hexagonal phases are skipped. See the Compute Average C-Axis Orientations documentation for an explanation of why C-axis calculations are restricted to hexagonal materials.
Note
Results may differ from the DREAM3D 6.6 version by approximately 0.0001 degrees due to improved double-precision calculations for cross-platform accuracy.
Required Input Sources
Cell Feature Ids – produced by a segmentation filter such as Segment Features (Misorientation) or Segment Features (C-Axis Misalignment).
Cell Quaternions – typically read from EBSD data via Read H5EBSD, Read CTF Data, or Read ANG Data.
Cell Phases – typically read from EBSD data alongside the quaternions.
Average C-Axes – produced by Compute Average C-Axis Orientations.
Crystal Structures – ensemble-level array read from EBSD data or created by Create Ensemble Info.
Input Image Geometry
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Image Geometry |
Geometry Selection |
Image |
The path to the input image geometry |
Input Cell Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Cell Feature Ids |
Array Selection |
Allowed Types: int32 Comp. Shape: 1 |
Data Array that specifies to which Feature each Element belongs |
Cell Phases |
Array Selection |
Allowed Types: int32 Comp. Shape: 1 |
Specifies to which Ensemble each Cell belongs |
Cell Quaternions |
Array Selection |
Allowed Types: float32 Comp. Shape: 4 |
Specifies the orientation of the Cell in quaternion representation |
Input Feature Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Average C-Axes |
Array Selection |
Allowed Types: float32 Comp. Shape: 3 |
The direction of the Feature’s C-axis in the sample reference frame |
Input Ensemble Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Crystal Structures |
Array Selection |
Allowed Types: uint32 Comp. Shape: 1 |
Enumeration representing the crystal structure for each Ensemble |
Output Cell Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Feature Reference C-Axis Misorientations |
DataObjectName |
Misorientation angle (in degrees) between Cell’s C-axis and the C-axis of the Feature that owns that Cell |
Output Feature Data
Parameter Name |
Parameter Type |
Parameter Notes |
Description |
|---|---|---|---|
Average C-Axis Misorientations |
DataObjectName |
Average of the Feature Reference CAxis Misorientation values for all of the Cells that belong to the Feature |
|
Feature Stdev C-Axis Misorientations |
DataObjectName |
Standard deviation of the Feature Reference CAxis Misorientation values for all of the Cells that belong to the Feature |
Example Pipelines
EBSD_Hexagonal_Data_Analysis
License & Copyright
Please see the description file distributed with this Plugin
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.