Alignment Editor

Intro

The Alignment Editor plugin modifies the alignment of the bridge models by transforming node geometry from an initial reference alignment to a new target alignment and automatically updating beta angles of vertical elements. 

Developed with

Benefits of this plugin

• Alignment Aware Transformation: Automatically remaps the model, accurately transferring the relative distance, perpendicular offset, and elevation of every node to the new alignment.
• Time Saving: Removes the need for manual node repositioning, reducing hours of work to a single click.
• Error Reduction: Eliminates manual coordinate edits, significantly reducing geometric and data handling errors. 
• Flexible Interpolation: Provides multiple interpolation options to match alignment geometry intent.
• Automatic Orientation Update: Updates beta angles of vertical elements to maintain consistent local axes along the new alignment.
  
   

How to use this plugin?

1. Initial Points 

   The Initial Points table defines the initial alignment. This can be populated in two ways:

   • Import Coordinates Click Import Coordinates to automatically extract coordinates from the currently selected nodes in the MIDAS CIVIL NX model.

   • Manual Entry Alternatively, users can manually enter or edit the Initial Points table by specifying the required X, Y, and Z coordinates directly.

      

2. Final Points 

   Define the target alignment by manually entering the X, Y, and Z coordinates into the Final Points table. These points represent the desired final alignment geometry.

    

3. Interpolation Method 

   Select the interpolation method used to generate the alignment curve between points. Available options are Cubic, Akima, Makima, and PCHIP.

    

4. Update Alignment 

   Click Update Alignment to apply the transformation. Upon successful completion, the confirmation message “Alignment modified” is displayed.

[Alignment Editor]
 

Note

• Interpolation Selection:

The choice of interpolation method affects how the alignment curve passes through the control points.

1. Cubic provides a smooth curve but may overshoot or undershoot near sharp changes.
2. Akima and Makima reduce overshoot.
3. PCHIP (Piecewise Cubic Hermite Interpolating Polynomial) ensures the curve stays strictly within the bounds of adjacent points.

• Alignment Point Requirements:

Both the Initial points and Final points tables must contain at least two rows. The X-coordinates must be in ascending order.

• End point Behaviour:

Nodes located outside the X-range of the initial alignment are mapped using a rigid rotation about the nearest alignment endpoint.
 

Reference links:

1. scipy.interpolate.CubicSpline
2. scipy.interpolate.Akima1DInterpolator
3. scipy.interpolate.PchipInterpolator

Conclusion

The Alignment editor realigns bridge models to updated alignment while preserving geometric relationships. It automatically updates node coordinates and element orientations, delivering a complete alignment modification workflow in MIDAS Civil NX.