OpenBridge Modeler

Complex by PI

Used to create a linear element with curves based on user input of PI (point of intersection) locations.

You can access this tool from the following:

  • Ribbon: Geometry > Horizontal > Complex Geometry split button

Complex By PI creates a linear element with curves based on user input of PI (point of intersection) locations. The curves can include transitions or set the radius to zero for no curves at the PI.

The transitions on the curves can be arc transitions or clothoid spirals using the following methods. See Spiral from Element for a description of the various spiral parameters.

  • Spiral - Length

  • Spiral - A-Value

  • Spiral - Deflection

  • Spiral - Delta R

  • Spiral - RL

  • Curve - Length

  • Curve - Deflection

  • Curve - Delta R

  • Curve - Ratio


  1. Click Complex By PI. The Complex Element By PI dialog displays.

  2. Data point to set the beginning of the element.

  3. Data point to set the second PI.

  4. Data point to set the third PI. Radius always applies to the PI prior to the one where the data point is currently being set. You can edit the radius by keying in a new value in the prompt. This is a triple toggle input. Toggle with left-right arrow keys to set back and ahead transition parameters.

  5. Continue to data point to add more PI points. Click the Reset button to stop adding PI points.


Manipulators are available for:

  • Distance and direction on each line segment

  • Radius and transition parameter on each curve

  • Drag handles at PI points


An ordered list of the line and curve segments is shown in the top tree portion in Element Information. Selecting each line or curve will show the properties pertaining to that portion of the complex.