Use the create parabola by best fit command to use a series of AutoCAD Civil 3D points, AutoCAD points, existing entities, or clicks on screen as a basis to create an AutoCAD parabola.
The best-fitting parabola through the points is calculated. You can then use a dialog box to exclude any of the specified points or to select one or two pass-through points.
When using the best fit commands for profile design, use the Create Parabola command for vertical curves. See Vertical Curve Design for more information.
To create an AutoCAD parabola by best fit from existing entities
- If you are creating a best fit parabola for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
- Click Home tab
Draw panel Best Fit drop-down Create Best Fit Parabola
. - In the Parabola By Best Fit Dialog Box, select From Entities. Specify the tessellation and mid-ordinate tolerance settings.
- Select one or more of the entities listed at the command line.
As you select entities in the drawing window, a white X marks each regression point and a temporary, dashed parabola is displayed in real time.
- If you selected a profile object, specify the starting and ending station on the Specify Station Range Dialog Box.
- Press Enter to complete the command.
- In the Panorama window, use the Regression Data vista to make changes to the regression points.
As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.
- Create the AutoCAD parabola:
- Clik
to create the parabola and keep the regression data. You may then use the data as a basis to create more parabolas. - Click
to create the parabola, clear the regression data, and close the Regression Data vista.
- Clik
- If desired, convert the AutoCAD parabola to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.
To create an AutoCAD parabola by best fit by clicking on screen
- If you are creating a best fit parabola for a profile, set the profile view style vertical exaggeration to 1. See Creating and Editing Profile View Styles for more information.
- Click Home tab Draw panel Best Fit drop-down Create Best Fit Parabola.
- In the Parabola By Best Fit Dialog Box, select By Clicking On The Screen.
- Select a starting point and at least two other points.
As you select points in the drawing window, a white X marks each regression point and a temporary, dashed parabola is displayed in real time.
- Press Enter to complete the command.
- In the Panorama window, use the Regression Data vista to make changes to the regression points.
As you highlight a row in the Regression Data vista, the corresponding regression point in the drawing window will be highlighted in red.
- Create the AutoCAD parabola:
- Clik to create the parabola and keep the regression data. You may then use the data as a basis to create more parabolas.
- Click to create the parabola, clear the regression data, and close the Regression Data vista.
- Clik
- If desired, convert the AutoCAD parabola to an alignment or profile entity. See Converting AutoCAD Entities to Alignment Subentities or Converting AutoCAD Entities to Profile Subentities for more information.