The Auto-align algorithms are based on GD&T datum precedence principles and the native degrees of freedom (DOF) of each feature type.
DOF of Supported Features
The supported features are grouped into the following six DOF-based cases, detailed in this table:
| DOF Case | Feature Types | DOF Constraints |
Planar |
Planes, 3D Widths |
R1 R2 T3 |
Axial |
Cylinder, 3D lines, Cones* |
R1 R2 T1 T2 |
2D Line |
Lines (on a surface), 2D Widths |
R1 T2 |
1D Point |
Vector Points, Round Slots*, Square Slots* |
T1 |
2D Points |
Circles, Ellipses*, Edge Points, Angle Points |
T1 T2 |
3D Points |
Spheres, Corner Points |
T1, T2, T3 |
* These features are treated differently in the QuickAlign algorithm:
Cone features are treated as cylinders.
Ellipses are treated as circles.
Slot features (both round and square) are treated as one-dimensional vector points with their surface normal vector pointing in the direction of the slot width.
Table Key:
R1 - Rotation DOF about the first coordinate axis
R2 - Rotation DOF about the second coordinate axis
T1 - Translation DOF in first coordinate axis direction
T2 - Translation DOF in the second coordinate axis direction
T3 - Translation DOF in the third coordinate axis direction